Neurophysiology; Autonomic Nervous System

Question 1

True or false: survival is possible without the ANS

Answer 1

true

Question 2

Major function of ANS

Answer 2

homeostasis

Question 3

Differences between preganglionic and postganglionic neurons

Answer 3

Preganglionic neurons made of B fibers which are small diameter (relative to A delta fibers) and myelinated

post-ganglionic neurons made of C fibers which are also small diameter, but are mostly unmyelinated

Question 4

Differentiate the 5 types of muscarinic receptors

Answer 4

M1, M3, and M5 are excitatory

M2 and M4 are inhibitory

Question 5

Difference between muscarinic and nicotinic receptors

Answer 5

All nicotinic receptors are excitatory; muscarinic receptors can be both excitatory and inhibitory

Nicotinic receptors are ionotropic: activation = depolarization; muscarinic receptors are metabotropic: are G-protein coupled

Nicotinic receptors cause fast EPSPs on postganglionic neuron; muscarinic receptors result in slow EPSPs (decreased membrane conductance)

*Difference is in their mechanism of action, but both bind acetylcholine (are cholinergic)

Question 6

Describe the subtypes of adrenergic receptors and the effects of the agonist binding

Answer 6

Alpha; alpha 1 is excitatory; binding of agonist = activation of Gq coupled protein = increase in calcium = muscle contraction

alpha 2 is inhibitory; agonist binds = activation of Gi coupled protein = decrease in cAMP

beta receptors are generally excitatory; agonist binds = increase in cAMP