Peripheral Nervous System: Parasympathetic v.s. Sympathetic

Body organs served by Autonomic NS receive both

Parasympathetic and Sympathetic fibers

• Exceptions:

most blood vessels, structures of the skin, some glands, and adrenal medulla only have sympathetic fibers.

• When both divisions serve an organ, they have antagonistic (opposite) effects

Because their postganglionic fibers release different neurotransmitters

Sympathetic and Parasympathetic Postganglionic Fibers release

different neurotransmitters

• Parasympathetic are called cholinergic fibers

Release acetylcholine

• Sympathetic are called adrenergic fibers

Release norepinephrine

PreGanglionic Axons of BOTH release

acetylcholine

Sympathetic NS

Activated when we are scared, or physically stressed.

Effects last a few min until hormones are destroyed by liver

Parasympathetic: Primary Goals

• Normal digestion

• Elimination of waste

• Conserve body energy

Afferent Nerves

• Sensory Nerves

• Receive Information

• Transmit sensory information gathered from the skin, muscles, and joints to the CNS

Efferent Nerves

• Motor Nerves

• Send information on

• Carries information from the CNS out to the muscles and glands