• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/69

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

69 Cards in this Set

  • Front
  • Back

Somatic NS

there is onl one place where neurotransmitters are released since there is only one synapse! (Neuromuscular junction)



all somatic motor neurons release __________ at their synapse with skeletal muscles.


their effect is always __________

Acetycholine


excitatory (EPSPs)



Autonomic NS

since we have a two neuron system we have two synapses to deal with




preganglionic fiber>ganglion>postganglionic fiber> smooth or cardiac muscles, glands, or GI neurons



Autonomic NS: within the ganglion the signal needs to be ______________. this is similar to the somatic system and thus requires a neurotransmitters that is excitatory

transmitted from pre=ganglionic neuron to postganglionic neuron.

the neurotransmitter released in the synapse between pre- and postganglionic neurons is always

acetylcholine

the actual functional difference between parasympathetic and sympathetic nervous system is

thus at the level of the postsynaptic neuron and synapse with the effector organ

parasympathetic postganglionic neurons release

acetylcholine

sympathetic postganglionic neurons release

norepinephrine

sympathetic activation of the adrenal medulla is a special case because there is

no postganglionic neuron

the activated adrenal medulla releases:

epinephrine and norepinephine into the bloodstream



________________and __________________ are thus two major neurotransmitters released by the ANS

acetlycholine and norepinephrine

ACh is released by all preganglionic neurons of

PS and S and by all postganglionic PS neurons

Postganglionic Sympathetic neurons release



NE

neurons that release ACh are called:

cholinergic fibers

neurons that release NE are called

adrenergic fibers

ANS receptors:

the receptor, located in the cell membrane of the target cell, is a molecular transducer that sets in motion a series of cellular effects

the type of receptor determines

the specificity of cellular actions

the neurotransmitter is the molecular trigger. it requires

binding to the receptor before the receptor becomes activated

primary ligand+agonist=


antagonist=

response


no response

the two primary ligands, agonists of the ANS are thus

Acetylcholine and Norepinephrine (epinephrine)


acetlycholine binds to

cholinergic receptors

norepinephrine binds to

adrenergic receptors

cholinergic receptors

bind to ACh

two kinds of receptors:

1. nicotinic receptors also called nAChR


2. muscarinic receptors also called mAChR

cholinergic nicotinic receptors

members of superfamily of ligand gated membrane channels that mediate fast signal transmission at synapses

all nicotine AChRs are pharmacolically identical in that they bind _______ as a ligand agonist

nicotine

all nicotinic AChRs are _________

pentamers: they consist out of 5 polypeptide subunits that are clustered around a central receptor channel

there are 2 ligand binding sites formed by the aplha subunits and an adjacent subunit

binding to both sites needed for channel to open


binding to only one site prevents channel activation

binding of a ligand to the receptor causes conformational changes that ________

open the central channel to mostly Na and some K ions



what is the normal physiological ligand in the body

ACh

what occurs in the cell that has this receptor when bond binding sites are occupied with ACh

the channel that opens and Na rushes into the cell, resulting in depolarization

where do we find nicotinic cholinergic receptors

on post synaptic cell membranes that experience an exotysosis of ACh from presynaptic vesicles and requiring fast depolarization of the postsynaptic area

3 areas where find nicotinic cholinergic receptors

1. on the motor endplates of skeletal muscle (somatic nAChR)


2. on all cell bodies and dendrites of postganglionic neurons of parasympathetic and sympathetic system (ganglionic nAChR)


3. on the hormone producing cells of adrenal medulla

the effect of ACh on these receptors is thus always stimulatory. it causes a

depolarization of the cell (this is your typically chemically gated Na channel)

are the nACH receptors the same in the somatic system as the autonomic isystem

yes, they are similar in structure but have different proteins that make up the channel. different proteins react differently to different drugs/toxins.

