The Peripheral Nervous System (PNS)

What is the PNS?

The network of nerves from the brain and spinal cord that act as communication to bridge between the CNS and body

What are the two major divisions?

Somatic nervous system and Autonomic nervous system

What does the Somatic Nervous System do (SNS)?

Controls voluntary movements

- Connects CNS to skeletal muscles, skin receptors, and sense organs

- Responsible for conscious activites

- Use motor and sensory neurons

What does the Autonomic Nervous System do (ANS)?

Controls involuntary actions

- Regulates internal organs

- Maintains body's automatic functions

What are the two subdivisions of the ANS?

Sympathetic and Parasympathetic

What does the sympathetic division of the ANS do?

- Fight or flight response

- Activates during stress

- Uses norepinephrine as primary neurotransmitter

What are some of the effcts of the sympathetic division?

Increased heart rate, dilated pupils, enhanced metabolism, and decreased digestion

What does the parasympathetic division of the ANS do?

- Rest and digest response

- Activates during calm states

- Uses acetylcholine as primary neurotransmitter

What are some of the effects of the parasympathetic division?

Decreased heart rate, constricted pupils, enhanced digesttion, and reduced blood pressure

What are the types of neurons in the PNS?

- Sensory neurons (Afferent)

- Motor neurons (Efferent)

- Mixed nerves

- Interneurons

What are cranial nerves?

12 pairs of nerves in the PNS that are connected to the brain to control:

- Facial expressions

- Eye movement

- Hearing

- Taste

- Smell

What are spinal nerves?

31 pairs of nervse in the PNS connected to the spinal cord that control the rest of the body through different regions:

- Cervical (8)

- Thoracic (12)

- Lumbar (5)

- Sacral (5)

- Coccygeal (1)