Nervous system #3 Flashcards
Axon
(ak-son) A single elongated projection from a nerve cell body that transmits impulses away from the cell body.
Brain
The Largest and most complex unit of the nervous system; the brain is responsible for perception, sensation, emotion, intellect, and action.
Central Nervous System
(CNS) The brain and spinal cord and their coverings.
Cerebrospinal Fluid
(CSF) a clear, colorless fluid that flows throughout the brain and around the spinal cord, cushioning and protecting these structures and maintaining proper pH balance.
Gray Matter
Unmyelinated nervous tissue in the central nervous system.
Myelin
A white, fatty insulating substance formed by the Schwann cell that surrounds some axons. Also produced in the central nervous system by oligodendrocytes.
Neuroglia
Specialized connective tissue cells that support, protect, and hold neurons together and maintain homeostasis in the nervous system.
Neurons
Nerve cells the conduct impulses.
Synapses
A space between neurons or between a neuron and an effector organ.
Cerebellum
The second largest part of the brain; the cerebellum is involved with balance, posture, coordination, and movement.
Cerebrum
The Largest of the brain division; the cerebrum consists of two hemispheres that occupy the uppermost region of the cranium. The cerebrum receives, interprets, and associates incoming information with past memories and then transmits the appropriate motor response.
Dendrites
Branching projections from the nerve cell body that carry signals to the cell body.
Dorsal root
Also called the posterior root. Prosterior attachment of a spinal nerve to the spinal cord. Transmits sensory information into the spinal cord.
Neurolemma
Also called Schwann membrane, sheath of Schwann, and endoneural membrane. The outer cell membrane of Schwann cell that encloses the myelin sheath found on certain peripheral nerves. Essential in regeneration of injured axons.
Neurotransmitters
Chemical compounds that generate action potentials when released into the synapses from presynaptic cell.
Schwann cell
A specialized cell that forms myelin.
Spinal cord
The portion of the central nervous system that exists the skull and extends into the vertebral column. The two major functions of the spinal cord are to conduct nerve impulses and to be a center for spinal reflexes.
White matter
Myelinated nerve tissue in the center nervous system.
Dermatome
A cutaneous (skin) section supplied by a single spinal nerve.
Efferent nerves
Motor nerves that transmit motor impulses; they link the central nervous system to the effectors outside it.
Myotome
A skeletal muscle or group of skeletal muscles that receives motor axons from a particular spinal nerve.
Plexus
A network of intertwining nerves that innervates a particular region of the body.
Mixed nerves
Nerves that contain sensory and motor axons.
Cranial Nerves
Twelve pairs of nerves that originate from the olfactory bulbs, thalamus, visual cortex, and brainstem. They transmit information to and from the sensory organs of the face and the muscles of the face, neck, and upper shoulders, as well as organs of the thorax and abdomen.
Sympathetic nervous system
The part of the autonomic nervous system that provides for most of the active function of the body; when the body is under stress, the sympathetic nervous system predominantes with fight - flight responses.
Thermal receptors
Sensory receptors that detect changes in temperature.
Proprioceptors
Sensory receptors that provide the body with information about position, movement, muscle tension, joint activity, and equilibrium.
Spinal nerves
Thirty-one pairs of mixed nerves, originating in the spinal cord and emerging from the vertebral column; they are part of the peripheral nervous system.
Somatic nervous system
A system of nerves that keeps the body in balance with external environment by trasmitting impulses among the central nervous system, skeletal muscles, and skin.
Reflex
An automatic, involuntary reaction to a stimulus.
Free nerve endings
Sensory receptors that detect itch and tickle sensations.
Parasympathetic nervous system
The energy conservation and restorative system associated with what commonly is called the relaxation response.
Brainstem
The inferior, primitive portion of the brain that contains centers for vital function and reflex actions, such as vomiting, coughing, sneezing, posture, and basic movement patterns.
Ascending tracts
Tracts in the spinal cord that carry sensory information to the brain.
