Download Slides - gserianne.com

Visual Anatomy & Physiology
First Edition
Martini & Ober
Chapter 14
Autonomic Nervous System
Lecture 21
1
Autonomic (Visceral) Nervous System
Figure from: Hole’s Human A&P, 12th edition, 2010
CNS
PNS
2
Autonomic Nervous System
• functions without conscious effort
• controls visceral (squishy!) activities
• regulates smooth muscle, cardiac muscle, and glands
Two Main Divisions
• sympathetic – prepares body for fight or flight
situations
• parasympathetic – prepares body for rest and
digest activities
Third Division – Enteric Nervous System (ENS)
3
Somatic vs. Autonomic Nervous Systems
Dual
Figure from: Marieb, Human Anatomy & Physiology, Pearson Education, 2004
4
Autonomic Nerve Fibers
Figure from: Hole’s Human A&P, 12th edition, 2010
*ANS = a motor
division of the PNS
5
Sympathetic Division of ANS
*
Paravertebral ganglion
Effectors
in head
and
thoracic
cavity
Effectors in
muscles and
body wall
*
(T5 – T12)
*
Figure from: Saladin,
Anatomy & Physiology,
McGraw Hill, 2007
6
Sympathetic Division of the ANS
SYMPATHETIC
(Thoracolumbar
outflow)
Fight or Flight
“E” situations
Emergency
Embarrassment
Excitement
Exercise
Figure from:
Martini, Anatomy
& Physiology,
Prentice Hall,
2001
8
Spinal Nerves – Autonomic Fibers
Sympathetic
ganglion - cell bodies
of postganglionic
sympathetic neurons
*
Three fates of a
preganglionic
sympathetic axon:
*
1) synapse in same
chain ganglion
2) Ascend/descend to
synapse in another
chain ganglion
3) Pass through
without synapsing
(form prevertebral, or
collateral ganglia)
*
*
Figure from: Martini,
Fundamentals of
Anatomy &
Physiology, Pearson
Education, 2004
9
Sympathetic Division - Divergence
Figure from: Hole’s Human A&P, 12th edition, 2010
NOTE:
Arrangement of
nerves creates
DIVERGENCE
Sympathy spreads…
11
Parasympathetic
(Craniosacral
outflow)
“REST AND
DIGEST”
Salivation
Lacrimation
Urination
Digestion
Defecation
3 decreases
- Heart rate
- Airway diameter
- Pupil size (constrict)
Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004
12
Spinal Nerves – Visceral Sensory Fibers
*
Dorsal root - axons of
sensory neurons in
the dorsal root
ganglion
Dorsal root
ganglion - cell
bodies of sensory
neurons
*
*
Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004
13
Autonomic
Plexuses
Sympathetic collateral
(prevertebral) ganglia
Figure from:
Martini,
Fundamentals of
Anatomy &
Physiology,
Pearson
Education, 2004
14
Autonomic Neurotransmitters
Figure from: Hole’s Human A&P, 12th edition, 2010
= always excitatory in ganglia
You should know which neurotransmitters are
released, and the locations where they are released
15
Sympathetic Myoneural Junctions
NE is either:
Figure from: Martini, Fundamentals
of Anatomy & Physiology, Pearson
Education, 2004
- reabsorbed and
reused or broken
down by monoamine
oxidase (MAO) in
varicosities
- or broken down by
catechol-Omethyltransferase
(COMT) in
surrounding tissues
16
Actions of Autonomic Neurotransmitters
• depend on receptor
Cholinergic receptors
• bind acetylcholine
• nicotinic
• excitatory
• muscarinic
• excitatory or inhibitory
Adrenergic receptors
• bind norepinephrine
• alpha (Types 1 and 2)
• different responses on
various effectors
• beta (Types 1 and 2)
• different responses on
various effectors
17
Actions of Cholinergic Receptors
Cholinergic receptors
Nicotinic receptors 
always excitatory
Muscarinic 
Excitatory or inhibitory
Remember: the
RECEPTOR
determines the effect of
a neurotransmitter
(Sweat glands, blood vessels to skeletal muscles, brain)
Always
excitatory
18
Figure from: Hole’s Human A&P, 12th edition, 2010
Control of Autonomic Activity
Sympathetic and
Parasympathetic
Sympathetic
Parasympathetic
Figure from: Martini,
Anatomy & Physiology,
Prentice Hall, 2001
19
Review
• The autonomic nervous system (ANS)
–
–
–
–
–
Controls visceral activities involuntarily
Sympathetic (thoracolumbar) = fight or flight
Parasympathetic (craniosacral) = rest and digest
Efferent fibers synapse in ganglia outside CNS
NTx of the ANS
• Acetylcholine (cholinergic) – pre- and postganglionic
parasympathetic and preganglionic sympathetic
• Adrenergic (norepinephrine) – postganglionic
sympathetic ONLY
20
Review
Branch of ANS
PARASYMPATHETIC
SYMPATHETIC
General
Function
“rest and digest”
(SLUDD; 3 decreases)
“fight or flight”
(“E” situations)
Origin of
Preganglionic
fiber
from cranial region of brain
or sacral region of spinal
cord
(craniosacral outflow)
from thoracic or lumbar region
of spinal cord
(thoracolumbar outflow)
Length of
Preganglionic
fiber
long
short
Location of
Ganglia
within or near effector
alongside or in front of spinal
cord
NTx secreted by
postganglionic
fiber
acetylcholine
Norepinephrine
(some acetylcholine; sweat
glands, smooth muscle on
blood vessels, brain)
Know this chart
21