Epibatidine

example of nAChR effector


isolated from the skin of an exuadorian frog


exhibits very potent agonistic properties


thus would induce ANS potetiation (hallucinations) and muscular spasms

curare

example of nAChR effector


isolated from the bark and leaves of the tropical plant Strychnos Toxifera


it is a potent nAChR blocker in the NMJ but affects ganglionic receptors as well


used to create muscle paralysis

where do we find muscarine cholinergic receptors

on teh target organs served by cholinergic postganglionic neurons (parasympathetic nerves)

cholinergic muscarinic receptors

these receptors bind ACh as well but the mechanism and response elicited by these receptors differs from previously discussed nAChRs

muscarine receptors bind ___________

muscarine



muscarine

a component derived from the fly agaric mushroom

muscarine receptors operate as ____________ and mediate their response by activating a variety of intra cellular pathways

G protein coupled receptors

there are two important G protein coupled systems determined by the specific enzyme that becomes activated and therefore different product produced.

this is a very common pathway and is similar in for example smell and taste activation

PLPc G protein coupled receptors

the concept of this pathway is the same except that a different enzyme is activated.

pLPc (phospholipase C) makes two products

Diacylglycerol (DAG) and Insoitol Triphosphate (IP3)

the purpose of these pathways is to generate

intracellular signals to activate specific tissues. those intracellular signals are the product of the activated enzymes (cAMP or DAG and IP3)

muscarinic receptors are typically found on

target tissues of the parasympathetic NS

if the receptors are located in smooth muscles:


if the receptors are located in glands:


if the receptors are located in impt metabolic cells

the purpose is to start or inhibit smooth muscle contraction


the purpose is to start or inhibit the secretion of the glands


the purpose is to start or inactivate metabolic processes

what effects do cAMP and DAG have

they both activate protein kinases


protein kinases in turn will phosphorylate and activate/inactivate proteins


this would be a fast way of turning on and off a metabolic pathway

IP3

acts on smooth ER


results is that calcium will be released into the cytoplasm


calcium in turn will bind to and activate a protein called calmodulin


activated calmodulin can now activate enzymes and other proteins

how many different kinds of muscarinic receptors are there

5

muscarinic receptors are named ______. these receptors are typical for parasympathetic target tissues

M1 to M5

M2

located in the heart


action: inhibits adenylate cyclase (thus decreases activities)

M3

located in gut smooth muscle, glands


action: activates PLP-C (mediates contraction)

the M2 receptor, when it binds to ACh (released from the vagus nerve)

will stop production of intracellular cAMP and ithis is the basis for reduced heart rate and heart contraction

The M3 receptor when it binds ACh will produce

IP3 and this is the basis for increases smooth muscle contraction. found in the constrictor muscles of the iris and smooth muscle of digestive system

muscarinic antagonists

prevents activation of parasympathetic target organs

atropine:

plant: atropa belladonna


lethal dose: 10 berries


dilated pupils, hallucinations, urinary retention

adrenergic receptors also called adrenoceptors

mediate the acitons of epinephrine, norepinephrine and related compounds



adrenergic receptors are found on the target organs of the

sympathetic nervous system

epinephrine and norephiinephrine belong to the class of

catecholamines and are the derivatives from the amino acid: tyrosine

these receptors (adrenergic) are also coupled to

g proteins which stimulate or inhibit intracellular signalling pathways. (signal transcution very similar to muscarinic receptors)

alpha 1: location and action

mostly smooth muscle of peripheral blood vessels, eye, arrector pili

via PLPc, increases IP3 and thus free Ca. results in excitation, vasoconstriction, pupil dilation


beta 1

location: mostly cardiac muscle tissue and kidney


action: via Ad. cyclase and cAMP. increased heart rate and contraction, renin release

beta 2

in smooth muscle of coronaries, bronchi


action: via ad. cyclase and cAMP. relaxation and vasodilation

beta 3

found in adipose tissue.


action: lipolysis

alpha receptors

when activated, generally produce exitatory responses of smooth muscles in which they are located

beta receptors

when activated generally produce inhibitory responses of smooth muscle in which they are located

complex phyisological responses result from

catecholamine stimulation because there are multiple receptor types which are differentially expressed in different tissues and cells.