Chapter 11

Peripheral Nervous System

Peripheral Nervous SystemOutline

Introductory Comments

1. Autonomic Nervous System Parasympathetic versus sympathetic nervous systems

2. Somatic Nervous System

3. Adrenal Gland & Modified ANS

4. Chemical Anatagonists & Agonists

5. Neurotoxins

ANTAGONISTIC

Exception to the rule

1. Sweat gland and vascular smooth muscle only sympathetic innervation

2. Cooperativity between sympathetic and parasympathetic

Autonomic Nervous System Controls

Found in Smooth Muscle

Found in Glands

Found in Cardiac muscle

sympathetic and parasympathetic neurons differ in several ways.

Site of ganglion• Length of pre and post-ganglionic fibers• Type of neurotransmitters released• pharmacologically

Divergence can occur

model of the autonomic pathway

“intrinsic neurons modulate”

Adrenal Medulla release primarily Epi.

Parasympathetic

Sympathetic

Sympathetic

Autonomic Nervous System

Length of the fibersSpinal cord

Ach

AchAch

NE

Adrenal Medulla release primarily Epi.

Parasympathetic

Sympathetic

Sympathetic

Autonomic Nervous SystemNeurotransmitters

Ach

Ganglion in circles

Spi

nal c

ord

TIS

SU

E

Autonomic Division of Acetylcholine Receptor

Acetylcholine Receptor

inotropic receptorchange ion channels

Located in:Autonom ic ganglia of PS and Sym

Nictonic Cholinergic

m etabotropic receptorvia G protein

Located in:Neuroeffector junction of PS

M uscarinic Cholinergic(at least 5 types)

Cholinergic

Autonomic Division of Adrenergic Receptor

Norepinephrine Receptor

m etabotropic receptorsecond m essengers

A reas not innvervatedby sym pathetic neurons

beta-2 receptors

m etabotropic receptorsecond m essengers

Located in:cardiac and kidney

B eta-1 adrenergicType title here

m etabotropic receptorsecond m essenger

Found on m ost target tissue ofsym pathetic nervous system

alpha-1

A drenergic

Cholinergic Antagonists

Muscarinic Nicotinic

Atropine, scopolamine Alpha-bungarotoxin (at muscle only, curare)

Adrenergic Antagonists

Alpha Beta

Alpha blockers Beta blockers: propranolol (B1 and B2) and

metaprolol is B1 only

AchSomatic

Somatic Nervous System

Neuromuscular Junction

Always Excitatory!

Single neuron!

Let’s take a minute to look at the unique adrenal gland.

What other structure that we studied hastwo different embyronic origins?

Summary

Natural neurotoxins

Funnel web spider, Agelenopsis aperta

Blocks voltage gated Ca++

TTX blocks Na+ channels

Bungarus multicinctus Blocks Acetylchoine receptors Fish hunting cone snail, Conus geographus

Block Ca++ channels

Blocks exocytosis

Botulism Toxin

Botox

Stimulant

Binds to acetylcholine receptors

Acetylcholine receptor

Summary: Effect of ANS on Various Physiological Systems

Reproductive

Digestive tract

Lungs

Arterioles and veins

Salivary G lands

Pupil

Heart

Effector O rgan

erection

increased m otility

bronchioles constrict

no effect

w atery secretion

constricts

Slow s rate

PS

ejaculation

decreased m otility

bronchioles dialate

constricts (alpha)dilates (beta-2)

m ucus secretion

dilates

increase rate and force

Sym pathetic

THE END