Autonomic neurotransmitters; Physiology of smooth muscle

Question 1

What is the function of the autonomic nervous system?

Answer 1

• regulation of nonconscious “autonomic” functions
• homeostasis of the body

Question 2

What are the divisions of the autonomic nervous system?

Answer 2

• parasympathetic
• sympathetic
• enteric nervous system

Question 3

What is the general scheme of the ANS?

Answer 3

Preganglionic neuron

(CNS)

↓

post-ganglionic neuron

(periperal ganglion)

↓

target cell

Question 4

What is the origin, ganglion, pre/post ganglionic axon of the parasympathetic nervous system?

Answer 4

Origin: Cranial nerves (III, VII, IX, X)

Sacral spinal cord (S2-S4)

Ganglion: near or within the organ

Preganglionic axon: long

postganglionic axon: short

Question 5

What is the origin, ganglion, pre/post ganglionic axon of the sympathetic nervous system?

Answer 5

Origin: Thoracic spinal cord (T1-T12)

Lumbar spinal cord (L1-L2/3)

Ganglion: close to the spinal chord (pre/post vertebral ganglia)

Preganglionic axon: short

Postganglionic axon: long

Question 6

What are the PREGANGLIONIC AXON transmitters and receptors of the parasympathetic and sympathetic NS?

Answer 6

Preganglionic axon transmitter: ACh

Preganglionic axon receptor: nAChR (nicotinic)

Question 7

What are the POSTGANGLIONIC AXON transmitters and receptors of the parasympathetic NS?

Answer 7

Postganglionic axon Transmitter: ACh (VIP, NO)

Receptors of the effector cells:

mAChR(M1-M5)

M1,M3,M5 (IP3, Ca2+) M2,M4 (cAMP ↓)

Question 8

What are the POSTGANGLIONIC AXON transmitters and receptors of the sympathetic NS?

Answer 8

Postganglionic axon Transmitter:

NE, ACh

NE-NPY – GI vessels NE-somatostatin

Receptors of the effector cells:

Adrenergic receptors

• alpha* 1 (IP3, Ca2+)
• alpha* 2 (cAMP↓)
• beta* 1 (cAMP↑)
• beta* 2 (cAMP↑)
• beta*3 (cAMP↑)

mAChR