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Physiology
02/04/2010

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Cards

Term
The chemical force for which of the following ions is directed into the cell?
A)

potassium only

B)

both potassium and sodium

C)

calcium only

D)

sodium only

E)

both sodium and calcium
Definition
E)

both sodium and calcium
Term
Which of the following is found in greater concentration inside the cell than outside?

2)

_______

A)

potassium

B)

chloride

C)

calcium

D)

water
Definition
A)

potassium
Term
When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move ________.



A)

from lower to higher energy

B)

from higher to lower energy

C)

out of a cell

D)

into a cell

E)

in both directions; there is no preference
Definition
B)

from higher to lower energy
Term
Any difference in energy across a membrane is considered the ________ that pushes a molecule in one direction or the other.


A)

antagonistic force

B)

magnetic force

C)

driving force

D)

channel

E)

carrier
Definition
C)

driving force
Term
Of the gradients listed below, which is the most accurate description of the force that ultimately determines the movement of ions across the membrane?


A)

chemical gradient

B)

electrochemical gradient

C)

potential gradient

D)

electrical gradient

E)

concentration gradient
Definition
B)

electrochemical gradient
Term
Molecules tend to move spontaneously ________ their chemical gradient.



A)

down

B)

around

C)

up

D)

over

E)

through


Definition
A)

down
Term
When more than one ion species (i.e., Na+ and K+) is present on both sides of the membrane, the chemical driving force acting on Na+ will include ________.



A)

the most concentrated ion only

B)

sodium only

C)

all ions present

D)

all positively charged ions

E)

all negatively charged ions
Definition
B)

sodium only
Term
________ is a reflection of the unequal distribution of positive and negative ions across the plasma membrane.



A)

Electrochemical driving force

B)

Chemical gradient

C)

Membrane potential

D)

Chemical driving force

E)

Extracellular potential
Definition
C)

Membrane potential
Term
Comparing intracellular to extracellular fluid, the intracellular fluid has a ________ charge relative to the outside of a cell due to the presence of more ________ in that solution.



A)

negative : anions

B)

positive : cations

C)

negative : cations

D)

positive : anions

E)

neutral : cations



Definition
A)

negative : anions
Term
The unequal distribution of charge in solutions on either side of a membrane will lead to a ________ of charge across the membrane and a ________ of counter ions in a region close to the membrane.


A)

collection : clustering

B)

collection : restriction

C)

buildup : restriction

D)

separation : restriction

E)

separation : clustering
Definition
E)

separation : clustering
Term
Based solely upon its electrical charge, the inside of a typical cell will tend to attract extracellular ________ to move inward.



A)

ions whose concentration gradient allows them

B)

proteins

C)

uncharged ions

D)

cations

E)

anions
Definition
D)

cations
Term
Which of the following factors does NOT directly affect the direction or magnitude of the electrical driving force?



A)

the amplitude of membrane potential

B)

an ion's charge

C)

the sign of the membrane potential

D)

the quantity of charge carried by an ion

E)

the molecular weight of an ion
Definition
E)

the molecular weight of an ion
Term
Which of the following is NOT a determinant of the magnitude and direction of the equilibrium potential for an ion?


A)

valence of the ion

B)

lipid solubility of the ion

C)

concentration difference

D)

direction of the concentration difference

E)

charge of the ion
Definition
B)

lipid solubility of the ion
Term
If a positively charged ion is more concentrated outside the cell, the forces required to balance the chemical gradient would be directed ________. Thus, the equilibrium potential for this ion would be ________ charged.


A)

inward : negatively

B)

outward : positively

C)

outward : negatively

D)

inward : positively

E)

outward : neutrally
Definition
B)

outward : positively
Term
Which of the following cells would have a greater electrical attraction for sodium ions to enter the cell?



A)

cell with membrane potential = +20 mV

B)

cell with membrane potential = -70 mV

C)

cell with membrane potential = 0 mV

D)

cell with membrane potential = -90 mV

E)

cell with membrane potential = -50 mV
Definition
D)

cell with membrane potential = -90 mV

Term
If a negatively charged ion is more concentrated outside the cell, the forces required to balance the chemical gradient would be directed ________. Thus, the equilibrium potential for this ion would be ________ charged.



A)

outward : neutrally

B)

outward : negatively

C)

inward : positively

D)

outward : positively

E)

inward : negatively
Definition
B)

outward : negatively
Term
If a negatively charged ion is more concentrated inside the cell, the forces required to balance the chemical gradient would be directed ________. Thus, the equilibrium potential for this ion would be ________ charged.



A)

inward : positively

B)

outward : negatively

C)

inward : negatively

D)

outward : neutrally

E)

outward : positively
Definition
A)

inward : positively
Term
If a positively charged ion is more concentrated inside the cell, the forces required to balance the chemical gradient would be directed ________. Thus, the equilibrium potential for this ion would be ________ charged.



A)

outward : neutrally

B)

inward : negatively

C)

outward : positively

D)

inward : positively

E)

outward : negatively
Definition
B)

inward : negatively
Term
The ________ can be used to determine an ion's equilibrium potential.



A)

Nernst equation

B)

Navier Stokes equation

C)

oscilloscope

D)

intracellular voltmeter

E)

concentration of an ion only
Definition
A)

Nernst equation
Term
The potassium equilibrium potential is -94 mV. This means that ________.



A)

at -94 mV, potassium movement is opposed exactly by sodium movement

B)

at -94 mV, the chemical force for potassium movement is zero

C)

at the resting membrane potential of neurons, potassium is at equilibrium

D)

at -94 mV, the chemical force for potassium movement is opposed exactly by the electrical force

E)

at -94 mV, the electrical force for potassium movement is zero
Definition
D)

at -94 mV, the chemical force for potassium movement is opposed exactly by the electrical force
Term
An anion has an equilibrium potential of -40 mV. What direction are the chemical and electrical forces acting on the anion at the resting membrane potential (-70 mV)?



A)

Both the chemical and electrical forces are directed out of the cell.

B)

There is insufficient information to answer this question.

C)

The chemical force is directed out of the cell and the electrical force is directed into the cell.

D)

Both the chemical and electrical forces are directed into the cell.

E)

The chemical force is directed into the cell and the electrical force is directed out of the c
Definition
E)

The chemical force is directed into the cell and the electrical force is directed out of the cell.


Term
Which of the following best describes the potassium equilibrium potential?



A)

+94 mV

B)

+60 mV

C)

-94 mV

D)

-60 mV
Definition
C)

-94 mV
Term
An anion is found in greater concentration inside the cell than outside. Which of the following statements best describes forces acting on the anion at the resting membrane potential (-70 mV)?



A)

The chemical force is directed out of the cell and the electrical force is directed into the cell.

B)

The chemical force is directed into the cell and the electrical force is directed out of the cell.

C)

There is insufficient information to answer this question.

D)

Both the chemical and electrical forces are directed into the cell.

E)

Both the chemical and electrical forces are directed out of the cell.
Definition
C)

There is insufficient information to answer this question
Term
The equilibrium potential for a cation is -20 mV. Which of the following statements is true when a cell is at the resting membrane potential (-70 mV)?



A)

The chemical force is directed into the cell and the electrical force is directed out of the cell.

B)

There is insufficient information to answer this question.

C)

The chemical force is directed out of the cell and the electrical force is directed into the cell.

D)

Both the chemical and electrical forces are directed into the cell.

E)

Both the chemical and electrical forces are directed out of the cell.
Definition
C)

The chemical force is directed out of the cell and the electrical force is directed
Term
Equilibrium potential describes the membrane potential where the ________ gradient balances the ________ gradient.

Definition
C)

chemical : electrical
Term
Which of the following is NOT required to determine equilibrium potential?
Definition
E)

size of the ion
Term
Which of the following does NOT directly determine the rate at which an ion will move passively across a membrane?
Definition
A)

amount of ATP available
Term
28)

Which of the following would NOT increase the rate of diffusion across the phospholipid bilayer of the plasma membrane?

28)

______

A)

greater lipid solubility

B)

greater number of protein carriers

C)

greater concentration gradient

D)

greater available surface area

E)

smaller size
Definition
B)

greater number of protein carriers
Term
Which of the following pairs of characteristics is more likely to make a substance diffuse through the cell membrane?

29)

______

A)

small, polar molecule

B)

small, non-polar molecule

C)

large, non-polar molecule

D)

large amphipathic molecule

E)

large, polar molecule
Definition
B)

small, non-polar molecule
Term
Oxygen diffuses from blood into cells down its concentration gradient. As cells become more active and oxidative phosphorylation increases in the cell, which of the following occurs?

30)

______

A)

The concentration gradient for oxygen increases and oxygen movement into the cell increases.

B)

The concentration gradient for oxygen decreases and oxygen movement into the cell decreases.

C)

The concentration gradient for oxygen decreases and oxygen movement into the cell increases.

D)

The concentration gradient for oxygen and its rate of movement into the cell do not change.

E)

The concentration gradient for oxygen increases and oxygen movement into the cell decreases.
Definition
A)

The concentration gradient for oxygen increases and oxygen movement into the cell increases.
Term
How will increases in the concentration difference of an unchanged molecule across a membrane affect the rate of diffusion between two compartments?

31)

______

A)

Diffusion rate will decrease.

B)

Diffusion rate will progressively decrease until zero.

C)

Diffusion rate will increase.

D)

Diffusion rate will not be affected.

E)

Diffusion rate will remain constant.
Definition
C)

Diffusion rate will increase
Term
The concentration of sodium is greater in the extracellular fluid compared to the intracellular fluid. If the membrane potential was equal to the equilibrium potential for sodium, then what would be the direction of the electrochemical force acting on sodium?

32)

______

A)

outward

B)

varies based on concentration of potassium in the intracellular and extracellular fluids

C)

varies by cell

D)

inward

E)

no force
Definition
E)

no force
Term
One way that membrane surface area is increased in absorptive cells is through increasing the ________ of the apical membrane.
Definition
D)

folding
Term
When a substance crossing the membrane is driven by diffusion, the net flux of that molecule can be described mathematically by ________.

34)

______

A)

the Goldman Hodgkins Katz equation

B)

Fick's Law

C)

Einstein's equation

D)

the Nernst equation

E)

the Navier Stokes equation
Definition
B)

Fick's Law
Term
Sodium permeability refers to a property of ________.

35)

______

A)

organelles

B)

lipid soluble molecules only

C)

molecules

D)

the cell membrane

E)

sodium
Definition
D)

the cell membrane
Term
Which of the following will NOT increase the net flux of an ion across a membrane?

36)

______

A)

increased concentration gradient across the membrane

B)

enhanced surface area

C)

elevated permeability of the membrane

D)

reduced surface area

E)

more channels for that ion in the membrane
Definition
D)

reduced surface area
Term
Molecules with a relatively high lipid solubility are capable of crossing the membrane ________.

