Transcript Human Physiology

Chapter 9
The Autonomic Nervous System
A. Overview
____________________
(ANS) manages our
physiology
By regulating _________________, & their smooth
muscles & glands
Smooth
muscle maintains resting tone in absence of
nerve stimulation
Many types of smooth are ________________ &
contract rhythmically without ANS input
B. Autonomic Neurons
 ANS
has
____________ in
its ___________
pathway
 1st neuron (=
___________) has
cell body in brain
or spinal cord
_______________
axon extends from
autonomic ganglion
to target tissue
Fig 9.1
C. Divisions of the ANS
1. 2 DIVISIONS sympathetic - ___________________________
 parasympathetic- _____________________
a. sympathetic
characterized
by _____________________ which
cause Symp to mostly act as a unit (_______
____________________)
1. _____________: preganglionics branch to synapse
with many postganglionic neurons
Fig 9.3
2. ____________: postganglionics receive synaptic input
from large number of preganglionics
3. Sympathoadrenal System
The
_______________, on top of kidney, appears to
be a modified collateral ganglion
-modified ______________
release 85% ___________ (Epi) &
15% ______________ (Norepi) into blood in
response to preganglionic stimulation
Stimulated during mass activation
3. Sympathoadrenal System continued
Epi
is made by methylating Norepi
Fig 9.8
b. parasympathetic
 Is
__________ innervates heart, lungs,
esophagus, stomach, pancreas,
liver, small intestine, & upper half of
the large intestine
also called
________________
because long
preganglionics originate
in midbrain, medulla,
pons, & S2 - S4
 Synapse on
postganglionic in
_________________
located next to or
within target organ
 Postganglionic has
short axon that
innervates target
_________________ from S2-4
innervate lower half of large
intestine, rectum, urinary &
reproductive systems
D. ANS Neurotransmitters
 Both
Symp &
Parasymp
preganglionics
release ACh
para.
 Parasymp
postganglionics also
release ____
 Called __________
synapses
 Most Symp
Symp.
postganglionics
release ________
 (noradenaline)
 Called
___________
para.
synapses
Fig 9.7
1. Adrenergic Stimulation
 Causes
both _________ & _________ depending on tissue
 Because of different subtypes of receptors for same NT
 2 major subtypes are  &  _____________ receptors
 Each has own subtypes: 1, 2 & 1, 2
1. Adrenergic Stimulation
Fig 9.10
 useful
drugs affect
ANS receptors
 _________
promote NT
actions
 __________
inhibit NT actions
2. Cholinergic Stimulation
 ACh
is used at all motor neuron synapses on skeletal
muscle, all __________, & Parasymp postganglionics
 Cholinergic receptors have 2 subtypes:
 _____________ which is stimulated by nicotine;
 blocked by ___________
 ________________which is stimulated by muscarine
(from poisonous mushrooms);
 blocked by ________________
Fig 9.11
E. Other ANS NTs
Some
___________ are do not use _____ or ___
Called nonadrenergic, noncholinergic fibers
Appear to use ATP, VIP, or NO as NTs
NO produces smooth muscle relaxation in
many tissues
F. Organs With Dual Innervation
Most
visceral organs receive ______________
(supplied by both Symp & Parasymp)
2 branches are usually ______________, such as
their effects on heart rate
Can be ________________ (cause similar
effects) such as with salivation
Or __________________ (produce different
effects that work together to cause desired
effect) such as with __________________
G. Control of the ANS by Higher Brain
Centers
________
most directly controls activity of ANS
It has centers for control of cardiovascular,
pulmonary, urinary, reproductive, & digestive
systems
_______________ has centers for control of body
temperature, hunger, & thirst; & can regulate
medulla
_______________ is responsible for visceral
responses that reflect ____________states
______________ & cerebellum also influence ANS