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PGY 206 Exxam 1
Study for PGY 206
75
Anatomy
Undergraduate 3
09/21/2015

Additional Anatomy Flashcards

 


 

Cards

Term

 

 

 

Define a negative feedback system.

Definition

 

 

Negative feedback - a change in a variable leads to a response that moves the variable opposite of the initial change

Term
Define and describe the four parts of a homeostatic control mechanism.
Definition

1. variable - the factor that is being regulated and is subject to change. Ex: body temperature.

 

2. sensor (receptor): detects changes in the variable from a set point.

 

3. integrating/control center - receives information from the sensors and determines a solution to the change

 

4. effectors - make the change given by the integrating center on the variable

Term
Diagram a homeostatic control mechanism.
Definition
[image]
Term
Define a positive feedback homeostatic control system.
Definition

A change in the variable leads to responses that movethe variable in the same direction of the initial change.

Term
What makes the structure of the plasma membrane unique?
Definition

The phospholipid bilayer embedded with hydrophilic proteis.

 

Phosphate group - polar - hydrophilic - water soluble

 

Fatty acid chains - nonpolar - hydrophobic - oil soluble

 

This structure prevents hydropilic molecules from crossing the membrane.

Term

What is an integral protein?

 

What is a peripheral protein?

Definition

An integral protein spans the entire width of the plasma membrane. (Ex: transporters, channels, receptors, carriers)

 

A peripheral protein is partially embedded on either side of the plasma membrane. (Ex: enzymes, structural support, receptors)

Term

What is a glycolipid?

 

What is a glycoprotein?

Definition

A glycolipid is a molecule which consists of both a carbohydrate and a lipid.

 

A glycoprotein is part carbohydrate, part protein.

Term
There are no ____ between the lipids and the proteins that make up the plasma membrane.
Definition
Bonds
Term

What are cilia?

 

What are flagella?

 

What are microvilli?

 

All of these structures seek to increase ____ __?

Definition

Cilia are short cell surface projections with motile properties. They are surrounded by the membrane and make the cells not perfectly spherical.

 

Flagella are long-whip like structures that do things like proper sperm. Covered by plasma membrane.

 

Microvilli - very small, finger-like extensions of the membrane.

 

Surface area.

Term

The plasma membrane is _______ permeable.

 

____ molecules diffuse through the membrane while ____ molecules diffuse through the pores.

 

Endocytosis is?

 

Exocytosis is?

Definition

Selectively. Things that influence permeabilty are size, charge, and polarity.

 

Lipohilic molecules diffuse through the membrane, hydrophilic through the pores.

 

Endocytosis brings molecules into the cell.

Phagocytosis is for large molecules, pino is for smaller.

 

Exocytosis brings molecules out of the cell.

 

Term

What is cytoplasm?

 

What is cytosol?

Definition

Cytoplasm is the region between the nucleus and the plasma membrane. Includes cytosol and organelles suspended in the cytosol. 

 

Cytosol is the fluid in which the organelles are suspended. Composed of water and other dissolved substances. Contains protein fibers like microfilaments and microtubules which function as a cytoskeleton.

Term
What are ribosomes?
Definition

Ribosomes are small granules composed of protein and RNA.

 

They are the site of RNA and protein synthesis. Proteins are assembled by a chain of amino acids.

Term

What is the endoplasmic reticulum?

 

What is rough ER?

 

What is smooth ER?

Definition

ER is a site of disctribution for various cellular molecules. It's usually connected to the golgi apparatus.

 

Rough ER has a lot of ribosomes on its surface. Rough ER packages proteins and distributes them to other organelles.

 

Smooth ER has no granules on the surface and is composed of tubules. It is the site of lipid and steroid synthesis, and is sometimes responsible for storing calcium.

Term

What is the golgi apparatus?

 

 

Definition
The golgi apparatus is a stack of smooth membrane sacks with associated vesicles. It modifies proteins received from the rough ER and packages them into vesicles.
Term
What is the mitochondria?
Definition
The mitochondria is a double-membraned structure responsible for synthesizing energy (adenosine triphosphate ATP). The double-membrane is in place in order to maximize surface area and therefore reaction sites.
Term

What are lysosomes?

 

What are peroxisomes?

Definition

Lysosomes are membrane bound sacs that contain digestive enzymes. Clean up wastes in the cell.