37)

______

A)

only through specific protein channels

B)

through specific lipid channels

C)

only with the addition of energy

D)

directly across the lipid bilayer

E)

indirectly by moving across a carrier protein
Definition
D)

directly across the lipid bilayer
Term
Which of the following molecules is least likely to cross the plasma membrane?

38)

______

A)

fatty acid

B)

water

C)

steroids

D)

oxygen

E)

disaccharide
Definition
E)

disaccharide
Term
Which of the following is NOT true for all three transport mechanisms: facilitated diffusion, primary active transport, and secondary active transport?

39)

______

A)

The transport mechanism has a limit to the total number of molecules that can be transported per unit of time.

B)

The transport mechanism requires energy.

C)

The transport mechanism requires a protein.

D)

Transport can be increased by increasing the number of transport molecules in the plasma membrane.

E)

The transport mechanism is specific for a particular solute(s).
Definition
B)

The transport mechanism requires energy.
Term
Which of the following transport mechanisms is passive?

40)

______

A)

movement of calcium out of the cytosol

B)

transport of sodium and potassium across the membrane by the Na+/K+ pump

C)

cotransport of glucose with sodium

D)

movement of sodium through ion channels

E)

countertransport of hydrogen ions with sodium
Definition
D)

movement of sodium through ion channels
Term
A carrier is a transmembrane protein that moves molecules across the membrane through ________.

41)

______

A)

a lipid-filled pore

B)

small gaps in the fluid portion of the membrane

C)

a water-filled pore

D)

conformational changes in the carrier proteins

E)

opening its gate and allowing molecules through
Definition
D)

conformational changes in the carrier proteins
Term
In general, the molecules that move through specific carrier proteins are determined by ________.

42)

______

A)

the molecule's lipid solubility

B)

a water-filled pore

C)

the size of a molecule

D)

conformational changes in the pore

E)

the unique binding sites on the channel or carrier protein
Definition
E)

the unique binding sites on the channel or carrier protein


Term
In facilitated diffusion, ________.

43)

______

A)

a molecule is moved against its concentration gradient with the assistance of a protein carrier molecule, but no energy is required

B)

a molecule is moved with its concentration gradient with the assistance of a protein carrier molecule, and no energy is required

C)

a molecule is moved with its concentration gradient while Na is moved against its concentration gradient

D)

a molecule is moved against its concentration gradient with the assistance of a protein carrier molecule and requires energy

E)

a molecule is moved against its concentration gradient while Na is moved with its concentration gradient
Definition
B)

a molecule is moved with its concentration gradient with the assistance of a protein carrier molecule, and no energy is required
Term
Which of the following transport mechanisms requires energy?

44)

______

A)

secondary active transport only

B)

facilitated diffusion only

C)

both primary active transport and facilitated diffusion

D)

primary active transport only

E)

both primary and secondary active transport
Definition
E)

both primary and secondary active transport


Term
In active transport, the affinity of the carrier protein for the molecule being transported is greater on which side of the membrane?

45)

______

A)

always the side facing the extracellular fluid

B)

on the side where the molecule is in lower concentration

C)

on the side where the molecule is in greater concentration

D)

always the side facing the intracellular fluid

E)

Neither; it is equal on both sides of the membrane.
Definition
B)

on the side where the molecule is in lower concentration
Term
What is the main difference between primary and secondary active transport?

46)

______

A)

One uses energy whereas the other requires no energy.

B)

The molecules that are transported access the binding sites differently.

C)

the form of energy (ATP vs. electrochemical gradient) used to move molecules across the membrane

D)

the direction that molecules are being moved across the membrane

E)

the location of the binding sites
Definition
C)

the form of energy (ATP vs. electrochemical gradient) used to move molecules across the membrane
Term
What are aquaporins?

47)

______

A)

water channels

B)

ion channels

C)

oxygen transporters

D)

ion transporters

E)

water-soluble molecules
Definition
A)

water channels
Term
Movement of water through aquaporins is ________.

48)

______

A)

based on electrical forces

B)

active

C)

coupled to ion movement

D)

a form of mediated transport

E)

passive
Definition
E)

passive
Term
Most water molecules that cross the plasma membrane do so by ________.

49)

______

A)

active transport by aquaporins

B)

diffusion through aquaporins

C)

active transport by ion channels

D)

diffusion through ion channels

E)

diffusion through the plasma membrane
Definition
B)

diffusion through aquaporins
Term
________ couples the movement of an ion against its electrochemical gradient to another ion that is moving down its electrochemical gradient that was established using cellular energy (ATP).

50)

______

A)

Primary active transport

B)

Primary passive transport

C)

Secondary active transport

D)

Secondary passive transport

E)

Tertiary passive transport
Definition
C)

Secondary active transport
Term
Primary active transporters are unique in their ability to couple the movement of ions directly to ________.

51)

______

A)

a channel

B)

another ion's electrochemical gradient

C)

ATP

D)

a carrier protein

E)

its electrochemical gradient
Definition
C)

ATP
Term
Pumps are different from carrier proteins in that they use energy to move ions ________.

52)

______

A)

in a preferred direction across the membrane

B)

in any direction they choose across the membrane

C)

in the direction determined by that ion's electrochemical gradient

D)

in the direction determined by that ion's chemical gradient only

E)

down their electrochemical gradient
Definition
A)

in a preferred direction across the membrane
Term
Which of the following is NOT a similarity between carrier proteins and pumps?

53)

______

A)

their specificity for certain ions

B)

their multiple binding sites

C)

Each has a maximal flux rate.

D)

their saturation kinetics

E)

their direct use of ATP
Definition
E)

their direct use of ATP
Term
In addition to functioning as a transporter, primary active transporters also function as ________ in order to make use of energy.

54)

______

A)

structural proteins

B)

carriers

C)

receptors

D)

channels

E)

enzymes
Definition
E)

enzymes
Term
The first step of the Na+/K+ pump's activity involves the binding of ________.

55)

______

A)

3 Na+ to their binding site on the inside of the cell

B)

2 K+ to their binding site on the inside of the cell

C)

2 K+ to their binding site on the outside of the cell

D)

3 Na+ to their binding site on the outside of the cell

E)

3 Na+ and 2 K+ to their respective binding sites
Definition
D)

3 Na+ to their binding site on the outside of the cell
Term
The hydrolysis of ATP on the Na+/K+ pump results in ________.

56)

______

A)

Na+ adhering to its binding site

B)

a conformational change that moves the Na+ binding site to the outside of the cell

C)

a conformational change that moves the K+ binding site to the outside of the cell

D)

a conformational change that moves the Na+ binding site to the inside of the cell

E)

a conformational change that moves the K+ binding site to the inside of the cell


Definition
D)

a conformational change that moves the Na+ binding site to the inside of the cell
Term
Na+ is released from its binding site on the Na+/K+ pump as a result of ________.

57)

______

A)

the binding of K+ to its binding site

B)

the interaction of the Na+ and K+ binding sites

C)

the exposure of the Na+ binding site to the inside of the cell

D)

the conformational change decreasing the affinity of the Na+ binding site

E)

the enzyme on the inside of the cell which cleaves the Na+ from its binding site


Definition
D)

the conformational change decreasing the affinity of the Na+ binding site
Term
Which of the following statements about the Ca2+ pump is FALSE?

58)

______

A)

Calcium is actively transported from an organelle into the cytosol.

B)

Calcium is actively transported from the cytosol into the extracellular fluid.

C)

It maintains low cytosolic calcium levels.

D)

The pump is also an ATPase.

E)

It is a form of primary active transport.
Definition
A)

Calcium is actively transported from an organelle into the cytosol
Term
In secondary active transport with sodium, which of the following is FALSE?

59)

______

A)

Sodium binds to a carrier molecule, changing its binding properties for another molecule to be transported across the cell membrane.

B)

Sodium always moves into the cell.

C)

The molecule being transported into the cell may move in or out, depending on the carrier molecule.

D)

The molecule being transported moves down its electrochemical gradient.

E)

ATP is necessary to produce an electrochemical gradient for sodium ions across the cell membrane.
Definition
D)

The molecule being transported moves down its electrochemical gradient
Term
Which of the following correctly describes cotransport of Y with sodium?

60)

______

A)

Y moves out of the cell as sodium moves into the cell.

B)

Not enough information is provided to answer this question.

C)

Y and sodium both move out of the cell.

D)

Y moves into the cell as sodium moves out of the cell.

E)

Y and sodium both move into the cell.
Definition
E)

Y and sodium both move into the cell.


Term
Which of the following statements about glucose cotransport with sodium is true?

61)

______

A)

Sodium moves out of the cell, but the movement of glucose will vary based on the type of cell.

B)

Glucose moves out of the cell while sodium moves into the cell.

C)

Glucose and sodium both move out of the cell.

D)

Glucose and sodium both move into the cell.

E)

Glucose moves into the cell while sodium moves out of the cell.
Definition
D)

Glucose and sodium both move into the cell.
Term
Which of the following statements about primary active transport is FALSE?

62)

______

A)

The Ca2+ pump always moves calcium into the extracellular fluid.

B)

Energy is used to change the affinity of the transporter for the solute being transported.

C)

The Na+/K+-pump transports two potassium ions into the cell and three sodium ions out of the cell.

D)

ATP directly provides the energy for transport.

E)

Phosphorylation of the carrier protein covalently regulates the carrier
Definition
A)

The Ca2+ pump always moves calcium into the extracellular fluid
Term
The concentration of an anion inside a cell is 0.3%. The concentration of this anion outside the cell is 0.1%. How could the cell obtain more of this ion inside the cell?

63)

______

A)

phagocytosis

B)

passive transport

C)

active transport

D)

osmosis

E)

exocytosis
Definition
C)

active transport
Term
Which of the following statements about the Na+/K+ pump is FALSE?

64)

______

A)

Two potassium ions are moved into the cell per ATP.

B)

It is a form of primary active transport.

C)

Three sodium ions are moved out of the cell per ATP.

D)

The pump is also an enzyme.

E)

The pumps activity is regulated through allosteric modulation.


Definition
E)

The pumps activity is regulated through allosteric modulation.


Term
Sodium-linked glucose transport, where both Na+ and glucose are moving in the same direction, is an example of ________.

65)

______

A)

exchange

B)

countertransport

C)

primary active transport

D)

symport

E)

antiport
Definition
D)

symport
Term
The sodium-proton exchanger is an example of a(n) ________.

66)

______

A)

cotransporter

B)

symporter

C)

antiporter

D)

primary active transporter

E)

passive transporter
Definition
C)

antiporter
Term
The flow of water across a membrane down its concentration gradient is called ________.

67)

______

A)

antiporting

B)

symporting

C)

leaking

D)

osmosis

E)

facilitated diffusion
Definition
D)

osmosis
Term
A membrane permeable to water separates a chamber into two compartments: A and B. Compartment A contains a 10 mM solution of non-permeating solute, whereas compartment B contains a 40 mM solution of non-permeating solute. Which of the following statements is true?

68)

______

A)

Water will move from side B to A, but solute will not move.

