4. Peripheral Nervous System

Vocabulary flashcards covering key terms of the peripheral nervous system, nerve plexuses, reflex physiology, cranial nerves, and autonomic nervous system including neurotransmitters and receptors.

Peripheral Nervous System (PNS)

All nervous tissue outside the brain and spinal cord; composed of spinal nerves and cranial nerves.

Spinal Nerves

31 pairs of mixed nerves that emerge from the spinal cord

Contains Botha sensory (coming in) and motor axons (coming out)

Nerve is

Made of bundles of axons

Sensory (Afferent) Axon

Nerve fiber that carries information toward the CNS.

Motor (Efferent) Axon

Nerve fiber that carries commands away from the CNS to effectors.

Epineurium

Cover entire nerve

Perineurium

surrounds bundles of axons called fascicles

Endoneurium

surrounds individual axon within a nerve

Nerve Plexus

Network of nerve fibers

Cervical Plexus

Neck and head area C1-C5

• Includes phrenic nerve : supplies diaphragm

Brachial Plexus

Supplies upper limbs arms C5-T1

• Major nerves : axillary, radial, ulnar

Lumbar Plexus

lower abdominal, medial and anterior portion of thigh L1-L4

• femoral nerve : supplies front and medial of thigh

Sacral Plexus

Sacral region L4–S4

• Sciatic nerve : supplying back of thigh and legs ( biggest nerve in body )

Ganglion

Group of neuron cell bodies in the PNS

Reflex

Rapid, predictable, involuntary motor response to a stimulus.

Two types of reflexes

Visceral (conditioned) reflexes - affect glands, cardia muscles, smooth muscles, required prior thought or learning

Somatic (simple) reflexes - unconscious skeletal muscle motor responses

Components of a reflex arc (5)

1. Receptor

Placing hand on hot stove stimulates sensory receptor

2. Sensory Neuron

Take information to spinal cord or brain (CNS)

3. Integration

whats going to happen what’s the meaning for this

4. Motor Neuron

carries information out/order out to take to effect organ

5. Effector

Muscle or gland that performs the reflex response

How many cranial nerves are there

12

Cranial Nerve I: Olfactory

Sense of smell

Cranial Nerve II: Optic

Carries visual information from your retina to the brain

Cranial Nerve III: Oculomotor

Controls eye movement

Cranial Nerve V: Trigeminal

Mixed nerve; provides facial sensation and muscles of mastication.

Cranial Nerve VIII(8): Vestibulocochlear

Responsible for the senses of hearing and balance

Cranial Nerve X(10): Vagus

supplies heart, lungs, and abdominal organs

Autonomic Nervous System (ANS)

Involuntary motor division controlling smooth muscle, cardiac muscle, and glands.

AND regulated many internal organs through two divisions

Sympathetic & parasympathetic division

Sympathetic division “thoracolumbar division”

Fight or flight, use only under stress or emergency

Ganglia 2

Sympathetic chain ganglia

Collateral ganglia

Parasympathetic division “Cranionsacral division”

Rest and digest, use all the time, not under stress

Ganglia 2

Terminal ganglia

Intramural ganglia

Changes to your body during sympathetic response

Hair stand up

Pupils dilate

Sweating

Dry mouth

Respiration rate increases

Heart rate increases