Chapter 9 PNS Physiology

Question 1

Autonomic PNS involves?

Answer 1

-Vascular tone, -heart rate, contractility -pupillary constriction, -sweating, -salivation -piloerection (Goosebumps) -uterine contraction -GJ motility -Bladder function -Sympathetic and parasympathetic

Question 2

PNS is split into what branches?

Answer 2

-Autonomic (involuntary) -Sensory and somatic (voluntary)

Question 3

Two main neurotransmitters used in the periphery

Answer 3

-Acetylcholine -Norepinephrine

Question 4

Function of Ach

Answer 4

-Stimulates nicotinic AChR (nAChR) on sympathetic, parasympathetic and NMJ (somatic) -Stimulates muscarinic receptors (m1, M2, M3, etc)

Question 5

Function of Norepinephrine

Answer 5

-Stimulates a-&B- adrenegic receptors on tissues innervated by sympathetic postganglionic neurons (a1, a2, b1, b2 etc)

Question 6

Types of Cholinergic receptors

Answer 6

-Muscarinic (mAChR) -Nicotinic (nAChR)

Question 7

Muscarinic (mAChR) receptors

Answer 7

-G protein linked -locations: Most: Terminal synapses of all parasympathetic postganglionic fibers (cardiac, smooth muscle); Sympathetic postganglionic fibers (sweat glands); CNS (sympathetic nervous system)

Question 8

Nicotinic (nAChR)

Answer 8

-Ligand-gated ion channels -Locations: Postsynaptically at excitatory autonomic synapses CNS (in the brain on various neurons) NMJ (somatic, skeletal muscle)

Question 9

Adrenergic Receptors

Answer 9

G protein linked locations: : Terminal synapses of all sympathetic postganglionic fibers (vascular, cardiac, smooth muscle, gland, nerve terminals) CNS

Question 10

Adrenergic Receptor function

Answer 10

• Sympathetic nervous system (homeostasis)
• Endogenous ligands are Catecholamines (Norepinephrine, Epinephrine, Dopamine)
  
  • Alpha and Beta receptors are all G-protein linked α1, α2, β1, β2
• Physiological Roles:
  
  • Increasing rate and force of cardiac contraction
  • Modifying the peripheral resistance of the arterial system (blood pressure)
  • Stimulating hepatic release of glucose Increasing adipocyte release of free fatty acids