B)

Solute will move from side B to A, and water will move from side A to B.

C)

Solute will move from side A to B, and water will move from side B to A.

D)

Both water and solute will move from side B to A.

E)

Water will move from side A to B, but solute will not move.


Definition
E)

Water will move from side A to B, but solute will not move
Term
A cell is placed in a 200 mM NaCl solution. This solution is ________ and the cell will ________.

69)

______

A)

hypertonic : shrink

B)

hypotonic : shrink

C)

isotonic : not change size

D)

hypotonic : swell

E)

hypertonic : swell
Definition
A)

hypertonic : shrink
Term
If a solution contains 0.1 M glucose along with 0.15 M NaCl, what is the osmolarity of this solution?

70)

______

A)

350 mOsm

B)

400 mOsm

C)

0.25 M

D)

0.4 M

E)

250 mOsm
Definition
B)

400 mOsm
Term
If solution 1 (0.1 M glucose and 0.15 M NaCl) and solution 2 (0.4 M glucose) are separated by a membrane, then solution 1 is ________ relative to solution 2.

71)

______

A)

iso-osmotic

B)

hyperosmotic

C)

hypertonic

D)

hypotonic

E)

hypo-osmotic
Definition
A)

iso-osmotic
Term
If there is a difference in osmolarity between a cell and its environment, water will move ________ its osmotic pressure gradient.

72)

______

A)

up

B)

between

C)

across

D)

down

E)

through


Definition
A)

up
Term
The osmotic pressure of a solution is a(n) ________.

73)

______

A)

direct measure of its solute concentration

B)

direct measure of its solvent concentration

C)

indication of its glucose concentration

D)

indirect measure of its solvent concentration

E)

indirect measure of its solute concentration
Definition
E)

indirect measure of its solute concentration


Term
A cell is placed into a solution that has the same osmolarity. However, one of the ions inside the cell is able to move across the membrane (the solution the cell was placed into does not contain this ion). After a period of time, the solution into which the cell was placed would become ________.

74)

______

A)

hypertonic

B)

iso-osmolar

C)

hypotonic

D)

hypo-osmotic

E)

isotonic
Definition
A)

hypertonic
Term
A cell is placed into a solution that has the same osmolarity. However, one of the ions in the solution is able to move across the membrane (the cell does not contain this ion). After a period of time, the solution into which the cell was placed would become ________.

75)

______

A)

hypotonic

B)

hypertonic

C)

hyperosmotic

D)

isotonic

E)

iso-osmotic
Definition
A)

hypotonic
Term
White blood cells are an important component of our immune system. One thing they do is consume and destroy bacteria by extending their plasma membrane around the bacterium and bringing it inside the cell in a vesicle. By what process do they engulf the bacterium?

76)

______

A)

exocytosis

B)

phagocytosis

C)

pinocytosis

D)

transcytosis

E)

receptor-mediated endocytosis
Definition
B)

phagocytosis
Term
Vesicles formed during phagocytosis or endocytosis often fuse with the membrane of which of the following organelles?

77)

______

A)

rough endoplasmic reticulum

B)

mitochondria

C)

peroxisome

D)

lysosome

E)

smooth endoplasmic reticulum
Definition
E)

smooth endoplasmic reticulum


Term
Secretory vesicles are a part of what transport mechanism?

78)

______

A)

receptor-mediated endocytosis

B)

phagocytosis

C)

osmosis

D)

pinocytosis

E)

exocytosis
Definition
E)

exocytosis


Term
Which of the following correctly describes phagocytosis?

79)

______

A)

A cell synthesizes a product and packages it into vesicles. The product is released by phagocytosis.

B)

Cells non-specifically engulf extracellular fluid.

C)

Carrier proteins in the cell membrane transport a specific substance into the cell.

D)

Cells engulf large particles, such as bacteria, by phagocytosis.

E)

A substance in the extracellular fluid binds to specific receptors for it on the cell membrane inducing the formation of a coated pit. The coated pit invaginates and enters the cell by phagocytosis.
Definition
D)

Cells engulf large particles, such as bacteria, by phagocytosis
Term
Epithelial cells are polarized with different structures on either side of the cell. The portion of the cell that faces the lumen is called the ________ membrane.

80)

______

A)

basolateral

B)

ablumenal

C)

basement

D)

transport

E)

apical
Definition
E)

apical


Term
The extent of ion movement through the ________ space between epithelial cells is determined by the extent of ________ coupling between neighboring epithelial cells.

81)

______

A)

transcellular : tight junctional

B)

paracellular : tight junctional

C)

transcellular : gap junctional

D)

transcellular : desmosomal

E)

paracellular : gap junctional
Definition
B)

paracellular : tight junctional
Term
The movement of a number of molecules across the apical surface of the epithelial cell by secondary transporters is coupled to the ________ gradient that is maintained by the ________ on the basolateral surface of the epithelial cell.

82)

______

A)

Na+ : Na+ channel

B)

K+ : K+pump

C)

Ca2+ : Na+/K+ pump

D)

K+ : K+ channel

E)

Na+ : Na+/K+ pump
Definition
E)

Na+ : Na+/K+ pump


Term
Which of the following nervous system components is NOT a part of the peripheral nervous system?

83)

______

A)

the somatic nervous system

B)

the autonomic nervous system

C)

the sympathetic nervous system

D)

the enteric nervous system

E)

the parasympathetic nervous system
Definition
D)

the enteric nervous system
Term
A secondary endocrine organ is ________.

84)

______

A)

an organ that secretes tropic hormones

B)

an organ that secretes hormones, but is better known for another function

C)

an organ that is the target of tropic hormones

D)

an organ that receives communication from at least two hormones

E)

an organ that secretes at least two hormones
Definition
B)

an organ that secretes hormones, but is better known for another function
Term
In chemical communication between cells, a ________ cell secretes a chemical messenger that binds to ________ on the ________ cell.

85)

______

A)

gap : connexons : secretory

B)

secretory : connexons : target

C)

secretory : receptors : target

D)

secretory : connexons : gap

E)

target : receptors : secretory
Definition
C)

secretory : receptors : target
Term
In chemical communication between cells, a ________ cell secretes a chemical messenger that binds to ________ on the ________ cell.

86)

______

A)

gap : connexons : secretory

B)

secretory : connexons : target

C)

secretory : connexons : gap

D)

target : receptors : secretory

E)

secretory : receptors : target
Definition
E)

secretory : receptors : target
Term
Direct communication between cells in contact with one another is accomplished through ________.

87)

______

A)

ligands

B)

endocrine hormones

C)

receptors

D)

paracrine chemical messengers

E)

gap junctions
Definition
E)

gap junctions


Term
Which type of chemical messenger, when released, binds to receptors on the cell that released the chemical messenger?

88)

______

A)

neurotransmitter

B)

paracrine

C)

cytokine

D)

hormone

E)

autocrine
Definition
E)

autocrine
Term
Which type of chemical messenger is released into the bloodstream by an endocrine gland where it can affect target cells throughout the body?

89)

______

A)

cytokine

B)

hormone

C)

paracrine

D)

autocrine

E)

neurotransmitter
Definition
B)

hormone
Term
Which type of chemical messenger is released from the axon terminal of a neuron and directly communicates with other cells?

90)

______

A)

autocrine

B)

neurotransmitter

C)

paracrine

D)

cytokine

E)

hormone
Definition
B)

neurotransmitter
Term
Communication across a synapse is initiated by the release of a neurotransmitter from the ________ region of the neuron.

91)

______

A)

perisynaptic

B)

axon terminal

C)

dendritic

D)

postsynaptic

E)

axon hillock
Definition
B)

axon terminal
Term
Vasopressin (antidiuretic hormone), which is released from the posterior pituitary, is an example of this type of chemical messenger.

92)

______

A)

paracrine

B)

autocrine

C)

neurotransmitter

D)

neurohormone

E)

cytokine
Definition
D)

neurohormone
Term
Interleukins and interferons are examples of ________ released from white blood cells.

93)

______

A)

paracrines

B)

hormones

C)

cytokines

D)

autocrines

E)

neurotransmitters
Definition
C)

cytokines
Term
Which of the following classes of chemical messengers moves to the target cell by diffusion?

94)

______

A)

both paracrine and neurotransmitter

B)

hormone only

C)

both hormone and neurotransmitter

D)

paracrine only

E)

neurotransmitter only
Definition
A)

both paracrine and neurotransmitter
Term
Which of the following classes of chemical messengers travels in the bloodstream to the target cell?

95)

______

A)

hormone only

B)

both hormone and neurotransmitter

C)

both paracrine and neurotransmitter

D)

neurotransmitter only

E)

paracrine only
Definition
A)

hormone only
Term
Which of the following chemical messengers is lipophilic?

96)

______

A)

prostaglandin

B)

histamine

C)

norepinephrine

D)

glutamate

E)

gamma-amino butyric acid
Definition
A)

prostaglandin
Term
Which of the following chemical messengers is lipophilic and is therefore able to cross the cell membrane?

97)

______

A)

peptides

B)

eicosanoids

C)

proteins

D)

amino acids

E)

amines (excluding thyroid hormone
Definition
B)

eicosanoids
Term
Histamine acts as a(n) ________ in its role in inflammation.

98)

______

A)

autocrine

B)

paracrine

C)

hormone

D)

cytokine

E)

neurotransmitter
Definition
B)

paracrine
Term
Which of the following chemical messengers is NOT derived from an amino acid?

99)

______

A)

serotonin

B)

epinephrine

C)

thyroid hormones

D)

testosterone

E)

histamine
Definition
D)

testosterone
Term
All the messengers function as hormones for which of the following chemical classes?

100)

_____

A)

steroids

B)

amino acids

C)

eicosanoids

D)

amines

E)

peptides/proteins
Definition
A)

steroids
Term
All the messengers function as neurotransmitters for which of the following chemical classes?

101)

_____

A)

amines

B)

eicosanoids

C)

amino acids

D)

peptides/proteins

E)

steroids
Definition
C)

amino acids
Term
In order to convert the amino acid glutamate to gamma-amino butyric acid, cells must produce the enzyme ________ that catalyzes this reaction.

102)

_____

A)

glutamic acid dehydrogenase

B)

glutamic acid phosphorylase

C)

glutamic acid hydroxylase

D)

glutamic acid decarboxylase

E)

glutamate hydrolase
Definition
D)

glutamic acid decarboxylase
Term
The body is able to synthesize the amino acids glutamate, aspartate, and glycine from ________.

103)

_____

A)

the glycerol in a triglyceride

B)

the degradation of glucose in glycolysis and the Krebs cycle

C)

essential amino acids

D)

cholesterol

E)

the degradation of fatty acids
Definition
B)

the degradation of glucose in glycolysis and the Krebs cycle
Term
Cells that secrete dopamine must contain which of the following enzymes?

