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Physiology
Exam 2: Study Guide
88
Physiology
Undergraduate 3
03/21/2010

Additional Physiology Flashcards

 


 

Cards

Term

What are the four main components of the brain stem?

 

What do they each consist of/do?

Definition

1.diencephalon: hypothalamus, thalamus (vision), epithalamus(hormones)

 

2. Mesencephalon: routes sensory info to the brain and sends out motor info

 

3. pons: ponteine centers deal with cardiovascular and respiratory nerves

 

4. medulla oblongata: continuous/ connector to the spinal

Term
Where is the cerebellum and what is it's function?
Definition
It's at the base of the cerebrum and it is used to help create smooth fluid movement.
Term
what is the function of the cerebrum? what is another name for cerebrum?
Definition
the cerebrum (or cortex) is associated with higher level function such as thought and action. Other examples of higher level functions: reasoning, logic, speech, memory etc etc
Term
what are neuroglial cells and how do they function differently than neurons?
Definition
neuroglial cells support nuerons. They aren't usually able to have action potentials but rather they help the neurons to have their action potentials.
Term
what are the main types of neuroglial cells and what do they do?
Definition

1. microglial cells: type of white blood cells that eliminate pathogens

 

2. oligodendrocytes: mylenate neurons in CNS

 

3. Schwann cells/neurolemmocyte: myelinate neurons in PNS

 

4. astrocyte: transports glucose across the blood brain barrier and into the brain

Term
what is the difference between neurolemmocytes and oligodendrocytes?
Definition
they both myelinate axons but neurolemmocytes do it in the peripheral nervous system while oligodendrocytes do it the central nervous system.
Term
what is a membrane potential? what does it represent?
Definition

a RMP is a baseline charge difference between intracellular and extracellular compartments

 

it represents potential energy and energy that is stored with the potential to do work

Term
what is the RMP range for regular cells vs neurons in mammals?
Definition

regular cells: -40--> -90 mV

neurons: about -70mV but between -60 and -90 mV

Term
For any neuron, how do Na+ and K+ differ in their concentrations? Which one has the greatest difference in it's concentration inside and out of the cell?
Definition

high Na+ concentration outside of the cell

high K+ concentration inside the cell

 

K+ has higher differnce between it's concentration inside the cell and its concentration outside of the cell

Term
In a neuron, in what direction are Na+ and K+ moving down their gradeints?
Definition

Na+ wants in

 

K+ wants out

Term
In a neuron, as a result of the Na+ and K+ concentrations, what is the charge gradient?
Definition
In side negative outside posi
Term

When dealing with values of "driving force" what does the positive or negative sign indicate?

 

In a neuron, how do the driving forces of Na+ and K+ differ? What does this mean?

Definition

A positive driving force means that the ion wants to move INTO the cell. A negative diving force means it wants to move OUT of a cell.

 

K+ has a driving force of -20mV while Na+ has a driving force of 130mV. This means that Na+ wants in more than K+ wants out.

Term
In a neuron, which is more membrane permeable: K+ or Na+?
Definition
K+
Term
what are the three main factors that cause the inside negative and outside positive of a neuron?
Definition

1. K+ wants to move out of the cell, but because it is a + ion it attracts negative ions. So, as K+ moves towards the plamsa membrane, it brings along negative molecules that end up getting stuch on the inside of the plasma membrane when the K+ moves out.

2. Na/K pump, pumps out 3 Na+ and only lets in 2 K+ creating a charge difference across the membrane

3. K+ can easily leak out of channels which, as stated above creates a negative charge on the inside of the plasma membrane. As a result of that negative charge, Na+ is attracted to the outside of the plasma membrane.

