Anatomy: PNS & ANS

Question 1

What are Cranial Nerves & their importance?

Answer 1

Come from and to the brain stem
Include nerves that are PURE sensory and motor info, and some nerves that are mixed with both sensory and motor.
Ex: Olfactory Nerve (Purely Sensory), Oculamotor Nerve (Purely Motor), Trigeminal nerve (Mixed).

Question 2

What is a Dermatome?

Answer 2

A specific area of skin that is mainly supplied by a single spinal nerve.
Helps give an idea to where referred pain locations are – to give diagnoses.

Question 3

What is a reflex arc?

Answer 3

PNS (sensory afferent division) detects stimulus and sends it to CNS
CNS interprets and processes information, and
PNS (motor efferent division) sends motor response from CNS to effectors

Question 4

What is the Flexion-crossed extension reflex?

Answer 4

Pain detection: Sensory nerve (nociceptive afferents) takes in stimulus and sends it to spinal cord.
Ipsilateral flexion: The affected limb FLEXES to withdraw from the painful stimulus.
Contralateral extension: The opposite limb extends to provide stability and maintain balance.

Question 5

ANS vs Somatic Nervous System

Answer 5

Somatic:
Uses just skeletal muscle as a target
only uses acetylcholine as its neurotransmitter
always voluntary
one NEURON (motor efferent) signal

Autonomic:
Uses smooth muscle, cardiac muscles, or glands
Uses acetylcholine and norepinephrine as neurotransmitters
is involuntary
needs a 2-neuron chain to send a signal (pre-ganglionic and post ganglionic neuron.

Question 6

Sympathetic vs Parasympathetic (ANS)

Answer 6

Sympathetic:
Fight or Flight
Occurs in thoracic and/or lumbar spinal cord
Has the 2 neuron chain
Ganglion is closer to spinal cord so pre-ganglionic is short and post is long
Uses acetylcholine in pre and post ganglionic AND norepinephrine in post ganglionic.

Parasympathetic:
Rest and digest, chillin
Occurs in brainstem and/or sacral spinal cord
Has the 2 neuron chain
Ganglion is farther from spinal cord so pre-ganglionic is long and post is short
Uses acetylcholine in pre and post ganglionic

Question 7

What’s a Ganglion?

Answer 7

Group of Cell bodies OUTSIDE of the CNS.

Question 8

What’s a pre-ganglionic neuron?

Answer 8

Comes from the spinal cord top the ganglion. Uses acetylcholine

Question 9

Whats a post-ganglionic neuron?

Answer 9

Comes from the ganglion TO the target cell.