Nervous System and Synaptic Transmisiion (Exam 2)

Question 1

What is the difference between afferent and efferent and what processes are in each

Answer 1

Afferent (going towards the CNS):
special sensory receptors- smell, taste, vision, etc
somatic receptors- joints, pressire, pain
visceral sensory receptors: internal organs, CV, Resp, etc
Efferent (goes away from the CNS):
Somatic (conscious): skeletal muscle
ANS: Sympathetic and Parasympathetic (smooth and cardiac muscle, and glands)

Question 2

What are the differences between Somatic and Autonomic

Answer 2

Somatic: sensory input ->CNS-> Motor neurons affect the skeletal muscle
all neuron cell bodies are in the CNS
Autonomic:
cell bodies inside the CNS is nuclei
cell bodies outside the CNS is ganglia

Question 3

What are the sympathetic responses of the ANS and what is it known as

Answer 3

increase HR and BP, dilate bronchioles, shunt blood to needed muscles
“fight-or-flight”

ergotropic
has to be continously stimulated

Question 4

What are the parasympathetic responses of the ANS and what is it known as

Answer 4

conserve energy, shunts blood to digestive, endocrine, urogenital
“rest and digest”

stimulated once

Question 5

Describe the anatomy of the Sympathtic NS

Answer 5

thoracolumbar nerves
short pre-ganglionic and long post-ganglionic
chain ganglion enables it to activate multiple ganglions

Question 6

Describe the anatomy of the Parasympathtic NS

Answer 6

Cranialsacral nerves
Pre-ganglionic is long and post-ganglionic is short
CN X: Vagus 75% of parasympathetic output

Question 7

What is the Enteric Nervous System

Answer 7

GI under the parasympathetic control
sympathetic acitivity is inhibitory

Question 8

How is the ANS different than Somatic

Answer 8

Axons are two-neuron chains
preganglionic release ACh and postganglionic release NE or ACh and effects are stimulatory or inhibitory
Somatic controls skeletal muscle

Question 9

What are sympathomimetics and how do they work

Answer 9

Drugs that mimic Sympathetic NS
Direct: Epi, NE, Isoproterenol, Albuterl
Indirect: ephedrine and amphetamines
effect: vasoconstriction, inotropic, chronotropic, bronchodilation, decrease uterine muscle tone

Question 10

What are sympatholytics

Answer 10

inhibit the sympathetic nervous system
alpha blockers: phentolamine
beta blocker: propanolol
mixed: labetolol

Question 11

What are the cholinergic receptors? Which are stimulatory and inhibitory

Answer 11

Activated by ACh
Muscarinc and Nicotinic
excitatory: M1, M3, M5
- activates Gq->PLC
inhibitory M2 M,4
- inhibits adenylate cyclase
Nicotinic: Nueronal and Muscular
-Ion channels

Question 12

What are the adrenergic receptors? how are they activated

Answer 12

GPCRs bind to endogenous and exogenous Epi and NE
Alpha 1: activates PLC (Gq)
Alpha 2: inhibits adneylate cyclase (Gi)
Beta 1, 2, 3: stimulates adenylate cyclases (Gs)

Question 13

Explain the Alpha-1 Gq pathway

Answer 13

NE binds to alpha 1 receptor->Gq activates PLC-> PLC makes the 2nd messengers (DAG & IP3)
IP3 binds to Ca channels in the SR -> Ca released increasing Ca influx into the cell-> activates MLCKinase-> phosphorylates Mysosin -> contraction -> increase BP
DAG-> activate PKC-> inhibits MLCPhospatase-> keeps myosin in active state (contracted)

Question 14

Explain the pathway of B1 activation in the heart

Answer 14

sympathetic nerve release NE-> NE binds to B1 receptor activated Gs-> Gs activates Adenyly Cyclase to convert ATP to cAMP ->activate PK-A-> bind to Ca channel in SR releasing Ca into the cell and membrane Ca channel open moving more Ca into the cell-> higher Ca leads to stronger contraction

Question 15

Explain the B2 pathway in the periphery

Answer 15

NE binds to B2 receptor-> activates Gs-> activates AC-> increases cAMP-> inhibits MLCKinase -> relaxation
located more in skeletal muscle

Question 16

What ate NANC Neurons

Answer 16

non-adregnergic, non-cholinergic
release different NTs
- NOS, substance P, somatostatin
- gut: ENS
sensory and motor