Chapter 10: Peripheral nervous system

Branching from the spinal cord, how many pairs of spinal nerves are there?

31

What do the 31 spinal nerves do?

innervate the limbs and trunk of the body.

Efferent

Motor, away

Afferent

Sensory, towards.

Posterior root and anterior root

contains axons containing sensory innervation

Posterior ramus

Innervates the muscles, joints, and skin of the back. Does not form plexuses, this controls muscles and movement in the back.

Anterior ramus

Innervates the muscles and skin of the anterior and lateral parts of the trunk, as well as the limbs. Forms plexuses (cervical, brachial and lumbosacral) Controls movement and sensation in majority of the body

Dermatome

An area of skin supplied by a single spinal nerve

atlantooccipital joint

the articulation between the atlas (C1 vertebra) and the occipital bone of the skull. It plays a crucial role in head movement and stability.

How many pairs of cervical spinal nerves do we have?

8

How many pairs of Thoracic spinal nerves do we have?

12

What is the 1rst cranial nerve?

Olfactory

What is the 2nd cranial nerve?

Optic

What is the 3rd cranial nerve?

Oculomotor

What is the 4th cranial nerve?

Trochlear

What is the 5th cranial nerve?

Trigeminal

What is the 6th cranial nerve?

Abducens

What is the 7th cranial nerve?

Facial

What is the 8th cranial nerve?

Vestibulocochlear

What is the 9th cranial nerve?

glossopharyngeal

What is the 10th cranial nerve?

vagus

What is the 11th cranial nerve?

accessory

What is the 12th cranial nerve?

hypoglossal

What does the olfactory do?

Provides special sensory innervation of smell

What does the optic cranial nerve do?

Special sensory innervation of sight

What does the oculomotor cranial nerve do?

Innervation to four of the six extraocular eye muscles. Helps movement of the eye

What does the trochlear do?

Innervates one of the six extraocular eye muscles.

What does the trigeminal do?

Carries both sensory and motor nerve fibers. Allowing sensation

What does the abducens do?

Motor innervation only and controls the sixth extraocular eye muscle.

Which nerves control muscles that move the eyeballs?

Oculomotor, Trochlear and Abducens

What does the facial nerves do?

Controls the muscles of facial expressions

What does the vestibulocochlear do?

Provides sensory innervation of hearing and balance

What does the glossopharyngeal do?

Controls the secretion of saliva, and sensory of taste from the tongue to the brain

What does the Vagus do?

allows for movement of the muscles in the throat, controls movement in digestive tract, slows heart rate, and this is the only cranial nerve that leaves the head and neck region.

What does the accessory do?

Controls movement of two muscles in the neck (sternocleidomastoid and trapezius)

What does the hypoglossal do?

controls the muscles of the tongue

Terminal nerve branch

A nerve that will ultimately innervate a muscle.

Phrenic

Located in the cervical plexus, plays a vital role in respiration by innervating the diaphragm, the primary muscle responsible for breathing.

Median nerve

Within the brachial plexus, innervates the muscles within the anterior forearm. This is associated with carpal tunnel syndrome

Femoral nerve

Within the lumbar plexus, innervate muscles of the anterior thigh

Sciatic nerve

Within the acral plexus, provides innervation to all posterior thigh muscles.

Sensory receptor

Detects the stimulus

What is the reflex arc?

The nerve pathway of the reflex

Somatic reflex

When the effector organ that responds is a skeletal muscle (drs hit your knee to test this)

Visceral reflex

Effector organ that responds is smooth muscle, cardiac muscle or a gland

Baroreceptors

Stretch sensors located in the walls of blood vessels. detects change in blood pressure

Stretch reflex

involuntary and rapid muscle contraction in response to muscle stretching

What is the purpose of the flexor reflex?

To remove a body part from a potential injury.