104)

_____

A)

dopamine β-hydroxylase only

B)

both dopamine β-hydroxylase and dopa decarboxylase

C)

tyrosine β-hydroxylase only

D)

dopa decarboxylase only

E)

both dopa decarboxylase and tryosine β-hydroxylase
Definition
E)

both dopa decarboxylase and tryosine β-hydroxylase

Term
Cells that secrete dopamine must contain which enzymes?

105)

_____

A)

tyrosine β-hydroxylase and dopa decarboxylase

B)

dopamine β-hydroxylase

C)

dopa decarboxylase

D)

dopamine β-hydroxylase and dopa decarboxylase

E)

tyrosine β-hydroxylase
Definition
A)

tyrosine β-hydroxylase and dopa decarboxylase
Term
Cells that secrete epinephrine must contain which enzymes?

106)

_____

A)

dopamine β-hydroxylase, tyrosine β-hydroxylase, phenylethanolamine N-methyl transferase, and dopa decarboxylase

B)

tyrosine β-hydroxylase and phenylethanolamine N-methyl transferase

C)

dopamine β-hydroxylase, tyrosine β-hydroxylase, and dopa decarboxylase

D)

phenylethanolamine N-methyl transferase and dopa decarboxylase

E)

dopamine β-hydroxylase and dopa decarboxylase


Definition
A)

dopamine β-hydroxylase, tyrosine β-hydroxylase, phenylethanolamine N-methyl transferase, and dopa decarboxylase
Term
Catecholamines are derived from what amino acid?

107)

_____

A)

glycine

B)

glutamate

C)

tyrosine

D)

tryptophan

E)

histidine
Definition
C)

tyrosine
Term
Thyroid hormones are synthesized from what amino acid?

108)

_____

A)

histidine

B)

tyrosine

C)

glutamate

D)

tryptophan

E)

glycine
Definition
B)

tyrosine
Term
Peptide/protein messengers are translated from ribosomes ________.

109)

_____

A)

attached to the nuclear envelope

B)

free in the cytosol

C)

attached to the rough endoplasmic reticulum

D)

attached to the smooth endoplasmic reticulum

E)

attached to the Golgi apparatus
Definition
C)

attached to the rough endoplasmic reticulum
Term
While in the rough endoplasmic reticulum, the initial polypeptide formed during protein synthesis is called a(n) ________.

110)

_____

A)

exon

B)

prepropeptide

C)

peptide

D)

prepeptide

E)

propeptide
Definition
B)

prepropeptide
Term
Once a steroid is synthesized, it is ________.

111)

_____

A)

stored in a vesicle until released

B)

stored in a unique protein structure that maintains steroids in the cell

C)

bound to the mitochondria until released

D)

immediately capable of diffusing across the membrane

E)

bound to albumin until released from the cell
Definition
D)

immediately capable of diffusing across the membrane
Term
Where in a cell are peptide/protein messengers packaged into secretory vesicles?

112)

_____

A)

rough endoplasmic reticulum

B)

nucleus

C)

lysosomes

D)

smooth endoplasmic reticulum

E)

Golgi apparatus


Definition
E)

Golgi apparatus
Term
________ is an enzyme that, when activated, will directly release arachidonic acid from a membrane phospholipid.

113)

_____

A)

Phospholipase A2

B)

Protein kinase A

C)

Phospholipase D

D)

Phospholipase C

E)

Protein kinase C
Definition
A)

Phospholipase A2
Term
In order to synthesize eicosanoids, ________ catalyzes the release of ________ from a membrane phospholipid.

114)

_____

A)

phospholipase A2 : cholesterol

B)

phospholipase A2 : arachidonic acid

C)

phospholipase C : inositol biphosphate

D)

phospholipase C : cholesterol

E)

phospholipase C : arachidonic acid
Definition
B)

phospholipase A2 : arachidonic acid
Term
An equilibrium exists between a hormone that is bound to a carrier protein and a free hormone such that, as the amount of free hormone increases, ________.

115)

_____

A)

the amount of bound hormone will not change

B)

cells will be stimulated to secrete more free hormone

C)

more free hormone will become bound to carrier proteins

D)

more bound hormone will be released from its carrier proteins

E)

more hormone must be synthesized to directly replace the free hormones


Definition
C)

more free hormone will become bound to carrier proteins
Term
Lipophilic chemical messengers are poorly soluble in water. However, many of these lipophilic messengers are transported throughout the body. Their transport in blood (water) is facilitated by ________.

116)

_____

A)

carrier proteins

B)

lipoproteins

C)

white blood cells

D)

red blood cells

E)

chylomicrons
Definition
A)

carrier proteins
Term
What enzyme catalyzes synthesis of prostaglandins from arachidonic acid?

117)

_____

A)

tyrosine β-hydroxylase

B)

phospholipase C

C)

lipoxygenase

D)

cyclooxygenase

E)

phospholipase A2
Definition
D)

cyclooxygenase
Term
Androgens are precursor molecules for the synthesis of ________.

118)

_____

A)

aldosterone

B)

estradiol

C)

cholesterol

D)

cortisol

E)

progesterone
Definition
B)

estradiol
Term
Progesterone is a precursor for the synthesis of ________.

119)

_____

A)

testosterone

B)

estradiol

C)

androstenedione

D)

dehydroepiandrosterone

E)

cortisol
Definition
E)

cortisol
Term
Aspirin decreases inflammation by inhibiting the actions of what enzyme?

120)

_____

A)

lipoxygenase

B)

protein kinase A

C)

cyclooxygenase

D)

phospholipase A2

E)

dopa decarboxylase
Definition
C)

cyclooxygenase
Term
Hormones that are dissolved in blood typically exhibit a half-life on the order of ________, whereas hormones that are bound to carrier proteins can remain undegraded for ________.

121)

_____

A)

seconds : hours

B)

minutes : hours

C)

seconds : minutes

D)

minutes : seconds

E)

hours : minutes
Definition
B)

minutes : hours
Term
The β1 adrenergic receptor has the greatest affinity for ________.

122)

_____

A)

epinephrine

B)

dopamine

C)

norepinephrine

D)

serotonin

E)

epinephrine and norepinephrine equally
Definition
E)

epinephrine and norepinephrine equally


Term
The α1 adrenergic receptor has the greatest affinity for ________.

123)

_____

A)

serotonin

B)

dopamine

C)

norepinephrine

D)

epinephrine

E)

epinephrine and norepinephrine equally
Definition
C)

norepinephrine
Term
Which of the following will NOT affect the magnitude of a cell's response to a specific hydrophilic ligand?

124)

_____

A)

affinity of the receptor for the ligand

B)

number of receptors

C)

receptor upregulation

D)

lipid solubility of the ligand

E)

ligand concentration
Definition
D)

lipid solubility of the ligand
Term
Chronic exposure to a ligand (messenger) ________ the receptor population for that chemical messenger on the target cell.

125)

_____

A)

decreases the specificity of

B)

changes the conformation of

C)

decreases the affinity of

D)

upregulates

E)

downregulates
Definition
E)

downregulates
Term
Which of the following statements best describes the release of lipophobic messengers?

126)

_____

A)

Lipophobic messengers are stored in vesicles and released by exocytosis in response to a stimulus.

B)

Lipophobic messengers are stored in vesicles and released by exocytosis immediately after synthesis.

C)

Lipophobic messengers are stored in vesicles and released by simple diffusion in response to a stimulus.

D)

Lipophobic messengers are stored free in the cytosol and released by simple diffusion in response to a stimulus.

E)

Lipophobic messengers are released immediately upon synthesis by simple diffusion.


Definition
A)

Lipophobic messengers are stored in vesicles and released by exocytosis in response to a stimulus.
Term
Which of the following statements best describes the release of a lipophilic messenger?

127)

_____

A)

Lipophilic messengers are stored in vesicles and released by simple diffusion in response to a stimulus.

B)

Lipophilic messengers are stored in vesicles and released by exocytosis in response to a stimulus.

C)

Lipophilic messengers are stored free in the cytosol and released by simple diffusion in response to a stimulus.

D)

Lipophilic messengers are released immediately upon synthesis by simple diffusion.

E)

Lipophilic messengers are stored in vesicles and released by exocytosis immediately after synthesis.

Definition
D)

Lipophilic messengers are released immediately upon synthesis by simple diffusion
Term
)

Lipophilic hormones are transported in blood ________ and bind to receptors located ________.

128)

_____

A)

bound to carrier proteins : inside the target cell

B)

dissolved in the plasma : on the plasma membrane of the target cell

C)

dissolved in the plasma : inside the target cell

D)

bound to carrier proteins : on the plasma membrane of the target cell

E)

inside red blood cells : inside the target cell
Definition
A)

bound to carrier proteins : inside the target cell
Term
A molecule that is similar in structure to a ligand (messenger) and binds with that ligand's receptor to stimulate a response from the target cell is called a(n) ________.

129)

_____

A)

blocker

B)

synergist

C)

agonist

D)

antagonist

E)

protagonist
Definition
C)

agonist
Term
The ________ is the portion of a gene that is capable of being bound by a particular hormone-receptor complex that can stimulate alterations in that gene's expression.

130)

_____

A)

intron

B)

exon

C)

hormone response element

D)

promoter

E)

nuclear receptor
Definition
C)

hormone response element
Term
The affinity of a receptor for its ligand is a measure of ________.

131)

_____

A)

the ability of the ligand to permeate the plasma membrane and reach its receptor

B)

the percent of receptors on a specific target cell with bound ligand

C)

the response produced in the target cell when the ligand binds to the receptor

D)

the strength of binding between ligand and receptor

E)

the number of binding sites available for the ligand
Definition
D)

the strength of binding between ligand and receptor
Term
Typical responses to ________ messengers require a long time to develop because they necessitate transcription of mRNA and translation of that mRNA into a functional protein.

132)

_____

A)

peptide

B)

amino acid

C)

lipophilic

D)

lipophobic

E)

protein
Definition
C)

lipophilic
Term
________ describe ion channels that are coupled to membrane receptors such that their gating properties (opening and closing) are altered by messenger binding.

133)

_____

A)

Enzyme-linked receptors

B)

Voltage-gated channels

C)

G protein-linked channels

D)

Potential-gated channels

E)

Ligand-gated channels
Definition
E)

Ligand-gated channels


Term
Slow channels are identified as such because, once the receptor is bound by the ligand, the receptor must directly activate a(n) ________.

134)

_____

A)

RNA polymerase

B)

ion channel

C)

hormone response element

D)

enzyme

E)

G protein
Definition
E)

G protein
Term
Differences in the rate of activity between fast and slow ligand-gated channels is caused by ________.

135)

_____

A)

ligand selectivity

B)

ligands gating both channels to the closed state

C)

G protein activity gating the fast channel

D)

ligand affinity

E)

G protein activity gating the slow channel
Definition
E)

G protein activity gating the slow channel


Term
Which of the following ions can act as a second messenger?

136)

_____

A)

sodium only

B)

calcium only

C)

both sodium and potassium

D)

potassium only

E)

both sodium and calcium
Definition
B)

calcium only
Term
Opening channels for which of the following ions can trigger exocytosis?

