Anatomy- Peripheral Nervous System

Central nervous system 
-The central nervous system contains the brain and spinal cord

Peripheral nervous system 
- The peripheral nervous system contains all nervous tissue outside of the CNS. It can be broken down into the Somatic nervous system (control skeletal muscles) and the Autonomic nervous system (regulates glands, blood vessels, and internal organs).
- It keeps the body in adjustment with the outside world.

Autonomic nervous system
- Maintains internal balance
- Regulates glands, blood vessels, and internal organs
- Maintains steady state within body automatically (ex. constant body temperature, regulates heart beat)

Sympathetic nervous system
- Prepares body for action
- Most active during stressful situations

Parasympathetic nervous system
- Helps return body to resting conditions
- Most active during periods of calm and physical rest

Cranial nerves
- There are 12 pairs, which all emerge from the brain.
- They transmit information from sensory receptors to the brain, and then transmit orders from the CNS to the muscles and glands.
- They are usually mixed nerves (a combination of afferent (sensory) and efferent (motor) nerurons).

1- Olfactory (sensory)- for smelling
2- Optic (sensory)- for vision
3- Oculomotor (motor)- eye movement
4- Trochlear (motor)- eye movement
5- Trigeminal:
     - Opthalmic (sensory)- face and scalp sensation
     - Maxillary (sensory)- mouth and nose sensation
     - Mandibular (mixed)- chewing
6- Abducens (motor)- eye movement
7- Facial (mixed)- face and scalp movement, tongue taste sensation, ear pain and temperature
8-Vestibulocochear (sensory)- hearing and equilibrium
9- Glossopharyngeal (mixed)- ear pain and temperature, tongue and throat sensations, throat movement
10- Vagus (mixed)- sensations in the throat, voice box, chest, abs. Movement in the voice box, throat, chest, abdominal viscera.
11- Accessory (motor)- neck and back movement
12- Hypoglossal (motor)- tongue movement

Spinal nerves
- These are all mixed nerves, and there are 31 pairs.
- 8 pairs of cervical spinal nerves (c1-c8)
- 12 pairs of thoracic spinal nerves (t1-t12)
- 5 pairs of lumbar (L1-L5)
- 5 pairs of sacral spinal nerves (s1-s5)
- 1 pair of cocygeal spinal nerves

Plexus 

- Cervical plexus: receives sensory information from the back of hear, neck, shoulders and upper chest
- Sends impulses to muscles of neck and shoulders
- Phrenic nerve arises from the cervical plexus and sends impulses to diagram

- Brachial Plexus: Supplies shoulder, arm, and hand.
- Ulnar and radial nerves emerge from here

- Lumbar Plexus: Supplies lower abdominal wall, buttocks, thigh, and genitals.
- Femoral nerve arises from here

-Sacral plexus: Supplies the thigh, leg, and foot
- Contains the sciatic nerve (largest nerve in the body)