Chapter 9 The Autonomic Nervous System. A. Overview ____________________ (ANS) manages our...
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Transcript of Chapter 9 The Autonomic Nervous System. A. Overview ____________________ (ANS) manages our...
Chapter 9
The Autonomic Nervous System
A. Overview ____________________ (ANS) manages our
physiologyBy 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
Fig 9.1
_______________ axon extends from autonomic ganglion to target tissue
C. Divisions of the ANS1. 2 DIVISIONS-
sympathetic - ___________________________ parasympathetic- _____________________
characterized by _____________________ which cause Symp to mostly act as a unit (_______ ____________________)
a. sympathetic
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 stimulationStimulated during mass activation
3. Sympathoadrenal System continued
Epi is made by methylating Norepi
Fig 9.8
Is 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
b. parasympathetic__________ innervates heart, lungs, esophagus, stomach, pancreas, liver, small intestine, & upper half of the large intestine
_________________ from S2-4 innervate lower half of large intestine, rectum, urinary & reproductive systems
D. ANS Neurotransmitters Both Symp &
Parasymp preganglionics release ACh
Parasymp postganglionics also release ____ Called __________
synapses Most Symp
postganglionics release ________
(noradenaline) Called
___________ synapses
Fig 9.7
para.
Symp.
para.
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
useful drugs affect ANS receptors _________
promote NT actions
__________ inhibit NT actions
Fig 9.10
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