137)

_____

A)

chloride

B)

sodium

C)

potassium

D)

magnesium

E)

calcium
Definition
E)

calcium
Term
Which of the following ions binds to calmodulin to ultimately activate a protein kinase?

138)

_____

A)

potassium

B)

chloride

C)

calcium

D)

sodium

E)

magnesium
Definition
C)

calcium
Term
Binding of acetylcholine to a nicotinic receptor on skeletal muscle will lead directly to a ________ at the cell membrane.

139)

_____

A)

slow influx of Na+ through its channel and rapid outward flux of K+

B)

rapid influx of Na+ through its channel and no movement of K+

C)

rapid influx of Na+ and slow outward flux of K+

D)

rapid influx of K+ through its channel and no movement of Na+

E)

fast influx of Na+ and K+ through its channel
Definition
C)

rapid influx of Na+ and slow outward flux of K+
Term
In its role as a ________, calcium is observed to bind to ________ that, when complexed, provides for the activation of a protein kinase.

140)

_____

A)

first messenger : a protein kinase

B)

first messenger : a hydrolase

C)

second messenger : a phosphatase

D)

third messenger : calmodulin

E)

second messenger : calmodulin
Definition
E)

second messenger : calmodulin


Term
Which of the following statements best describes the function of tyrosine kinase?

141)

_____

A)

It catalyzes the phosphorylation of a protein inside a cell.

B)

It catalyzes the formation of norepinephrine from dopamine.

C)

It catalyzes the phosphorylation of a protein in the extracellular fluid.

D)

It sequesters calcium in the cytosol.

E)

It catalyzes the formation of dopamine from L-dopa
Definition
A)

It catalyzes the phosphorylation of a protein inside a cell.
Term
Which of the following is NOT an integral membrane protein?

142)

_____

A)

tyrosine kinase

B)

phospholipase C

C)

G proteins

D)

adenylate cyclase

E)

calmodulin
Definition
E)

calmodulin
Term
Which of the following enzymes directly covalently modulates a protein?

143)

_____

A)

tyrosine β-hydroxylase

B)

phospholipase C

C)

phosphodiesterase

D)

tyrosine kinase

E)

adenylate cyclase
Definition
D)

tyrosine kinase
Term
The function of a second messenger is to ________.

144)

_____

A)

amplify the response of the first messenger

B)

isolate the response to the inside of a cell

C)

keep calcium involved in these responses

D)

buffer a cells response to a ligand

E)

facilitate the process of covalent modification of a protein


Definition
A)

amplify the response of the first messenger
Term
Which of the following is NOT a process whereby calcium is functionally removed from the cytosol of a cell?

145)

_____

A)

sequestration of calcium by proteins within the cytosol

B)

active pumping of calcium across the plasma membrane

C)

active transport of calcium into the mitochondria

D)

active transport of calcium into the smooth endoplasmic reticulum

E)

sequestration of calcium within the Golgi apparatus


Definition
E)

sequestration of calcium within the Golgi apparatus
Term
In its active form, a G protein will have ________.

146)

_____

A)

the alpha subunit separated from the gamma and beta subunit

B)

the gamma subunit separated from the alpha and beta subunit

C)

the beta subunit separated from the alpha and gamma subunit

D)

the alpha and beta subunit separated from the gamma subunit

E)

the alpha and gamma subunit separated from the beta subunit


Definition
A)

the alpha subunit separated from the gamma and beta subunit
Term
When the alpha subunit of the G protein is activated, it can stimulate ion channels to ________.

147)

_____

A)

degrade

B)

alter the ion that travels through the channel

C)

close only

D)

either open or close

E)

open only
Definition
D)

either open or close
Term
The enzyme that catalyzes synthesis of cAMP is called ________ and is activated by ________.

148)

_____

A)

phosphoprotein phosphatase : a Gi protein

B)

phosphodiesterase : a Gs protein

C)

phosphodiesterase : a Gi protein

D)

adenylate cyclase : a Gi protein

E)

adenylate cyclase : a Gs protein
Definition
E)

adenylate cyclase : a Gs protein


Term
What enzyme is activated by cAMP?

149)

_____

A)

tyrosine kinase

B)

protein kinase C

C)

phosphodiesterase

D)

protein kinase A

E)

adenylate cyclase
Definition
D)

protein kinase A
Term
What type of enzyme removes the phosphate group from a covalently modulated protein?

150)

_____

A)

phosphodiesterase

B)

protein kinase

C)

tyrosine kinase

D)

phospholipase

E)

phosphoprotein phosphatase
Definition
E)

phosphoprotein phosphatase
Term
In order to terminate a cAMP-mediated response, the enzyme ________ can be activated to degrade cAMP.

151)

_____

A)

cAMP decarboxylase

B)

cAMP phosphodiesterase

C)

cAMP protein kinase

D)

cAMP hydrolase

E)

cAMP hydrogenase
Definition
B)

cAMP phosphodiesterase
Term
When associated with G protein, guanylate cyclase will activate the enzyme ________ .

152)

_____

A)

phospholipase C

B)

protein kinase G

C)

phosphodiesterase

D)

protein kinase C

E)

protein kinase A
Definition
B)

protein kinase G
Term
Which of the following second messengers, when released by phospholipase C, will directly activate the enzyme protein kinase C?

153)

_____

A)

inositol biphosphate

B)

phosphatidylinositol biphosphate

C)

inositol triphosphate

D)

cGMP

E)

diacylglycerol
Definition
E)

diacylglycerol
Term
________, when formed by phospholipase C, triggers the release of calcium from the endoplasmic reticulum.

154)

_____

A)

Diacylglycerol

B)

Phosphatidylinositol biphosphate

C)

Inositol triphosphate

D)

Inositol biphosphate

E)

cGMP
Definition
C)

Inositol triphosphate
Term
Which of the following proteins is directly activated by a G protein?

155)

_____

A)

tyrosine kinase

B)

protein kinase G

C)

phospholipase A2

D)

calmodulin

E)

adenylate cyclase
Definition
E)

adenylate cyclase
Term
What is phosphatidylinositol-4,5-biphosphate?

156)

_____

A)

a component of a G protein

B)

an enzyme that catalyzes degradation of a second messenger

C)

a second messenger

D)

a phospholipid in plasma membranes

E)

an enzyme that catalyzes formation of a second messenger


Definition
D)

a phospholipid in plasma membranes
Term
Which of the following describes the signal transduction mechanism for estrogen, a steroid hormone?

157)

_____

A)

activation of cAMP second messenger system

B)

opening of fast ligand-gated channels

C)

activation of enzyme-linked receptor

D)

altering transcription of mRNA

E)

opening or closing of fast ligand-gated channels
Definition
D)

altering transcription of mRNA
Term
Which of the following is a second messenger?

158)

_____

A)

cAMP, calcium, and inositol triphosphate

B)

inositol triphosphate only

C)

both cAMP and inositol triphosphate

D)

calcium only

E)

cAMP only
Definition
A)

cAMP, calcium, and inositol triphosphate
Term
Which of the following statements is true for the nervous system but NOT the endocrine system?

159)

_____

A)

Effector organs are scattered throughout the body.

B)

A messenger is transported in the bloodstream.

C)

There is a special anatomical arrangement between the secretory cell and the target cell.

D)

Communication occurs over long distances.

E)

A messenger communicates to target cells by binding to specific receptors
Definition
C)

There is a special anatomical arrangement between the secretory cell and the target cell
Term
Which of the following endocrine organs is located in the brain?

160)

_____

A)

pancreas

B)

adrenal gland

C)

thymus

D)

gonads

E)

hypothalamus


Definition
E)

hypothalamus
Term
The posterior lobe of the pituitary gland is also known as the ________.

161)

_____

A)

pineal gland

B)

adenohypophysis

C)

melanocyte

D)

neurohypophysis

E)

paraventricular nucleus


Definition
D)

neurohypophysis
Term
Vasopressin (antidiuretic hormone) is synthesized in the ________ nucleus located within the ________.

162)

_____

A)

supraoptic : hypothalamus

B)

supraoptic : posterior pituitary

C)

paraventricular : posterior pituitary

D)

paraventricular : anterior pituitary

E)

paraventricular : hypothalamus
Definition
E)

paraventricular : hypothalamus
Term
Oxytocin is synthesized in the ________ nucleus located within the ________.

163)

_____

A)

paraventricular : hypothalamus

B)

paraventricular : posterior pituitary

C)

supraoptic : posterior pituitary

D)

paraventricular : anterior pituitary

E)

supraoptic : hypothalamus
Definition
E)

supraoptic : hypothalamus
Term
________ is released by the posterior pituitary and functions in uterine contraction and milk letdown in the breast.

164)

_____

A)

Prolactin

B)

Antidiuretic hormone

C)

Vasopressin

D)

Somatomedin

E)

Oxytocin
Definition
E)

Oxytocin


Term
Secretion of hormones from the anterior pituitary is stimulated by ________ released from the ________.

165)

_____

A)

oxytocin : hypothalamus

B)

inhibiting hormones : posterior pituitary

C)

antidiuretic hormone : hypothalamus

D)

stimulating hormones : posterior pituitary

E)

releasing hormones : hypothalamus
Definition
E)

releasing hormones : hypothalamus


Term
The ________ ensure(s) that blood levels of a specific releasing hormone are locally high in order to stimulate the pituitary.

166)

_____

A)

pulsatility of tropic hormone release

B)

degradation rates of tropic hormones

C)

hepatic portal system

D)

affinity of the tropic hormones

E)

hypothalamic-pituitary portal system
Definition
E)

hypothalamic-pituitary portal system


Term
Which of the following is NOT a hormone released from the anterior pituitary?

167)

_____

A)

prolactin inhibiting hormone

B)

luteinizing hormone

C)

adrenocorticotropic hormone

D)

growth hormone

E)

follicle stimulating hormone
Definition
A)

prolactin inhibiting hormone
Term
Which tropic hormone is responsible for controlling the release of follicle stimulating hormone from the anterior pituitary?

168)

_____

A)

gonadotropin releasing hormone

B)

follicle stimulating releasing hormone

C)

thyrotropin releasing hormone

D)

corticotropin releasing hormone

E)

growth hormone releasing hormone
Definition
A)

gonadotropin releasing hormone
Term
Which of the following correctly describes a pathway for secretion of a hormone under the control of tropic hormones?

169)

_____

A)

GHRH stimulates GH release, which stimulates somatomedin release.

B)

TRH stimulates TSH release, which stimulates thymosin release.

C)

PRH stimulates PH release, which stimulates prolactin release.

D)

GnRH stimulates PH release, which stimulates prolactin release.

E)

CRH stimulates ACTH release, which stimulates somatomedin
Definition
A)

GHRH stimulates GH release, which stimulates somatomedin release
Term
Which of the following tropic hormones is a catecholamine?