Term
what factor contributes the most to the RMP?
Definition
the diffusion of K+ out of a cell and the combination of that and the negative molecules that it drags to the inner surface of the plasma membrane
Term
Why does K+ exert a greater impact on RMP than Na+?
Definition
because the membrane is more permeable to K+ and the Na+/K+ leak channels conduct way more K+ than Na+
Term
Why doesn't K+ ever reach electrochemical equilibrium?
Definition
Because K+ is ALWAYS leaking out of those leak channels
Term
Define the following: Resting membrane potential, diffusion potential, action potential and electrochemical equilibrium potential.
Definition

RMP: baseline charge difference between intra and inter cellular compartments

 

Diffusion Potential: the electrogenic diffusion potential that accounts for most of the RMP

 

Action Potential: series of diffusions of Na+ and K+ down the axon of a neuron

 

Electrochemical equilibrium potential: Electrochemical equilibrium is the theoretical voltage that would be attained when an ion is at equilibrium inside and outside of the cell. The electrochem equil. potential is the difference between the equilibrium state and the current state of an ion. An ion that is far from being at equilibrium will have a higher electrochemical equilibrium potential.

Term
What is the Nerst equation and what is it used for?
Definition

It is used to estimate the equilibrium potential

 

Equil. Pot.=-60log(ion conc inside/ion conc ouside)

Term
what are the two reasons that account for the importance of K+ when it comes to RMP?
Definition

1. K+ is super permeable

2. There is a great

Term

why is the magnitude of any successful action potential a constant number?

 

what is that number?

Definition

APs are all or nothing things. They are nondecremental meaning that they do not degrade as they move down an axon. Once there is a large enough charge difference created for an action potential, it will go all the way.

 

40mV

Term
What does and Na+ voltage gated channel look like?
Definition
[image]
Term
What are the active, inactive and resting states of the Na+ voltage gated channels?
Definition

Na+ voltage gated channels have both inactivation and active gates...So:

1. When the channel going through the gate is closed and the hole on the inside is still open the channel is resting

2. when the channel going through the gate is open and the hole on the inside is open as well, then the channel is activated

3. When the channel is open and the hole is plugged by the inactivation gate, then the channel is inactivated

 

 

Term
What are the different states of K+ voltage gated channels?
Definition
Unlike Na+ voltage gated channels, K+ channels don't have an inactivation gate. So, they are either resting or activated based on whether or not the channel running through it is open or closed.
Term
Because Na+ and K+ have charges they typically float around in solution with a hydration shell around them. What allows them to be trasported through their voltage gated channels without taking the hydration shell with them?
Definition
The insides of the voltage gated channels are lined with Oxygen which takes the Na+ but doesn't have a high affinity for water so the hydration shell gets left behind.
Term

Ultimately what is the source of energy for an action potential?

 

During the action potential, what source of energy drives it onwards?

Definition

Ultimately the energy comes from the RMP

 

During the AP, it is driven forwards the changes in ion concentrations due to the opening and closing of voltage gated channel.

Term
Draw and action potential graph and label the points where different gates open and close
Definition
[image]
Term
what are absolute and relative refractory periods?
Definition

absolute: the peak of an AP where an AP cannot be initiated because all the local Na+ VG channels are already open, so you can't open more. Basically an AP can not happen when one is already in progress.

 

relative: this is during the undershoot/hyperpolarization phase. APs can be started but the threshold is high because some of the K+ channels are still acitvated and some of the Na+ channels are still inactivated.

Term

in an action potential diagram where are the following:

 

slow rising phase

depolarization phase

repolarization phase

hyperpolarization

Definition

slow rising phase is the little hump before the large spike

 

depolarization is the rapid rising phase

 

repolarization is the rapid decrease

 

hyperpolarization is the undershoot

Term

what is a graded potential?

 

what type of conduction is this?

Definition

it is a failed attempt at an action potential.

 

when this happens there is a small influx of Na+ but not enough to create and AP so the little graded potential moves along the axon but while it does so it gets smaller and smaller and eventually fades out.

 

decremental conduction

Term
what are STPs?
Definition

sub threshold potentials

 

little influxes of Na+ that are not enough to create and action potential. they are usually graded potentials that are decremental.

Term
Give two reasons why propagation occurs in the anterograde direction as opposed to the retrograde direction
Definition

1. inactivation of the Na+ VG channels prevents reverse propagation

 

2. The inside negative charges on the anterograde side of the AP pull the positive charge on the retrograde side forward

Term
diagram of the propagation of the action potential
Definition
[image]
Term

 

What are two mechanisms by which the membrane in the anterograde direction of the action potential becomes less inside-negative prior to the initiation of an action potential at that location.

