Human Physiology

1
Chapter 9
The Autonomic Nervous System
2
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

3
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
4
C. Divisions of the ANS

• 1. 2 DIVISIONS-
• sympathetic - ___________________________
• parasympathetic- _____________________

a. sympathetic

• characterized by _____________________ which
  cause Symp to mostly act as a unit (_______
  ____________________)

5

• 1. _____________ preganglionics branch to
  synapse with many postganglionic neurons

Fig 9.3
2. ____________ postganglionics receive synaptic
input from large number of preganglionics
6
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

7
3. Sympathoadrenal System continued

• Epi is made by methylating Norepi

Fig 9.8
8
__________ innervates heart, lungs, esophagus,
stomach, pancreas, liver, small intestine,
upper half of the large intestine
b. parasympathetic

• 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

_________________ from S2-4 innervate lower half
of large intestine, rectum, urinary
reproductive systems
9
D. ANS Neurotransmitters
Fig 9.7

• Both Symp Parasymp preganglionics release ACh
• Parasymp postganglionics also release ____
• Called __________ synapses
• Most Symp postganglionics release ________
• (noradenaline)
• Called ___________ synapses

para.
Symp.
para.
10
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

11
1. Adrenergic Stimulation
Fig 9.10

• useful drugs affect ANS receptors
• _________ promote NT actions
• __________ inhibit NT actions

12
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 ________________

13
Fig 9.11
14
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

15
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 __________________

16
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