 

Peroxisomes are membrane bound sacs which contain enzymes to break down toxic substances in the cell. Clean up wastes.

Term

What is the nucleus?

 

How is it structured?

 

 

Definition

The nucleus is the hub of genetic matierial of the cell/body.

 

It is surrounded by the nuclear envelope (double membrane, two lipid bilayers)

 

The nuclear pores join these two membranes together.

 

Nucleoli are dense structures which contain genes for forming RNA associated with ribosomes.

 

Chromatin are threadlike material composed of histone proteins.

Term

What is the function of the nucleus?

 

How many chromosomes do humans have?

Definition

The nucleus is the control center of the cell; responsible for transmitting genetic information and providing instructions for protein synthesis.

 

Humans have 46 chromosomes, each composed of 1000s of genes.

Term

You can make DNA from DNA through the process of ______.

 

You can make messenger RNA (mRNA) from DNA through the process of ______.

 

You can make proteins from mRNA through the process of ______.

Definition

Replication.

 

Transcription.

 

Translation. (mRNA serves as a template; tRNA helps bring amino acids to ribosome)

Term
What are stem cells?
Definition

Cells that haven't differentiated to a specific role.

 

They can be collected as embryonic stem cells or as adult stem cells taken from the blood.

Term
About what percentage of body mass is water?

About what percent of body mass is extracellular water?

Intracellular?
Definition
60%

20%

40%
Term
What is interstitial fluid?

What does ICF stand for? ECF?

What is plasma and what does it do?
Definition
Interstitial fluid is the fluid "between cells" (80% of ECF volume)

intracellular fluid, extracellular fluid

Plasma is the noncellular portion of blood (20% of ECF)
Sweat glads take water from the plasma.
Plasma restores water from the interstitial fluid
Interstitial takes water from cells
This process is constantly trying to reach homeostasis.
Term
What is passive transport?

Active transport?
Definition
Passive transport does not need energy in the form of ATP to pass material through a membrane. It's dependent upon concentration/electrical voltage. Moves substances from higher to lower concentration, aka it moves down a concentration gradient.

Active transport requires energy in the form of ATP. Moves a substance from lower to higher concentration, aka moving against the concentration gradient.
Term
What is simple diffusion?

Simple diffusion is a ______ transport process.

When [molecules] is in equilibrium, net diffusion is ____.
Definition
Simple diffusion is the approach of molecules in a concentration gradient to reach homeostasis. Substances will move across a membrane to achieve uniform concentration.

Passive.

Zero.
Term
A higher concentration gradient (increases/decreases) rate of diffusion.

Increased temperature (increases/decreases) rate of diffusion.

Increased permeability?

Increased surface area?
Definition
All of these factors increase the rate of diffusion.
Term
What is facilitated diffusion?

Facilitated diffusion is a ____ transport process.
Definition
FD is a movement of large, polar substances across the plasma membrane via carrier (integral) proteins.

Passive.

Carrier proteins interact only with specific molecules, but they can bind to molecules of similar structure.

Two different molecules can compete for the same protein.

When all proteins are being utilized to move molecules, they are said to be saturated.
Term
What is osmosis?

Osmosis is a _____ transport process.
Definition
Osmosis is the diffusion of water across a membrane in order to facilitate homeostasis. In order for osmosis to occur, there must be a difference in the solute concentration across a membrane, and the membrane must be permeable to water, but not the solute.

Passive.
Term
What is osmotic pressure? (Pi)
Definition
Osmotic pressure is the pressure required to prevent osmosis.
Term
What is osmolarity?
Definition
Osmolarity is the number of particles in a solvent combined in one joint molarity.

The total osmolality of extra/intracellular fluid is 300mOsm.
Term
What is tonicity?

Isotonic? Hypertonic? Hypotonic?
Definition
Tonicity describes the number of particles inside and outside of a cell membrane.

An isotonic solution has a net diffusion of zero as both concentrations around a cell are the same. The cell stays the same size.

A hypertonic solution has a lower concentration inside the cell than out. Water diffuses outside of the cell and the cell shrivels.

A hypotonic solution has a higher concentration of particles inside the cell. Water diffuses in and the cell swells and can burst.
Term
What is primary active transport?
Definition
Primary Active Transport DIRECTLY utilizes the energy released by the hydrolysis of ATP.