170)

_____

A)

luteinizing hormone

B)

prolactin-inhibiting hormone

C)

growth hormone-inhibiting hormone

D)

prolactin-releasing hormone

E)

growth hormone
Definition
B)

prolactin-inhibiting hormone
Term
Which of the following is a correct example of long-loop negative feedback?

171)

_____

A)

Glucocorticoids inhibit the release of CRH.

B)

FSH inhibits the release of GnRH.

C)

TSH inhibits the release of TRH.

D)

TSH stimulates the release of TRH.

E)

GH stimulates the release of GHIH.
Definition
A)

Glucocorticoids inhibit the release of CRH
Term
Which of the following is a correct example of short-loop negative feedback?

172)

_____

A)

Thyroid hormones inhibit the release of TRH.

B)

TSH inhibits the release of TRH.

C)

TRH stimulates the release of thyroid hormones.

D)

Thyroid hormones inhibit the release of TSH.

E)

TRH inhibits the release of TSH.
Definition
B)

TSH inhibits the release of TRH
Term
The release of ________ from the pineal gland is important for establishing ________.

173)

_____

A)

prolactin : breast milk production

B)

melatonin : circadian rhythm

C)

prolactin : circadian rhythm

D)

melatonin : thirst

E)

melanin : thirst
Definition
B)

melatonin : circadian rhythm
Term
The thyroid gland secretes what hormone?

174)

_____

A)

both thyroid hormones and calcitonin

B)

both thyroid hormones and thymosin

C)

thyroid hormones only

D)

thymosin only

E)

calcitonin only
Definition
A)

both thyroid hormones and calcitonin
Term
What is triiodothyronine?

175)

_____

A)

a catecholamine released from the adrenal cortex

B)

a thyroid hormone

C)

a catecholamine released from the adrenal medulla

D)

the hormone secreted from the thymus

E)

the hormone secreted from the pineal gland
Definition
B)

a thyroid hormone
Term
Which of the following hormones is NOT released from the adrenal gland?

176)

_____

A)

cortisol

B)

epinephrine

C)

androgens

D)

aldosterone

E)

adrenocorticotropic hormone
Definition
E)

adrenocorticotropic hormone
Term
Which of the following hormones is NOT secreted by the endocrine region of the pancreas?

177)

_____

A)

somatostatin

B)

insulin

C)

glucagon

D)

glucocorticoids

E)

pancreatic polypeptide
Definition
D)

glucocorticoids
Term
What layer of the adrenal cortex secretes mineralocorticoids?

178)

_____

A)

zona glomerulosa only

B)

zona reticularis only

C)

both zonae reticularis and glomerulosa

D)

zona fasciculata only

E)

both zonae reticularis and fasciculata
Definition
zona glomerulosa only
Term
What layer of the adrenal cortex secretes androgens?

179)

_____

A)

both zonae reticularis and fasciculata

B)

zona fasciculata only

C)

zona reticularis only

D)

zona glomerulosa only

E)

both zonae reticularis and glomerulosa
Definition
A)

both zonae reticularis and fasciculata
Term
What region of the adrenal gland secretes epinephrine?

180)

_____

A)

zona fasciculata

B)

zonae reticularis, fasciculata, and glomerulosa

C)

zona reticularis

D)

medulla

E)

zona glomerulosa
Definition
D)

medulla
Term
What cells secrete epinephrine from the adrenal medulla?

181)

_____

A)

chromaffin cells

B)

B cells

C)

A cells

D)

zona reticularis cells

E)

D cells
Definition
A)

chromaffin cells
Term
Which of the following is the incorrect association between pancreatic cell type and hormone secreted?

182)

_____

A)

Epsilon cells secrete calcitonin.

B)

F cells secrete pancreatic polypeptide.

C)

Beta cells secrete insulin.

D)

Alpha cells secrete glucagon.

E)

Delta cells secrete somatostatin.
Definition
A)

Epsilon cells secrete calcitonin
Term
Which of the following hormones is NOT secreted by gonads?

183)

_____

A)

estradiol

B)

progesterone

C)

oxytocin

D)

testosterone

E)

androstenedione
Definition
C)

oxytocin
Term
What anterior pituitary hormone is NOT a tropic hormone?

184)

_____

A)

luteinizing hormone

B)

growth hormone

C)

prolactin

D)

follicle stimulating hormone

E)

adrenocorticotropic hormone
Definition
C)

prolactin
Term
Which of the following hormones regulates plasma calcium levels?

185)

_____

A)

both calcitonin and parathyroid hormone

B)

calcitonin only

C)

oxytocin only

D)

parathyroid hormone only

E)

both calcitonin and oxytocin
Definition
A)

both calcitonin and parathyroid hormone
Term
What hormone is secreted by the heart?

186)

_____

A)

thymosin

B)

somatostatin

C)

atrial natriuretic peptide

D)

erythropoietin

E)

epinephrine
Definition
C)

atrial natriuretic peptide
Term
The neural input for circadian rhythmicity of hypothalamic tropic hormones originates from the ________.

187)

_____

A)

paraventricular nucleus

B)

cerebrum

C)

supraoptic nucleus

D)

pineal gland

E)

suprachiasmatic nucleus
Definition
E)

suprachiasmatic nucleus
Term
Once bound to a receptor on the cell membrane, some hormones are ________ only to be ________ by lysosomes.

188)

_____

A)

activated : stabilized

B)

inactivated : stabilized

C)

internalized : degraded

D)

externalized : degraded

E)

presented : degraded
Definition
C)

internalized : degraded
Term
Abnormal hormone secretions from an endocrine gland due to altered tropic hormone release are called ________.

189)

_____

A)

hypersecretions

B)

primary secretion disorders

C)

tertiary secretion disorders

D)

secondary secretion disorders

E)

hyposecretions
Definition
D)

secondary secretion disorders
Term
Which of the following changes in plasma levels would be observed in a primary hyposecretion of cortisol?

190)

_____

A)

decreased CRH, decreased ACTH, and increased cortisol

B)

decreased CRH, decreased ACTH, and decreased cortisol

C)

increased CRH, increased ACTH, and increased cortisol

D)

increased CRH, decreased ACTH, and decreased cortisol

E)

increased CRH, increased ACTH, and decreased cortisol


Definition
E)

increased CRH, increased ACTH, and decreased cortisol


Term
A person has a tumor in the hypothalamus causing an excess in TRH secretion. Which of the following correctly describes changes in plasma levels of hormones?

191)

_____

A)

decreased TRH, decreased TSH, and decreased thyroid hormones

B)

increased TRH, increased TSH, and decreased thyroid hormones

C)

decreased TRH, decreased TSH, and increased thyroid hormones

D)

increased TRH, increased TSH, and increased thyroid hormones

E)

increased TRH, decreased TSH, and decreased thyroid hormones


Definition
D)

increased TRH, increased TSH, and increased thyroid hormones
Term
A person has a tumor in the anterior pituitary causing a decrease in ACTH secretion. Which of the following correctly describes changes in plasma levels of hormones?

192)

_____

A)

decreased CRH, decreased ACTH, and increased cortisol

B)

decreased CRH, decreased ACTH, and decreased cortisol

C)

increased CRH, increased ACTH, and decreased cortisol

D)

increased CRH, decreased ACTH, and decreased cortisol

E)

increased CRH, increased ACTH, and increased cortisol
Definition
D)

increased CRH, decreased ACTH, and decreased cortisol
Term
When the response to two hormones is equal to the sum of their individual responses, the response is described as ________.

193)

_____

A)

agonistic

B)

permissive

C)

synergistic

D)

antagonized

E)

additive
Definition
E)

additive
Term
When the response to two hormones is greater than the sum of the individual responses, the response is described as ________.

194)

_____

A)

agonistic

B)

permissive

C)

additive

D)

synergistic

E)

antagonized
Definition
D)

synergistic
Term
Which of the following correctly lists the components of the central nervous system?

195)

_____

A)

brain and nerves

B)

brain, spinal cord, and nerves

C)

sympathetic and parasympathetic nervous system

D)

brain and spinal cord

E)

spinal cord and nerves
Definition
D)

brain and spinal cord
Term
Which of the following is located in the autonomic nervous system?

196)

_____

A)

parasympathetic nervous only

B)

both sympathetic and parasympathetic nervous systems

C)

both sympathetic and somatic nervous systems

D)

sympathetic nervous system only

E)

somatic nervous system only
Definition
B)

both sympathetic and parasympathetic nervous systems
Term
Which of the following accurately describes afferent neurons?

197)

_____

A)

They transmit information from the periphery to the CNS.

B)

They transmit information from the CNS to the periphery.

C)

They are typically multipolar neurons.

D)

They are the most abundant class of neurons.

E)

The cell body is located in teh ventral horn of the spinal cord
Definition
A)

They transmit information from the periphery to the CNS
Term
________ is/are the functional unit of the nervous system.

198)

_____

A)

Axons

B)

The brain

C)

Glial cells

D)

The central nervous system

E)

Neurons
Definition
E)

Neurons


Term
The ________ is the portion of the neuron along which the action potential propagates.

199)

_____

A)

dendrite

B)

axon

C)

soma

D)

cell body

E)

nucleus


Definition
B)

axon
Term
Information is transmitted from cell to cell across the chemical synapse via a(n) ________.

200)

_____

A)

action potential

B)

collateral potential

C)

neurosecretory hormone

D)

graded potential

E)

neurotransmitter
Definition
E)

neurotransmitter
Term
An action potential originates at the ________ and travels along the axon until it reaches the ________.

201)

_____

A)

axon hillock : axon terminal

B)

axon terminal : axon hillock

C)

dendrite : axon terminal

D)

dendrite : axon hillock

E)

axon hillock : dendrite
Definition
A)

axon hillock : axon terminal
Term
What type of ion channels in the membrane of neurons allow ions to move across the membrane at rest, and thereby contribute to resting membrane potential?

202)

_____

A)

resting channels

B)

ligand-gated channels

C)

voltage-gated channels

D)

leak channels

E)

potential-gated channels
Definition
D)

leak channels
Term
What type of ion channels in the membrane of neurons open or close in response to a neurotransmitter binding to its receptor?

203)

_____

A)

potential-gated channels

B)

voltage-gated channels

C)

ligand-gated channels

D)

leak channels

E)

synaptic channels
Definition
C)

ligand-gated channels
Term
In a neuron, where is the greatest concentration of voltage-gated sodium and voltage-gated potassium channels?

204)

_____

A)

dendrites

B)

axon hillock

C)

axon

D)

soma

E)

axon terminal
Definition
B)

axon hillock
Term
In a neuron, where are voltage-gated calcium channels located?

205)

_____

A)

soma

B)

axon hillock

C)

axon terminal

D)

axon

E)

dendrites
Definition
C)

axon terminal
Term
What is the structural classification of a neuron composed of a single axon and a number of dendritic projections from the nerve cell body?

206)

_____

A)

multipolar

B)

polar

C)

pseudo-unipolar

D)

unipolar

E)

bipolar


Definition
A)

multipolar
Term
Which of the following is a functional classification of neurons that, for the most part, are bipolar in structure and carry information from the peripheral axon to the central axon?

