a & p chpt 9

the brain and spinal cord

made up of all the nerves outside of the CNS

any tissue or organ that carries out a nervous command (muscles and glands)

nervous system that is voluntarily controlled, (by conscious will) -- its effectors are the skeletal muscles

the involuntary system that controls smooth muscle, cardiac muscle, and glands

fatty material that covers some axons and insulates and protects them

spaces in between the schwann cells

nuerons that conduct impulses to the spinal cord and brain

carry messages away from the CNS

relay information within the CNS

a fiber bundle in the PNS

a fiber bundle in the CNS

groupings of individual fibers

layer around an individual fiber

layer around a fascicle

layer around the whole nerve

• cells that support and protect the neurons
• protect and nourish nervous tissue
• support nervous tissue and bind it to other structures
• aid in repair of cells
• act as phagocytes
• regulate the composition of fluids around and between cells

the point of junction for transmitting the nerve impulse

• chemicals used to trigger an acton potentialacross a synaptic cleft
• slower than electrical transmission

sensory impulses that enter the spinal cord and are transmitted toward the brain

motor impulses traveleing from the brain and to the peripheral system

a complete pathway thru the nervous sytem from stimulus to response

a rapid and uncomplicated and automatic response involving very few nuerons

a simple reflex that passes thru the spinal cord alone and does not involve the brain

a disease in which the myelin sheath around axons is damaged and the nueron fibers themselves degenerate

a nervous system disorder in which motor neurons are destroyed

a viral disease that multplies in the spinal cord's motor neurons, leading to paralysis

afferent (sensory) neurons

efferent (motor) neurons

the larger anterior branches of spinal nerves that interlace to form networks

• cervical plexus
• brachial plexus
• lumbarsacral plexus

allow us to map the skin of the human body using the spinal nerves

• increase in heart rate and force of heart contractions
• increase in blood pressure
• dilation of blood vessels to skeletal muscles
• dilation of bronchial tubes
• stimulation of the central part of the adrenal gland
• increase in basal metabolic rate
• dilation of pupil and decrease in focusing ability for near objects