The sodium-potassium pump is an example of this. A carrier protein enzymatically hydrolyzes ATP and pumps sodium and potassium in/out of the cell body.
Term
What is secondary active transport?
Definition
Secondary active transport INDIRECTLY uses the energy released by the hydrolysis of ATP.
Term
What is bulk tranport?

Bulk transport is a ____ transport process.
Definition
Bulk transport is the movement of large molecules across the plasma membrane. It requires energy to perform. Examples are exo/endocytosis.

Active.
Term

Fill in the hierarchy of the Central Nervous System and the Peripheral Nervous System.

 

Brain and Spinal Cord

 

 INPUT

            ______

                           _____ - visceral organs

                           _____ - sensory organs

 

OUPUT

        ______

                 Autonomic

                           _______ - cardiac

                          ________ - smooth glands

                  _______

                           skeletal muscle

 

 

Definition

Brain and Spinal Cord

 

 INPUT

            Afferent

                           Visceral - visceral organs

                           Sensory - sensory organs

 

OUPUT

        Efferent

                 Autonomic

                          sympathetic - cardiac

                          parasympathetic - smooth glands

                  Somatic

                           skeletal muscle

Term
Define afferent. Define efferent.
Definition

Afferent - bring information INTO the system. ex "afferent site."

Efferent - bring information OUT of the system.

Term
Detail the components of the Central Nervious System (CNS).
Definition

The CNS consists of the brain and the spinal cord.

 

Cerebrum - part of the brain in charge of conscious awareness

 

Cerebellum - integration of afferent and efferent signals "learned movements"

 

Brain stem - vegetative function, afferent and efferent run through the brain stem

Term
Detail the components of the Peripheral Nervous System (PNS)
Definition

These are primarily nerves that project to and from the CNS.

 

Spinal nerves and cranial nerves.

 

Afferent division - sensory - transmits impulses from the sensory receptors to the CND. Types of receptors: photoreceptors, chemical receptors, pressure/touch, etc

 

Efferent division - motor - transmits impulses from the CNS to the effector organs

 

somatic nervous systems - motor neurons that stimulate contraction of skeletal muscles

 

autonomic nervous system (ANS) - motor neurons that stimulate contraction of smooth and cardiac muscle and glandular tissue

Term
What are the main types of cells in the nervous system? Define them.
Definition

Neurons - specifically designed cell that transmit information using electrical impulses

 

glia - "supporting cells" protecting cells

Term
What is an action potential?
Definition
An action potential is an electrical signal carried by neurons.
Term

Define the following phases of the Action Potential.

 

1 ) Resting state

 

2) slow rising state

 

3) rapid rising state

 

4) repolarization

 

5) hyperpolarization

Definition

1) ions moving through the passive channels to maintain resting potential

Na+/K+ ATPase maintains concentrations

 

2) stimulus depolarizes the membrane by acting on chemically-gated channels (or mechanically, temperature, etc) resulting in Na+ moving into the neuron. If the threshold value is reached, an action potential will be initiated.

 

3) Once threshold is reached, many more voltage-gated Na+ channels open. This process continues until action potential peaks via positive feedback.

 

4) voltage gated Na+ channels close via inactivation. Na+ begins to diffuse away from membrane and are pumped out of neuron. Voltage-gated K+ channels open and as K+ leads, the neuron is repolarized.

 

5) voltage-gated K+ channels remain open for a brief period of time after the neuron reaches its resting potential

Term

Action Potentials are ___ or ___, meaning it can occur maximally or not at all. 

 

If a stimulus is strong enough to depolarize the membrane to _____, then an AP will be generated, and each one will always be the same ____.

 

Stimulus strength is indicated by the ______ of APs. With a ____ stimulus, there will be an increase in the frequency of APs.

Definition

All or nothing.

 

Threshold. Amplitude.

 

Frequency. Greater/Larger.

Term

What is a refractory period?

 

What is an absolute refractory period?

 

What is a relative refractory period?

Definition

A refractory period sets an upper limit for maximum frequency.

 

An ARP is the period of time during an AP when the membrane will not respond to a second stimulus - inactivation of Na+ channels

Another AP cannot be generated until the preceding one is finished.

 

A RRP is the period of time during an AP when a second AP can be produced, but only which a must stronger stimulus.

Term
Detail the propagation (or conduction) of the Action Potential.
Definition

1. stimulus depolarizes membrane to produce AP

2. positive charges are conducted to an adjacent region of the membrane

3. adjacent membrane regions are depolarized to produce another AP; however, the membrane area that just produced an AP is now refractory and cannot produce another AP

Term

Define the structural units of the neuron.