207)

_____

A)

efferent neurons

B)

interneurons

C)

multipolar cells

D)

afferent neurons

E)

bipolar cells
Definition
D)

afferent neurons
Term
Which of the following terms is NOT used to describe a bundle of axons in the central or peripheral nervous system?

208)

_____

A)

tracts

B)

nerves

C)

commissures

D)

pathways

E)

ganglia
Definition
E)

ganglia
Term
Which of the following cells is NOT classified as a glial cell?

209)

_____

A)

Schwann cell

B)

oligodendrocyte

C)

ventricular cell

D)

ependymal cell

E)

astrocyte
Definition
C)

ventricular cell
Term
What type of cell enhances the velocity of electrical transmission of an action potential along an axon in the central nervous system?

210)

_____

A)

astrocyte

B)

microglia

C)

oligodendrocyte

D)

Schwann cell

E)

ependymal cell
Definition
C)

oligodendrocyte
Term
The myelin sheath that coats an axon acts to ________.

211)

_____

A)

decrease ion permeability in the nodes of Ranvier

B)

reduce a membrane's ion permeability

C)

increase a membrane's ion permeability

D)

decrease axonal conduction velocity

E)

increase leakage of ions across the membrane
Definition
B)

reduce a membrane's ion permeability
Term
The movement of an electrical charge across a membrane describes ________.

212)

_____

A)

a potential difference

B)

a capacitance

C)

a current

D)

a transistor

E)

a resistance
Definition
C)

a current
Term
The resistance to an ion's movement across a membrane is determined by ________.

213)

_____

A)

the ions present on either side of the membrane

B)

receptors on the cell membrane

C)

enzymes on the surface of the cell membrane

D)

ion channels within the membrane

E)

the resting membrane potential
Definition
D)

ion channels within the membrane
Term
The inverse of resistance is ________.

214)

_____

A)

impedance

B)

current

C)

flux

D)

voltage

E)

conductance
Definition
E)

conductance


Term
Which of the following is NOT a factor involved in the determination of resting membrane potential?

215)

_____

A)

presence of potassium channels

B)

concentration of sodium receptors

C)

concentration of potassium

D)

presence of sodium channels

E)

concentration of sodium
Definition
B)

concentration of sodium receptors
Term
Which of the following statements about sodium is FALSE?

216)

_____

A)

There is a chemical force driving sodium ions into the cell.

B)

At the resting membrane potential, there is an electrical force driving sodium ions into the cell.

C)

At the potassium equilibrium potential, there is an electrical force driving sodium ions out of the cell.

D)

At the sodium equilibrium potential, the electrochemical force for sodium movement across the plasma membrane is zero.

E)

At the sodium equilibrium potential, there is an electrical force driving sodium ions out of the cell.
Definition
C)

At the potassium equilibrium potential, there is an electrical force driving sodium ions out of the cell.
Term
Which of the following best describes the electrochemical forces acting on sodium and potassium ions at the resting membrane potential?

217)

_____

A)

Forces on both sodium and potassium ions are to move out of the cell.

B)

The force on sodium ions is to move into the cell, and the force on potassium ions is to move out of the cell.

C)

The force on sodium ions is to move out of the cell, and the force on potassium ions is to move into the cell.

D)

There is no force on either ion to move.

E)

Forces on both sodium and potassium ions are to move into the cell
Definition
B)

The force on sodium ions is to move into the cell, and the force on potassium ions is to move out of the cell.
Term
Given a cation with an equilibrium potential of -55 mV. If the plasma membrane of the cell is permeable only to this ion, then which of the following best describes the resting membrane potential?

218)

_____

A)

-70 mV

B)

-55 mV

C)

+55 mV

D)

More negative than -55 mV

E)

More positive than -55 mV
Definition
B)

-55 mV
Term
At the resting membrane potential, the membrane is most permeable to ________, which moves ________ the cell due to its electrochemical gradient.

219)

_____

A)

chloride : into

B)

sodium : into

C)

potassium : out of

D)

potassium : into

E)

sodium : out of
Definition
C)

potassium : out of
Term
The electrochemical gradient for sodium across the membrane is such that the net flux of sodium will be ________, thereby causing the cell's membrane potential to become more ________.

220)

_____

A)

outward : negative

B)

inward : negative

C)

outward : positive

D)

inward : positive

E)

at equilibrium : positive
Definition
D)

inward : positive
Term
The membrane potential at which there is no net flux of an ion across the membrane is called that ion's ________.

221)

_____

A)

potential difference

B)

equilibrium potential

C)

resting membrane potential

D)

graded potential

E)

action potential
Definition
B)

equilibrium potential
Term
The presence of the ________ prevents the dissipation of the concentration gradient for Na+.

222)

_____

A)

equilibrium potential

B)

Na+/H+ antiporter

C)

Na+/Ca2+ exchanger

D)

action potential

E)

Na+/K+ pump
Definition
E)

Na+/K+ pump


Term
The Na+/K+ pump is called an electrogenic pump because the imbalance between ________.

223)

_____

A)

Na+ out to K+ in leaves the inside of the cell with a net negative charge

B)

ATP utilization inside the cell relative to the outside

C)

Na+ out to K+ in leaves the inside of the cell with a net positive charge

D)

Na+ in to K+ out leaves the inside of the cell with a net negative charge

E)

Na+ in to K+ out leaves the inside of the cell with a net positive charge


Definition
A)

Na+ out to K+ in leaves the inside of the cell with a net negative charge
Term
The electrical potential of a membrane at rest is closest to potassium's equilibrium potential because ________.

224)

_____

A)

more sodium channels are open, allowing more sodium to move into the cell

B)

more potassium channels are open, allowing more potassium to move into the cell

C)

more sodium channels are open, allowing more sodium to move out of the cell

D)

more potassium channels are open, allowing more potassium to move out of the cell

E)

all potassium channels are open
Definition
D)

more potassium channels are open, allowing more potassium to move out of the cell
Term
If, under resting conditions, the membrane is much more permeable to sodium than potassium, resting membrane potential would ________.

225)

_____

A)

be altered very little

B)

approach potassium's equilibrium potential

C)

become more negative

D)

approach sodium's equilibrium potential

E)

approach chloride's equilibrium potential
Definition
D)

approach sodium's equilibrium potential
Term
As a membrane's permeability to a particular ion increases, membrane potential will move ________ that ion's ________.

226)

_____

A)

away from : electrochemical gradient

B)

away from : electrical gradient

C)

closer to : equilibrium potential

D)

closer to : electrochemical gradient

E)

away from : equilibrium potential
Definition
C)

closer to : equilibrium potential
Term
Membrane permeability is altered in the short term (seconds) by changes in the ________ of ion channels.

227)

_____

A)

formation

B)

cleavage

C)

degradation

D)

gating

E)

production
Definition
D)

gating
Term
Closure of an ion channel will increase a cell membrane's ________, whereas ________ will decrease.

228)

_____

A)

permeability : conductance

B)

permeability : resistance

C)

conductance : resistance

D)

electrical current : permeability

E)

resistance : conductance
Definition
E)

resistance : conductance


Term
The opening of an ion channel increases a cell membrane's ________, whereas ________ will decrease.

229)

_____

A)

conductance : resistance

B)

resistance : permeability

C)

permeability : conductance

D)

permeability : electrical current

E)

resistance : conductance
Definition
A)

conductance : resistance
Term
The fact that a cell has an electrical potential difference across its membrane makes that cell ________.

230)

_____

A)

polarized

B)

polar

C)

hyperpolarized

D)

repolarized

E)

depolarized
Definition
A)

polarized
Term
A change in a cell's membrane potential, such that it becomes more positive, is referred to as a ________.

231)

_____

A)

polarization

B)

repolarization

C)

hypopolarization

D)

hyperpolarization

E)

depolarization
Definition
E)

depolarization


Term
A change in a cell's membrane potential, such that it becomes more negative, is referred to as a ________.

232)

_____

A)

depolarization

B)

polarization

C)

hyperpolarization

D)

hypopolarization

E)

repolarization
Definition
C)

hyperpolarization
Term
A ________ is a subthreshold change in membrane potential within the cell body that decays as it travels away from its point of origin.

233)

_____

A)

hyperpolarization

B)

action potential

C)

depolarization

D)

polarization

E)

graded potential
Definition
E)

graded potential


Term
The direction of change in membrane potential, in response to a stimulus that initiates a graded potential, is dependent upon ________.

234)

_____

A)

that membrane's threshold potential

B)

the ion channels that are opened or closed

C)

the gating of sodium channels only

D)

the changes in ion concentration across the membrane

E)

the gating of potassium channels only
Definition
B)

the ion channels that are opened or closed
Term
Which of the following does NOT produce graded potentials?

235)

_____

A)

the release of a neurotransmitter onto a cell body

B)

light impinging on a photoreceptor

C)

arrival of a suprathreshold stimulus at the axon hillock

D)

touching a sensory receptor

E)

the release of a neurotransmitter onto a dendrite
Definition
Term
C)

arrival of a suprathreshold stimulus at the axon hillock
Definition
C)

arrival of a suprathreshold stimulus at the axon hillock
Term
Which of the following statements is FALSE?

236)

_____

A)

Graded potentials and action potentials are caused by ions moving through channels.

B)

Graded potentials and action potentials are all-or-none.

C)

Graded potentials and action potentials can change the membrane potential of adjacent areas of the membrane through electrotonic conduction.

D)

Graded potentials do not have refractory periods, but action potentials do.

E)

Graded potentials can sum over time but action potentials cannot.


Definition
B)

Graded potentials and action potentials are all-or-none
Term
The ________ in graded potential that occurs as current spreads along the membrane happens as a consequence of the ________ of current across the membrane.

237)

_____

A)

decrement : leakage

B)

elevation : blockade

C)

decrement : blockade

D)

elevation : leakage

E)

elevation : generation
Definition
A)

decrement : leakage
Term
Which of the following is an example of spatial summation?

238)

_____

A)

A neuron sends out information through collaterals to several target cells.

B)

An action potential occurs at the same time as a graded potential, and they sum.

C)

Two action potentials occur at the same time and sum.

D)

Two stimuli from two sources produce graded potentials on the same neuron at the same time such that the two potentials sum.

E)

Two rapid stimuli from the same source produce graded potentials on the neuron that sum.
Definition
D)

Two stimuli from two sources produce graded potentials on the same neuron at the same time such that the two potentials sum.
Term
Which of the following changes in membrane potential is considered excitatory?

239)

_____

A)

depolarization only

B)

both hyperpolarization and depolarization

C)

repolarization only

D)

hyperpolarization only

E)

both hyperpolarization and repolarization
Definition
A)

depolarization only
Term
The spread of voltage by passive charge movement is called ________.

