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