 

1. cell body (soma) - 

2. dendrites - 

3. axon (hillock, terminal)

4. synapse

5. tract/nerve

Definition

1. cell body (soma) - enlarged portion of the neuron which contains the nucleus and other organelles

nuclei - a group of cell bodies within the CNS

ganglia - a group of cell bodies within the PNS

 

2. dendrites - branched processes that extend from the cell body, afferent

 

3. axon - a single process that extends from the cell body, efferent

axon hillock - site where an AP is most likely to occur, occurs right after the cell body on the neuron

axon terminals - end of the axon

4. synapse - the gap between neurons

5. tract - a group of axons in the CNS

nerve - a group of axons in the PNS

Term

Describe the following classifications of neurons:

 

Pseudounipolar 

Bipolar

Multipolar

Definition

Pseudounipolar - usually sensory nerves, found in a ganglia

cell body hangs off an axon with two dendritic branches 

 

Bipolar - rare, found in the eye

cell body is found between two axons/ two dendritic brances

 

Multipolar - most neurons

cell body is directly connected to dendrites and axon

Term

sensory/afferent neurons carry information from the sensory receptors to the ____

 

motor/efferent neurons carry info from the CNS to the ___ _____

 

interneurons are found within the CNS and connect the ____ and ____ neurons

Definition

to the CNE

 

to the effector organs

 

afferent and efferent neurons

Term

What are Schwann cells and what do they do?

 

What are nodes of Ranvier and what occurs at them?

 

What are satellite cells?

 

These are all supporting cells within the _____ nervous sytem.

Definition

Schwann cells wrap around the axons to form the MYELIN SHEATH, they protect the axons

 

Nodes of Ranvier are the spaces between the Schwann cells; where action potentials are conducted 

 

Satellite cells surround the neuron cell bodies within ganglia in the PNS

 

Peripheral nervous system.

Term

Supporting cells of the CNS are called ____

 

What are oligodendrocytes and what do they do?

 

What are microglia and what do they do?

 

Astrocytes?

 

Ependymal cells?

Definition

They are called glia.

 

oligodendrocytes are similar to Scwann cells but they form a myelin sheath around axons of the CNS

 

microglia - phagocytes that help to get rid of foreign substances in the CNS

 

astrocytes help to maintain a normal external environment around neurons; maintain the blood brain barrier

 

ependymal cells - line the cavities of the brain and spinal cord, make cerebrospinal fluid (CSF)

Term

At rest, a neuron has an excess of positive charges on the ______ of the membrane and an excess of negative charges on the _____.

 

A negative resting membrane potential indicates that the inside of the cell is more ___ than the outside.

 

The concentration of (Na+/K+) is greater inside the cell, while the concentration of (Na+/K+) is greater outside the cell.

Definition

Outside, inside

 

negative

 

Potassium, Sodium

Term
The charges in the ECF are balanced by ____ while in the ICF large, negatively charged _____ balance the charge.
Definition
ECF is balanced by Chloride ions while ICF is balanced by large, negatively charged proteins
Term

At RMP, ___ is 75x more permeable than ___

 

Potassium moves ___ to ___ the cell

 

When this happens, the interior is left with a ____ charge

Definition

Potassium, sodium 

 

inside, outside

 

negative

Term

The sodium/potassium pump's official name is ______.

 

It pumps _ Na+ out for every _ K+ in.

 

The pump maintains the _____ _____ for these ions.

Definition

Sodium/Potassium ATPase

 

3, 2

 

concentration gradients

Term

Define depolarization.

 

Define hyperpolarization.

 

Define repolarization.

 

Resting membrane potential for a sensory neuron is ___ mV.

Definition

Depolarization is when the membrane potential becomes less negative/more positive.

 

Hyperpolarization is when the membrane potential becomes more negative/less positive.

 

Repolarization is a return to RMP.

 

RMP = -70mV

 

 

Term

If K+ permeability is increased, the membrane is _____.

 

If Na+ permeability is increased, the membrane is ____.

 

If intracellular K+ is decreased, the membrane is ___.

Definition

The membrane is hyperpolarized.

 

The membrane is depolarized.

 

The membrane is depolarized.