 

What process pushes the membrane at that location to become more inside-negative?

 

 

Definition

1. At the place of the AP there is a positive inside charge so that charge tends to move towards the anterograde side reducing the negativity of the anterograde side.

 

2. Also, on the outside there is a positive charge that is being drawn away towards the outside negative at the AP point. This causes the inside negative at the anterograde to want out as well.

 

Also anterograde positive is always leaking through the channels which actually increases inside negative.

Term

 

 

 

What is the significance of the spacing of neurofibril nodes on an axon?

Definition
They are almost exactly 1mm apart which is significant because that is about how far away one AP can initiate the next
Term
What are two reasons why myelin increases the rate of conduction of an AP?
Definition

1. Causes a saltatory conduction which is much quicker than carrying charge in and out at every point along the axon

 

2. It also prevents positive charge leakage that results from the increase in inside posi charges that repel eachother

Term
what does action potential propagaion velocity depend on?
Definition
fiber diameter and myelination
Term
what are spatial and temporal summation
Definition

spatial summation is when two influxes of a positive stimulus from different places on the soma add up

 

temporal summation is when several positive stimuli from the same presynaptic terminal add up

Term

Explain how temporal and spatial summations of neurotransmitter activity cause the initiation of an action potential at the axon hillock.  In your explanation, include the terms EPSP and graded potential.

 

 

Definition
Summations allow for enough of a positive neurotransmitter stimuli to initiate and action potential. The + NTs move from the soma to the axon hillock where the positive charge causes the Na+ gates to open. If there is enough +NTs from the summations then there will be an Excitatory Postsynaptic Potential (EPSP) which allows for an AP to occur and travel down the axon. If there is not enough +NTs from the summations, then there will be a graded potential which causes just a little big of the Na+ gates to open. This little graded potential flows down the axon, but because it's so small it fades out on the way (decremental conduction).
Term
IPSP vs EPSP
Definition

IPSP: Inhibitory Postsynaptic Potentials are an influx of negative charge that cause hyperpolarizations that inhibit APs

 

EPSP: Excitatory Postsynaptic Potentials are influxes of positive charge that can initiate an AP at the axon hillock

Term
Gray and White Matter, Brain and Spinal cord
Definition

Brain: gray outside 6 layers of soma, white inside

 

Spinal cord: white outside grey inside

Term
Dorsal and Ventral Roots
Definition

Dorsal roots: afferent pathway, sensory

Ventral Roots: efferent pathway, motor

Term
What do grey and white matter consist of?
Definition

grey= soma

white= dendrites and axons

Term
Which roots have ganglia?
Definition
dorsal roots
Term
What is a connexon and why do I care?
Definition
A connexon is a positive gradient that a message flows down from neuron to neuron. These are common in electrical synapses that involve ion passage through gap junctions in the brain.
Term
events during high molecular weight neurotransmitter secretion:
Definition

1- NT made in the somae

2- anterograde NT vesicle transport

3- docking

4- action potential propagation allows for

5- activation of CA + (Ca+ influx)

6- quantum is released

7- binds to post synaptic cell receptors

Term
Acetylcholine
Definition

low molecular weight, Amine

uses cholinergic receptors: nicotinic (ligand gated) and muscarinic (g-protein)

synthesized in axon terminals

CNS and PNS

secreted by cholinergic fibers, requires acetytransferase

Acetyl CoA derivative

 

 

Term

ADH

 

Definition

high molecular weight neuropeptide

made in soma

modulates low molecular weight activity

peptide

 G protein linked metabotropic

made in hepatocytes

Term
Aspartate
Definition

amino acid/ monoamine

ligand gated (ionotropic)

CNS

low molec. wght synthesized in axon terminal

 

