Section 7.3

1. Lies outside the CNS 2. Composed of the peripheral nerves and ganglia 3. Nerves- bundles of myelinated axons 4. Ganglia- are the swellings associated with nerves that contain collections of cell bodies 5. Divided into the somatic system and autonomic system 6. Somatic system- serves the skin, skeletal muscles, and tendons. 7. Autonomic system- regulates the activity of the cardiac muscles, smooth, muscles, and glands (there are exceptions.

1. Endoneurium surrounds each fiber 2. Groups of fibers are bound into fascicles by perineurium 3. Fascicles are bound together by epineurium

1. Are attached to the brain pairs 3. Collection of both sensory and motor neurons 4. Control head, neck, and facial regions 5. Most belong to the autonomic system 6. Exception: Vagus Nerve, which has branches to most of the internal organs and is part of the autonomic system

1. 31 pairs, one at the level of each vertebrae 2. Carry fibers that belong to either the somatic or autonomic system 3. Mixed nerves, containing both sensory & motor fibers 4. Anterior root= motor 5. Posterior root= sensory

1. Many actions are voluntary, originating in the cerebral cortex 2. Other actions are due to reflexes, which are involuntary responses to stimuli 3. Cranial reflexes- involve the brain; ex- we automatically blink our eyes

1. Involuntary branch of the nervous system 2. (2) Divisions: Sympathetic and Parasympathetic 3. Both divisions have several features in common: a. They function automatically b. They innervate all organs c. They utilize 2 motor neurons and 1 ganglion for each impulse

Sympathetic 1. Involuntary 2. Preganglionic fiber is shorter than the postganglionic fiber 3. Motor fibers are located in the thoracic and lumbar regions 4. Norepinephrine= neurotransmitter 5. Effects smooth muscle, cardiac muscle, and glands 1. Involuntary 2. Preganglionic fiber is longer than the postganglionic fiber 3. Motor fibers are located in the cranial and sacral regions 4. Acetylcholine= neurotransmitter 5. Effects smooth muscle, cardiac muscle, and glands Parasympathetic

Sympathetic 1. Important during the “fight or flight” response to an emergency situation 2. Takes over and causes an increase in all activities: heartbeat, breathing, energy 3. Inhibits the digestive tract 1. Referred to as the “housekeeper” division 2. Maintains daily necessary functions 3. Promotes digestion, slows down the heartbeat 4. Keeps us in a relaxed state Parasympathetic