Term

Types of Integral Proteins

 

Define passive integral proteins.

 

Define chemically-gated channels.

 

Define voltage-gated channels.

Definition

Ion channels that are always open and allow ions to move down a concentration gradient.

 

Open when a substrate binds to a receptor on the channel and allows ions to move down their concentration gradients.

 

Open or close when they detect a change in membrane potential.

Term

Conduction velocity is proportional to the ____ of the axon.

 

Conduction velocity increases in a _____ axon.

 

APs occur at the ____, the spaces between the myelinated regions of the axon.

 

Define saltatory conduction.

Definition

Diameter.

 

myelinated axon

 

Nodes of Ranvier

 

saltatory conduction - conduction of an AP from one Node of Ranvier to the next

Term

What is a synapse?

 

In an electrical synapse the ____ signal is directly trasmitted between one cell to another.

 

Adjacent cells are joined together by ____ ______ (_____) that permit direct passage from one cell to the next.

 

Gap junctions conduct signals _________.

 

Electrical synapses found primarily in ____ and ____ muscle. 

Definition

A synapse is a functional connection between a neuron and a second cell. 

 

Electrical. 

 

gap junctions (connexins)

 

Gap junctions direct signals bidirectionally.

 

Electrical synapses found primary in smooth and cardiac muscle. 

Term
What are chemical synapses?
Definition

A chemical synapse is where an electrical signal is changed into a chemical signal (a neurotransmitter) which diffuses across the extracellular space between two cells. 

 

Transmission is unidirectional across a synapse - goes from the presynaptic to the postsynaptic cell.

 

There are special receptors on the postsynaptic membrane and special mechanisms to change the chemical signal back into an electrical signal. 

Term

In chemical transmission of electrical signals:

 

1. Action potential reaches the presynaptic terminals.

 

2. Depolarization activates voltage gated _____ channels resulting in an influx of _____ into the presynaptic terminal. 

 

3. Calcium triggers the fusion of the synaptic _____ (which can contain 10,000 molecules of neurotransmitter) wih the axon membrane leading of the release of neurotransmtters into the synaptic ____ via exocytosis.

 

 

Definition

2. calcium, calcium 

 

3. synaptic vesicles, synaptic cleft

Term

What is a synaptic cleft?

 

How do substances cross the cleft?

Definition

A synaptic cleft is the space between the presynaptic cell and the postsynaptic membrane, about 30-50 nm. Even though this gap is small, this can take a millisecond to happen.

 

Substances cross the cleft because of diffusion.

Term

Postsynaptic mechanisms for chemical transmission -

 

1. neurotransmitters move across the synaptic cleft and bind to ____ on the postsynaptic membrane.

 

2. chemically gated _____ or ____ channels open, allowing ions to flow through which generates electrical signal

 

3. _____ ______ ____ (EPSPs) - small polarizations of the membrane usually due to the influx of sodium

 

A single EPSP changes the membrane potential only a few millivolts which can't produce an AP; however, EPSPs can summate to threshold. 

Definition

1. receptors

 

2. sodium, potassium

 

3. Excitatory PostSynaptic Potentials

Term
The AP originates at the axon ____ as it contains the greatest concentration of voltage gated ___ channels.
Definition
hillock, sodium
Term
____ ____ _____ (IPSPs) - small hyperpolarizations of th membrane due to the outflow of ____ and/or the inflow of ____ through chemically gated channels.
Definition
Inhibitory PostSynaptic Potentials, potassium, chloride
Term

Termination of Synaptic Transmission (How the body gets rid of neurotransmitters from the receptor)

 

1. neurotransmitters dissociates from the receptor and _____ away from cleft

 

2. neurotransmitters are taken back into the presynaptic terminals via _____

 

3. degrading _____ break down neurotransmitters

Definition

1. diffuses away

 

2. reuptake

 

3. enzymes

Term

Acetylcholine (Ach) as a neurotransmitter

 

1. first _____ identified 

 

2. stored in ____; released from _____ terminals into the synaptic cleft

 

3. binds to specific receptors on the postsynaptic cell which are

a. ______ - binds with Ach and nicotine

b. ______ binds with ach and muscarin

 

4. is degraded by an enzyme called _______ (AChE)

Definition

1. first neurotransmitter identified

 

2. stored in vesicles; released from presynaptic terminals

 

3. Nicotinic, muscarinic

 

4. acetylcholinesterase 

Term

What is a nerve?

