Ch. 6

Question 1

Somatic Nervous System vs Autonomic Nervous System

What do the control? Subdivisions?

Answer 1

Somatic: Things that are under our concious control. Usually involves skeletal muscle. No ganglion located here

ANS: Not under our conscious control. Has three subdivisions:
1. Sympathetic
2. Parasympathetic
3. Enteric- “gut feeling”

Question 2

SNS

Fight or Flight

Answer 2

-This includes our “fight or flight” response (Ergotopic)
-Increase HR, increased BP, dilates bronchioles, shunts ~75% of blood to skeletal muscles. This needs to be continuously stimulated in order to get this response
-

Question 3

PNS

Rest and Digest

Answer 3

-Conserve energy (lower HR, BP, RR)
-Shunts blood to endocrine, GI, urogenital
-Only needs to be stimulated once, short lived response
-Trophotropic

Question 4

SNS

Anatomy, Primary Neurotransmitter

Answer 4

-Arise from the CNS at the level of the T-Spine (T1-L2) or Thoracolumbar spine
-The sympathetic chain is a collection of cells called ganglia that receive information and deliver it to their target organ
-Short preganglionic fibers originate in the chain ganglia at the level of the spine
-Long post-ganglionic fibers that innervate and terminate at their target organ
-Primary neurotransmitter is norepinephrine (adrenergic)
-Adrenal glands will also release epinephrine

Question 5

PNS

Anatomy, Primary neurotransmitter

Answer 5

-Nerves located in the craniosacral area (Cranial nerves except II)
-Long preganglionic fibers. Leave the CNS through the cranial nerves and sacral spinal roots
-Short postganglionic fibers, terminate on the target organ
-Ganglia are located in visceral organs
-Most important cranial nerve here is X (Vagus)
-> 75% of the PNS output goes through the vagus nerve
-Primary neurotransmitter is ACh (cholinergic)

Question 6

Sympathomimetics

Direct acting vs indirect. What do these drugs do?

Answer 6

-Drug class that mimics the SNS
-Direct acting drugs: Epinephrine, isoproteronol, albuterol
-Indirect acting drugs: Ephedrine and amphetamines
-> Release stored NE, block reuptake or reverse the NET (transporter)
-Constricts blood vessels, inotropic & chronotropic cardiac effects, decrease bronchiole tone, decrease uterine tone (preterm labor)

Question 7

Sympatholytics

Drug subcategories, what do these drugs do?

Answer 7

-Inhibit the SNS
-Alpha blockers, beta blockers, non-specific blockers
-Decrease BP, HR

Question 8

Autonomic Receptors

Cholingeric vs Adrenergic Receptors

Answer 8

-ACh binds to these receptors
-Muscarinic
-Nicotinic

-Norepinephrine is the primary binding neurotransmitter
-Alpha
-Beta
-Dopaminergic

Question 9

Cholinergic Receptors

Muscarinic vs Nicotinic

Locations. Excitatory or inhibitory?

Answer 9

Muscarinic:
M1- (E) CNS neurons, SNS postganglionic neurons
M2-(I) Myocardium, smooth muscle, CNS
M3- (E) Exocrine glands, vessels, CNS
M4- (I) CNS, vagal nerve endings
M5- (E) Vascular endotheliam (esp. cerebral vessels), CNS

Nicotinic:
Nn: Neuronal; postganglionic neurons
Nm: Muscular; skeletal muscle

Question 10

Adrenoreceptors

A1

Answer 10

-Gq Receptor Pathway
Activates phospholipase C–> IP3 & DAG–> IP3 stimulates release of Ca++ into cytosol–> increased levels of myosin light chain kinase
DAG + Ca++ –> activate protein kinase C–> inhibits myosin light chain phosphatase
Both resulting in muscle contraction