240)

_____

A)

diffusion

B)

integration

C)

propagation

D)

saltatory conduction

E)

electrotonic conduction
Definition
E)

electrotonic conduction


Term
If the graded potential remains above threshold once it reaches the ________, an action potential will be generated.

241)

_____

A)

cell body

B)

axon

C)

nucleus

D)

dendrite

E)

axon hillock
Definition
E)

axon hillock
Term
Which of the following characteristics does NOT describe an action potential?

242)

_____

A)

rapid increase in potassium permeability

B)

rapid increase in sodium permeability

C)

rapid reversal of membrane potential

D)

large depolarization

E)

it does not decay over long distances
Definition
A)

rapid increase in potassium permeability
Term
The opening of sodium channels causes a rapid ________ of sodium that ________ the neuron's membrane.

243)

_____

A)

influx : hyperpolarizes

B)

influx : repolarizes

C)

influx : depolarizes

D)

efflux : hyperpolarizes

E)

efflux : depolarizes
Definition
C)

influx : depolarizes
Term
The depolarization phase of the action potential is generated by a rapid ________.

244)

_____

A)

opening of potassium channels

B)

opening of sodium channels

C)

closure of potassium channels

D)

closure of sodium channels

E)

opening of chloride channels
Definition
B)

opening of sodium channels
Term
The repolarization phase of the action potential in a neuron is driven by the ________.

245)

_____

A)

closure of sodium channels and opening of potassium channels

B)

opening of calcium channels

C)

closure of potassium channels

D)

opening of sodium channels

E)

opening of sodium channels and closure of potassium channels
Definition
A)

closure of sodium channels and opening of potassium channels
Term
The patterns of change in ion channel permeability that occur during an action potential are due to ________ gating of voltage-sensitive potassium and sodium channels.

246)

_____

A)

mechanically-induced

B)

time-dependent

C)

temperature-induced

D)

light-sensitive

E)

ligand-driven
Definition
B)

time-dependent
Term
For the sodium channel to open and allow sodium into the cell, ________.

247)

_____

A)

only the inactivation gate must be open

B)

the activation and inactivation gates must both be open

C)

the inactivation gate must open shortly before the activation gate opens

D)

only the activation gate must be open

E)

the activation and inactivation gates must both be closed
Definition
B)

the activation and inactivation gates must both be open
Term
Which of the structures below lacks voltage-gated ion channels responsible for the production of action potentials?

248)

_____

A)

axon hillock

B)

muscle cell membrane

C)

nodes of Ranvier

D)

axon

E)

epithelial cell membrane
Definition
E)

epithelial cell membrane
Term
Which of the following events is fastest?

249)

_____

A)

opening sodium activation gates

B)

closing sodium activation gates

C)

closing voltage-gated potassium channels

D)

closing sodium inactivation gates

E)

opening voltage-gated potassium channels
Definition
A)

opening sodium activation gates
Term
Stimuli A and B are both suprathreshold stimuli that last for one second, but stimulus A is stronger. Which of the following statements is TRUE?

250)

_____

A)

The action potential produced by stimulus A will be larger than that produced by stimulus B.

B)

Stimulus A will cause a higher frequency of action potentials.

C)

Only stimulus A can produce an action potential.

D)

The action potential produced by stimulus A will be of longer duration than that produced by stimulus B.

E)

A single action potential will be produced by both stimulus A and stimulus B. The action potentials produced from each stimulus will be identical in size and duration
Definition
B)

Stimulus A will cause a higher frequency of action potentials.
Term
The repolarization phase of action potentials in neurons is due primarily to ________.

251)

_____

A)

sodium flow into the cell

B)

sodium flow out of the cell

C)

potassium flow out of the cell

D)

increased activity of the Na+/K+ pump

E)

potassium flow into the cell
Definition
C)

potassium flow out of the cell
Term
The regenerative nature of a sodium channel's activation gate refers to the situation where an activation gate's opening, and the resulting depolarization, ________.

253)

_____

A)

stimulates the opening of a potassium channel

B)

stimulates the inactivation gate of the same sodium channel to open

C)

stimulates the opening of another sodium channel's activation gate

D)

stimulates the opening of another sodium channel's inactivation gate

E)

stimulates the closure of other sodium channels' activation gates


Definition
C)

stimulates the opening of another sodium channel's activation gate
Term
The stimulation of an inadequate number of sodium channels for the generation of a positive sodium channel feedback loop is considered a ________ stimulus.

254)

_____

A)

threshold

B)

regenerative

C)

suprathreshold

D)

subthreshold

E)

degenerative
Definition
D)

subthreshold
Term
In order to generate an action potential, the magnitude of the inward sodium current must be large enough to overcome the ________.

255)

_____

A)

outward potassium current

B)

inward chloride current

C)

inward potassium current

D)

outward sodium current

E)

outward calcium current
Definition
A)

outward potassium current
Term
The positive feedback loop that is involved in the generation of an action potential is terminated by the ________.

256)

_____

A)

closure of activation gates on sodium channels

B)

closure of inactivation gates on sodium channels

C)

opening of inactivation gates on sodium channels

D)

closure of potassium channels

E)

opening of activation gates on sodium channels
Definition
B)

closure of inactivation gates on sodium channels
Term
The magnitude of an action potential will never reach sodium's equilibrium potential because ________.

257)

_____

A)

the inward movement of sodium is countered by the outward movement of potassium

B)

the sodium channel only opens for a short time

C)

the outward movement of sodium is countered by the inward movement of potassium

D)

the potassium channel opens slowly

E)

the inactivation gate closes the sodium channel so rapidly
Definition
A)

the inward movement of sodium is countered by the outward movement of potassium
Term
The all-or-none principle, associated with the action potential, states that ________.

258)

_____

A)

the positive feedback loop for the sodium channel is terminated by the inactivation gate

B)

all of the action potentials will be generated from the axon hillock

C)

following an action potential, the membrane will be repolarized by the opening of a potassium channel

D)

there is a positive feedback loop for sodium channels that results in a rapid membrane depolarization

E)

once membrane potential reaches threshold, an action potential will be generated and that action potential will always look the same
Definition
E)

once membrane potential reaches threshold, an action potential will be generated and that action potential will always look the same


Term
In order for a neuron to move from the absolute to the relative refractory period, a majority of that neuron's sodium channels must have their ________.

259)

_____

A)

inactivation gates closed and activation gates closed

B)

activation gates closed

C)

inactivation gates closed

D)

activation gates opened and inactivation gates closed

E)

inactivation gates open
Definition
E)

inactivation gates open


Term
Toward the end of the relative refractory period, the continued decrease in stimulus intensity required to initiate an action potential is caused by ________.

260)

_____

A)

the number of sodium channels whose inactivation gate has not opened

B)

decreased potassium permeability

C)

decreased sodium permeability

D)

closure of the sodium activation gate

E)

increased potassium permeability
Definition
B)

decreased potassium permeability
Term
The stimulus intensity required to initiate an action potential is ________ through the course of the relative refractory period.

261)

_____

A)

progressively reduced

B)

unaltered

C)

progressively increased

D)

increased

E)

stable
Definition
A)

progressively reduced
Term
Which of the following characteristics of an action potential does NOT result directly from the refractory period?

262)

_____

A)

the peak level of depolarization reached

B)

the all-or-none principle of action potentials

C)

the frequency of action potentials

D)

the unidirectional propagation of action potentials

E)

the lack of summation of action potentials
Definition
A)

the peak level of depolarization reached
Term
The time between action potentials is directly determined by the ________ the graded potential at the axon hillock.

263)

_____

A)

frequency of

B)

duration of

C)

distance traveled by

D)

amplitude of

E)

source of
Definition
D)

amplitude of
Term
For an unmyelinated axon, conduction velocity is primarily determined by the ________.

264)

_____

A)

diameter of the axon

B)

permeability of the axonal membrane

C)

number of ion channels present on the membrane

D)

type of potassium channel activated

E)

type of sodium channel activated
Definition
A)

diameter of the axon
Term
As an action potential is propagated away from the axon hillock, propagation continues in one direction only because ________.

265)

_____

A)

they will travel the path of least resistance

B)

the region just behind the action potential is in the absolute refractory period

C)

the region just in front of the action potential is in the relative refractory period

D)

the region just in front of the action potential is in the absolute refractory period

E)

the region just behind the action potential is in the relative refractory period
Definition
B)

the region just behind the action potential is in the absolute refractory period
Term
In myelinated nerve fibers, action potentials are produced at the ________.

266)

_____

A)

Schwann cell

B)

nodes of Ranvier

C)

underlying myelin sheath

D)

oligodendrocyte

E)

cell body
Definition
B)

nodes of Ranvier
Term
The jumping of an action potential from node-to-node is called ________.

267)

_____

A)

saltatory conduction

B)

electrotonic conduction

C)

nodal propagation

D)

propagation

E)

nodal conduction
Definition
A)

saltatory conduction
Term
Which of the following axons would have the fastest conduction velocity?

268)

_____

A)

diameter = 5 microns, unmyelinated

B)

diameter = 20 microns, myelinated

C)

diameter = 5 microns, myelinated

D)

diameter = 20 microns, unmyelinated

E)

diameter = 1 micron, myelinated
Definition
B)

diameter = 20 microns, myelinated
Term
Why do the distributions of sodium and potassium ions across the plasma membrane of neurons not change appreciably, even following hundreds of action potentials?

269)

_____

A)

The movement of sodium and potassium ions that occurs during an action potential is countered by the passive leak of these ions when a neuron is at rest.

B)

The movement of sodium and potassium ions that occurs during an action potential is countered by the passive movement of these ions during the after-hyperpolarization.

C)

The movement of sodium and potassium ions that occurs during an action potential is countered by counter-transport of potassium with sodium during rest.

D)

The movement of sodium and potassium ions that occurs during an action potential is countered by the active transport of these ions by the Na+/K+ pump.

E)

The movement of sodium and potassium ions that occurs during an action potential is countered by the passive movement of these ions during the repolarization phase
Definition
D)

The movement of sodium and potassium ions that occurs during an action potential is countered by the active transport of these ions by the Na+/K+ pump
Term
When solute is actively transported across epithelium, what usually follows?

270)

_____

A)

water movement in the same direction

B)

water movement in the opposite direction

C)

passive transport of solute in the same direction

D)

passive transport of the solute in the opposite direction

E)

active transport of the solute in the opposite direction
Definition
A)

water movement in the same direction
Term
The body is able to synthesize the amino acids glutamate, aspartate, and glycine from ________.

271)

_____

A)

essential amino acids

B)

the degradation of glucose in glycolysis and the Krebs cycle

C)

the glycerol in a triglyceride

D)

the degradation of fatty acids

E)

cholesterol
Definition
B)

the degradation of glucose in glycolysis and the Krebs cycle
Term
At the resting membrane potential, the membrane is most permeable to ________, which moves ________ the cell due to its electrochemical gradient.

272)

_____

A)

sodium : into

B)

sodium : out of

C)

potassium : out of

D)

potassium : into

E)

chloride : into
Definition
C)

potassium : out of