Term
Beta endorphin
Definition

uses adrenergic receptors

high molecular weight synthesized in soma

inhibitory NT of the CNS
Endogenous opioid; pain supression, analgesic

OPIUM HEROIN & LSD

Term
Dopamine
Definition

catecholamine (tyrosine derivative)

secreted by cerebral dopaminanergic fibers

mediates emotions

lack of= parkinsons, schizophrenia

CNS

Low molecular weight synthesized in axon terminals

metabotropic

 

 

Term
serotonin
Definition

monoamine

tryptophan derivative

low molecular wght synthesized in axon terminal

ionotropic ligand gated (some versions metabotrophic)

CNS

secreted in the brain stem

Term
Enkephalin
Definition

Endogenous opioid

inhibitory of the CNS

analgesic

Agonists: lsd opium morphine heroin

high molecular wght sythesized in the soma

Term

Gamma Amino Butyric Acid

GABA

Definition

amino acid

inhibitory CNS

ligand gated ionotropic

low molecular weight made in axon terminals

 

 

Term
Glucagon
Definition

peptide

hi molecular wght (made in soma)

secreted from pancreas

Term
Glutamate
Definition

amino acid

ligand gated ionotropic

low molec wght sythesized in axon terminals

CNS

EPSP NT

Term
Glycine
Definition

Amino acid

ligand gated

low molecular weight

inhibitory CNS

 

Term
insulin
Definition

high molecular weight

peptide

induces cell uptake of glucose

metabotropic

Term
peptides
Definition

are metabotropic!

ADH Glucagon insulin oxytocin and gastrin

Term
Norepinephrine
Definition

catecolamine (tyrosine derivative)

Secreted by adrenergic fibers in the CNS and PNS

secreted by chromaffin cells

metabotropic G protein linked

 

Term
What are the norepinephrine receptors?
Definition

Beta 1 - activate EPSPs to increase heart rate

Beta 2 - activate/ inactivate EPSP, decrease Heart activity (Beta blocker, grandpa's drug) smooth muscle relaxer

       - both Beta 1&2 activate adenylate cyclase

 

Alpha 1- increases intracellular CA++ smooth muscle contraction, uses phospholipase C

Alpha 2- inhibits adenylate cyclase (antagonistic to Beta receptors) uses the GI protein

Term
Oxytocin
Definition

peptide

hi molec wght

metabotropic

made in the soma

Term
 By what mechanism does a nicotinic receptor respond to ACh?
Definition

ligand gated channel

 

ACh from the ISS binds to the nicotinic receptors

this activates them allowing Na+ influx and K+ efflux

ACh can be reused later

 

Term

 Explain the difference between an m1 and an m2 receptor in terms of whether they are iontropic or metabotropic and whether they cause EPSPs or IPSPs

Definition

M1- muscarinic cholinergic receptor, receives acetylcholine, EPSP. Decreases K+ activity creating inside positive environment

 

M2- muscarinic cholinergic receptor, receives acetylcholine, IPSP. Increases K+ activity creating an inside negative environment

 

Both use G protein IP3 pathway

Term

Which of the following are agonists?

ACh

Mescaline

Beta-endorphine

Muscarine

Curare/tubocurarine

Nicotine

Enkephalin

Norepinerphrine

LSD

Opium

Definition

LSD

Opium

Mescaline

agonists of Beta endorphines and Enkephalin

 

ACH agonist of nicotine, muscarine

 

 

 

Term
curare
Definition
inhibits nicotinic receptors, causes paralysis
Term

ACh, acetylcholinesterase, choline, acetate, acetyltransferase, acetyl CoA, CoA

 

What is the relationship between them?

Definition

CoA makes AcetylCoA

AcetylCoA+ choline = ACh

Acetyltransferase transfers the acetyl group of AcetylCoA and puts it with Choline to make ACh.

Acetylcholinesterase breaks apart ACh after its hit post synaptic receptors. When broken apart, it is broken into choline and acetate. Choline gets recycled back into the pre synaptic terminal.

Acetylcholinesterase= AChe

 

See Slide 25 of slideset 4 for diagram

 

 

Term

I D NC

 

Smooth muscle contraction following increased adrenergic input to an alpha 1 receptor

Definition

Increase

 

The a1 receptors receive adrenergic responses that increase the intracellular CA++ which increases muscle contraction.

