STRUCTURAL AND FUNCTIONAL ORGANIZATION OF THE AUTONOMIC NERVOUS SYSTEM

Question 1

Somatic Nervous System

Answer 1

(1) Controls skeletal muscle
(2) Conscious, voluntary control
(3) Motor pathway: one neuron from CNS to effector
(4) Does include sensory neurons (from skin, skeletal muscles, and special sense organs)
(5) All release the neurotransmitter acetylcholine (Ach)
(6) The axon of a single somatic motor neuron extends from CNS all the way to skeletal
muscle fibers

Question 2

Somatic Sensory Pathway

Answer 2

Relay sensory information from periphery to the cerebral cortex

Question 3

Cell body #1 are located where

Answer 3

in dorsal root ganglion

Question 4

Cell body #2 are located where

Answer 4

in spinal cord or brain stem

Question 5

Cell body #3 are located where

Answer 5

in thalamus; axon extends to cerebral cortex (somatosensory area in
postcentral gyrus)

Question 6

Posterior column - medial lemniscus pathway senses

Answer 6

Senses touch, pressure, vibration, and conscious proprioception

Question 7

Anterior spinothalamic tracts are responsible for what sensations

Answer 7

1) Light touch sensation
2) Deep pressure sensation

Question 8

Lateral spinothalamic tract are responsible for what sensations

Answer 8

1) Pain Sensation
2) Temperature (hot vs cold) sensation

Question 9

Somatic Motor Pathways
Signals come from:

Answer 9

(a) Upper motor neurons: Via corticospinal tracts
(b) Basal ganglia: Help with muscle tone
(c) Cerebellum: Coordination
(d) Sensory neurons or interneurons via reflexes

Question 10

Somatic Motor Pathways
Impulses activate lower motor neurons

Answer 10

Axons –> ventral root –> spinal nerve –> muscle –> voluntary movements

Question 11

Corticospinal Tract
Where is Upper Motor Neuron

Answer 11

1) Originates in the primary motor cortex (Precentral Gyrus)
2) Synapses with a lower motor neuron of appropriate spinal level

Question 12

Corticospinal Tract
Where is Lower Motor Neuron

Answer 12

1) Exits spinal ventral root to the muscle for movement

Question 13

What is the Autonomic Nervous System

Answer 13

(1) Regulated by hypothalamus and brainstem
(2) Controls viscera: Smooth and cardiac muscle, and sweat and digestive glands
(3) Unconscious, involuntary
(4) Motor pathway: Series of two neurons from CNS to effector
(5) Does include sensory neurons (monitors viscera)
(6) Two divisions: Sympathetic and parasympathetic
(7) Release either acetylcholine (ACh) or norepinephrine (NE)

Question 14

Autonomic Nervous System are split into 2

Answer 14

Sympathetic (S) division + parasympathetic (P) division

Question 15

Sympathetic (S) division responsibilities

Answer 15

Heart rate: S stimulates
S: “flight or fight,
Sweat glands, many blood vessels, hair muscles

Question 16

parasympathetic (P) division responsibilities

Answer 16

Digestive organs: P stimulates
P: “rest and digest”

Question 17

Autonomic motor pathway includes two motor neurons what are they

Answer 17

(preganglionic and
postganglionic neurons)

Question 18

Sympathetic preganglionic neurons

Answer 18

T1-L2
“thoracolumbar division” - lateral grey horn

One sympathetic preganglionic axon can synapse with 20 or more
postganglionic neuron cell bodies

Question 19

Preganglionic neuron is located

Answer 19

from CNS to neuron in ganglion

Question 20

Postganglionic neuron is located

Answer 20

from cell body in ganglion to effector

Question 21

Sympathetic preganglionic neurons:
Sympathetic trunk ganglion

Answer 21

Wides spread response

Question 22

Postganglionic neuron releases what

Answer 22

Release epinephrine and norepinephrine