Autonomic Nervous System

Question 1

Autonomic nervous system

Answer 1

-“self governing”, but not independent of the CNS.

Question 2

General Functions of the ANS

Answer 2

• regulates activity of cardiac muscle, smooth muscle, and some types of glands.
• maintains homeostasis: stabilization of life support systems.

Question 3

General Anatomic features of the ANS

Answer 3

A). composed primarily of motor neurons

B). features two neurons between CNS and effector:
CNS–>preganglionic fiber–>ganglion——>postganglionic fiber–>effector

C). two antagonistic divisions

   1. sympathetic ("accelerator"): excitatory
   2. parasympathetic ("brake"): inhibitory

D) features dual motor intervention, wherein every effector is supplied with one sympathetic and one parasympathetic fiber.
-exceptions: adrenal gland, sweat glands, arrector pili, and most blood vessels receive only sympathetics

Question 4

control of the ANS

Answer 4

A). Hypothalamus

• controls ANS, actions of medulla, thermoregulation, plus food and water intake.
• posterior hypothalamus= sympathetic center
• anterior hypothalamus= parasympathetic center

B). Medulla
-controls respiration, heart activity, blood pressure, and G.I. secretions

C). Cerebral cortex
-certain psychological states (biofeedback, yoga) can influence hypothalamus, hence the ANS