27.3 The Peripheral Nervous System

The Peripheral Nervous System

-Consists of all the nerves and associated cells that are not part of the brain or spinal cord.

The sensory division

transmits impulses from sense organs to the central The motor division system

The motor division

transmits impulses from the central nervous system to muscles or glands.

The motor division is divided into two divisions:

• The somatic nervous system

• The autonomic nervous system.

somatic nervous system

regulates body activities that are under voluntary, conscious control

Example: Movement of skeletal muscles.

autonomic nervous system

regulates activities that are involuntary, not under conscious control.

Example: When you start to run, the autonomic nervous system speeds up your heart rate

The autonomic nervous system consists of two parts…

The sympathetic nervous system

The parasympathetic nervous system

Sympathetic system

prepares the body for the “fight or flight” response.

Ex: Increase in heart rate & blood pressure, shuts down digestion

Parasympathetic system

prepares the body for the “rest and digest” response.

Ex: It lowers heart rate & blood pressure, reactivates digestion