Lec 7: Autonomic nervous system

Visceral motor: no conscious control
(Smooth muscle, rather than skeletal)

• Sympathetic: fight/flight: ↑heart rate
• Parasympathetic:Rest&Digest: relaxed

preganglionic cell bodies in thoracic lumbar region of spinal cord send projections to puravertebral SNS chain
postaganglionic cell bodies in SNS chain send long axonal projections that synapse on taget organ
output from sp.cord: collection to ganglion close to sp.cord

pregangionic cell bodies in cranial&sacral regions spinal cord send long axonal projections to PNS ganglia
postganglionic cell bodies send short axonal projections which synapse on target organs
ganglion close to effector

HYPOTHALAMUS decide whether
SNS
controlled brainstem emotions
dilation of pupil=>better vision=>greater field of view=>wasted E=> if neede for sth else
more bl. circulation
store (liver) glu.
inhibit insulin
gland releases hormonal response relax bladder

PNS
Design to relax
salive->food digestion
major output of neuron from cranial
stimulate insulin: abs. glu.

Neurotransmitters (chemical) &receptors (chemical)->ANS

Somatic efferent inovate skeletal muscles

CNS----------------------------<>ACh NIC Sk.muscle

Sympathetic

----------<>ACh NIC----------<>NA Adr heart, bl.vessels e.t.c.

---------------------<>ACh NIC-----<> ACh Musc heart, smooth, glands

1)Nicotinic ACh receptos, glutamate, GABA: ligand gated ion channels

2)Adrenoreceptors&muscarinic receptors: G-protein-coupled receptors

• Adrenoreceptors subtypes (SNS): α, β

α1: constriction bl.vessels

α2: inhibit NE release

β1:↑heart rate

β2: opening bl.vessels

β3:break down lipids if E needed

• Muscarinic (PNS)

M1:neural, CNS

M2: cardia, heart

M3:grandular, smooth muscle

Physiological effects of ANS

Efficacy of heart-> quick pumping of heart

S:↑heart rate, P:↓ heart rate

Bl.vessels

controlled most by S (α1 constriction less bl.supply, β2 dilation)

lungs: S: relaxation, P: constriction

GI tract: S:↓motility,secretion,contriction, ability to digest food, P: ↑ ability digestion

sex organs: S: ejaculation, P: erection

bladder: S: constriction, motility, P: Dilation, ↑motility

skin: S: secretion, constriction

eye: S: dilation, better peripheral vision, P: relaxation

liver, fat cells, adrena medulla: S mostly

pancreas: S: inhibited, P: stimulated