Peripheral Nervous System

Area outside of CNS Consists of: – Nerves – Scattered ganglia

Nerve Structure Endoneurium – Encloses fibers Perineurium – Encloses fascicles of fibers Epineurium – Bundles fascicles – Outer covering

Functional Classification Mixed nerves – Carry impulses for both sensory and motor fibers Afferent nerves – Sensory – Carry impulses TO CNS Efferent nerves – Motor – Carry impulses FROM CNS

Cranial Nerves 12 pairs Head and neck region – Vagus nerves extend into thoracic and abdominal cavities Chart Page – Descriptions and functions

Spinal Nerves 31 pairs Named after region where it originates Each divides into dorsal and ventral rami – Contains both sensory and motor fibers Plexuses – Networks of nerves – Serve limbs

Autonomic Nervous System Motor subdivision Cardiac muscle, smooth muscle, gland regulation Also called “involuntary nervous system” Divided into two divisions – Sympathetic – Parasympathetic

Sympathetic Nervous Systems Prepares the body for stressful or emergency situations “fight or flight” Increases heart rate Make breathing easier Muscular strength is increased Norepinephrine has sympathetic (stimulating) effects

Parasympathetic Nervous System Controls body process during ordinary situations Conserves and restores Slows the heart rate Decreases blood pressure “Resting and digesting” Generally, acetylcholine has parasympathetic (inhibiting) effects