 

Adrenergic Responses: norepinephrine, catecholemines

Term

I D NC

 

intracellular IP# levels following decreased adrenergic input to smooth muscle alpha 1 receptors

Definition

Decrease

Adrenergic responses cause the Gprotein pathway that releases IP3, increases cellular CA++, causing muscle contraction

Term

Cytosolic adenylate cyclase activity following increased adrenergic input  to a2 receptors.

 

Definition

Decrease

 

increased adrenergic input to a2 receptors increases a2 receptor activity,

a2 receptors inhibit adenylate cyclase

 

Term
Force of heart contraction following decreased adrenergic input to b1 receptors.
Definition

Increase

b1 receptors cause heart to pump harder and faster once they receive adrenergic input

Term

cAMP concentration following increased adrenergic input to b1 receptors.

 

Definition

Increase

increase adrenergic input to B1 receptors increases their activity

B1 receptors activate adenylate cyclase

adenylate cyclase makes cAMP

Term

Arteriole constriction following decreased adrenergic input to b2 receptors of smooth muscle.

Definition

Increased

 

Decreased adrenergic input means decreased b2 activity

b2 relaxes heart

 

Term

 a1                        

 a2                    

b1

b2

What do they activate or inhibit?

Definition

a1      activates phospholipase C (PLC)                  

 a2     inhibits adenylate cyclase                

b1      activates adenylate cyclase

b2     activates adenylate cyclase

Term

Serotonin

 

Dopamine

 

How do funky levels affect mental health?

Definition

Serotonin- NT involved with pain perception. Overactive recovery from synaptic cleft leads to depression.

 

Dopamine mediates emotions and skeletal muscle movement- if the dopaminanergic fibers in ones brain degenerate = Parkingsons/ schizophrenia

Term

What are the two efferent pathway classifications?

explain their differences in terms of direct and indirect innervation and in terms of the effectors of each pathway.

Definition

somatic and visceral (autonomic)

 

Somatic= direct innervation, skeletal mm & skin

Visceral= indirect innervation, smooth mm & glands (heart and adipocytes)

 

 

Term
What are the divisions of the autonomic nervous system?
Definition

Sympathetic

Parasympathetic

Term

Dual innervation

Definition

Parasympathetic and sympathetic divisions both act on the effector

 

Smooth mm of blood vessels and sweat glands are only innervated by the Sympathetic nervous system

Term
What is the exception to the “indirect vs. direct innervation rule” within the ANS?
Definition

somatic cells- direct innervation

visceral- indirect innervation

 

BUT the exception is Chromaffin cells of the Visceral Nervous System have direct innervation

Term

Explain the differences between the parasympathetic and sympathetic autonomic nervous systems in terms of origins from the CNS

Definition

parasympathetic (craniosacral) comes out of the cranial and sacral vertebrae

 

sympathetic (thoracolumbar) comes out of the thoracic and lumbar vertebrae

Term

Explain the differences between the parasympathetic and sympathetic autonomic nervous systems in terms of autonomic ganglia location

Definition

parasympathetic ganglia follows a long preganglionic neuron

 

sympathetic ganglia follows a short preganglionic neuron

Term

Explain the differences between the parasympathetic and sympathetic autonomic nervous systems in terms of location of cholinergic and adrenergic fibers

Definition

Parasympathetic and Sympathetic nervous systems both have cholinergic fibers pre-ganglion

 

Parasympathetic NS also have cholinergiv fibers post ganglion

 

Sympathetic  NS has sdrenergic fibers post ganglion

Term

Which effectors are acted on by the Parasympathetic NS?

Definition

pupils constricted

stimulates digestion

slows heart beat

constricts airways of the lungs

vasodialation of blood vessels

clitoral and penile arousal

stimulates salivary glands

 

slide 4

 

 

Term
Which effectors are acted on by the Sympathetic nervous system?
Definition

dialates pupils

ihibits digestion

relaxed airways of the lungs

accelerates heartbeat

stimulates sweat glands

Constricts blood vessels

stimulates an orgasm

 

slide 10

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