 

What is a ganglia?

Definition

A nerve is a group of axons in the peripheral nervous system.

 

A ganglia is a group of neuron cell bodies in the peripheral nerous system.

Term

What is the autonomic nervous system?

 

Sympathetic - "____ or ____"

 

parasympathetic - "____ and _____"

 

 

Definition

The system responsible for involuntary activity.

 

Fight or flight.

 

Rest and digest.

Term

Arrangement of the Autonomic Nervous Stem (ANS)

 

Consists of 2 neurons that connect the CNS to the effector cells.

 

preganglionic fiber - this neuron has it cell body in the ____ and synapses with the second neuron at an autonomic ganglion outside of the ____

 

postganglionic fiber - this second neuron extends from the autonomic ganglion to the ____ cells

Definition

CNS, CNS

 

effector

Term

Neurotransmitters associated with SNS and PNS

 

1. all preganglionic neurons release _____

these are called ____ fibers

 

2. postganglionic neurons:

PNS - release ___

SNS - primarily release _____

called ______ or _____ fibers

Definition

1. all preganglionic neurons release acetylcholine

these are called cholinergic fibers

 

2. PNS - releases ACh

SNS - primarily releases norepinephrine (NE)

called adrenergic or catecholaminergic

Term

Receptors

 

1. cholinergic recepters (activated by ___)

a. nicotinic receptors (N) located on ____ and ____ postganglionic neurons

b. muscarinic receptors (M) found on effector cells stimulated by parasympathetic postganglionic neurons

 

2. adrenergic receptors (activated by ____ and ____)

a. found on effector cells stimulated by ____ postganglionic neruons

b. ____ receptors (a1 and a2)

____ receptors (b2 and b2)

Definition

1. cholinergic receptors (activated by ACh)

a. located on sympathetic and parasympathetic postganglionic neurons

 

2. adrenergic receptors (activated by norepinephrine and epinephrine)

a. simulated by sympathetic postganglionic neurons

b. alpha

beta

Term

Autonomic Regulation of Specific Organs 

 

PNS - "rest and digest"

associated with conservation of energy and maintenance of organ function durning times of minimal activity

 

SNS - "fight or flight"

prepares the body for responding to fear, stress, etc

Definition
Yeah
Term

Autonomic Regulation of Specific Organs

 

1. Heart

PNS - ___ from the postganglionic neuron binds to ____ receptor

*decreases heart ___

*decreases force of ____

 

SNS - ____ binds to ____ receptors

*increases heart ___

*increases force of ____

Definition

1. Heart

PNS - ACh from the postganglionic neuron binds to muscarinic receptor

*decreases heart rate

*decreases force of contraction

 

SNS - norepinephrine binds to beta-2 receptors

*increases heart rate

*increases force of contraction

Term

Autonomic Regulation of Specific Organs


Lungs

a. PNS - ____ on and ____ receptor

*contracts bronchial muscle - _____ the airways


b. SNS - _____ on a ____ receptor

*relaxes _____ muscle


GI Tract

a. PNS

*Increases motility

*increases secretions

b. SNS

*decreases motility

*decreases secretion but may increase ____

Definition

Lungs

a. PNS - ACh on and muscarinic receptor

*contracts bronchial muscle - constricts the airways


b. SNS - Norepinephrine on a beta-1 receptor

*relaxes bronchial muscle


GI Tract

a. PNS

*Increases motility

*increases secretions

b. SNS

*decreases motility

*decreases secretion but may increase mucus

Term

Autonomic Regulation of Specific Organs


4.  Blood Vessels

a. PNS

·         no direct innervation of vascular (around arteries and veins) smooth muscle

 

b.     SNS alpha receptor

·         constriction of most blood vessels

·         dilation of blood vessels that supply the skeletal muscles

 

 

Eye

a.       SNS – dilate pupil

b.      PNS muscarinic – constrict pupil

 

Normal control is mostly PNS – so blocking causes…

Definition

4.  Blood Vessels

a. PNS

·         no direct innervation of vascular (around arteries and veins) smooth muscle

 

b.     SNS alpha receptor

·         constriction of most blood vessels

·         dilation of blood vessels that supply the skeletal muscles

 

 

Eye

a.       SNS – dilate pupil

b.      PNS muscarinic – constrict pupil

 

Normal control is mostly PNS – so blocking causes…

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