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Nervous system
Structure & Function
Term | Definition |
---|---|
Nerve cell, Neuron | |
cell body | Part of a nerve cell that has branches or fibers that reach out to send or receive impulses. |
dendrite | A thin branching extension of a nerve cell that conducts nerve impulses toward the cell body. |
axon | Part of a nerve cell that conducts nerve impulses away from the cell body. |
myelin sheath | Fatty tissue that covers axons. |
terminal end fibers | Group of fibers at the end of an axon that passes the impulses leaving the neuron to the next neuron. |
synapse | Space over which nerve impulses jump from one neuron to another. |
neurotransmitters | Various substances located in tiny sacs at the end of the axon. |
excitability | Ability to respond to stimuli. |
stimulus | Anything that arouses a response. |
conductivity | Ability to transmit a signal. |
efferent (motor) neuron | Neuron that carries information to the muscles and glands from the central nervous system. |
afferent (sensory) neuron: | Neuron that carries information from the sensory receptors to the central nervous system. |
Interneuron | Neuron that carries and processes sensory information. |
nerves | Bundle of neurons that bear electrical messages to the organs and muscles of the body. |
acetylcholine | Chemical that stimulates cells. |
noreplnerphrine | Hormone produced in response to stress. |
nerve impulse | Released energy that is received or transmitted by tissue or organs and that usually provokes a response. |
receptors | Tissue or organ that receives nerve impulses; part of a target cell with properties compatible with a particular substance (hormone). |
neurillema | membranous covering of myelin sheath |
blood brain barrier | barrier that permits a few chemicals to reach brains neurons but blocks most |
central nervous system | The brain and spinal cord. |
brain | Body organ responsible for controlling the body’s functions and interactions with outside stimuli. |
brain stem | One of the four major divisions of the brain; division that controls certain heart, lung, and visual functions. |
midbrain | Part of the brainstem involved with visual reflexes. |
pons | Part of the brainstem that controls certain respiratory functions. |
medulla oblongata | Part of the brainstem that regulates heart and lung functions, swallowing, vomiting, coughing, and sneezing. |
cerebellum | One of the four major divisions of the brain; division that coordinates musculoskeletal movement. |
cerebrum | One of the four major divisions of the brain; division involved with emotions, memory, conscious thought, moral behavior, sensory interpretations, and certain bodily movement. |
cerebral cortex | Outer portion of the cerebrum. |
fissure | Deep slit in the skin; deep furrow or slit (as in bone); one of many indentations of the cerebrum; sulcus |
convolutions | Folds in the cerebral cortex; gyri. |
basil ganglia | Large masses of gray matter within the cerebrum. |
frontal lobe | controls voluntary motor movements, emotions, behaviors |
parietal lobe | controls and interprets sense and taste |
temporal lobe | controls memory, equilibrium, emotion and hearing |
occipital lobe | controls vision and form of expression |
corpus callosum | Bridge of nerve fibers that connects the two hemispheres of the cerebrum. |
diencephalon | One of the four major structures of the brain; it is the deep portion of the brain and contains the thalamus. |
thalamus | serves as a sensory relay station. |
hypothalamus | serves as a sensory relay station; gland in the nervous system that releases hormones to aid in regulating pituitary hormones. |
epithalamus, ventral thalamus | serves as a sensory relay station. |
cranium | Bony structure that the brain sits in. |
cerebral spinal fluid | Watery fluid that flows throughout the brain and around the spinal cord |
ventricle | 1. Either of the two lower chambers of the heart. 2. Cavity in the brain for cerebrospinal fluid. |
spinal cord | extends down from the occipital bone (medulla oblongata) to the space between the first and second lumbar vertebrae |
meninges | Three layers of membranes that cover and protect the brain and spinal cord. |
dura mater | Three layers of membranes that cover and protect the brain and spinal cord. |
arachnoid | Middle layer of meninges. |
subdural space | Area between the dura mater and the pia mater across which the arachnoid runs. |
pia mater | Innermost layer of meninges |
epidural space | Area between the pia mater and the bones of the spinal cord. |
olfactory (sensory) | sense of smell |
optic (sensory) | sense of vision |
oculomotor (motor) | involves movement of eyes, controlling both exterior and interior of parts of the eye |
trochlear (motor) | muscles that move the eye |
trigeminal (sensory and motor) | eyes, tear glands, scalp, forehead, teeth, gums, lips and mouth ,muscles |
abducens (motor) | muscle conditioning |
facial (sensory and motor) | taste, facial expressions, tear and salivary glands |
vestibulocochlear (sensory) | equilibrium and hearing |
glossopharyngeal (sensory and motor) | pharynx, tonsils, tongue, carotid artery, stimulates salivary glands |
vagus (sensory and motor) | speech, swallowing, heart muscles and certain glands |
accessory (cranial and spinal- motor) | muscles of soft palate, pharynx, larynx, neck and back |
hypoglossal (motor) | muscles that move the tongue |
cervical (neck) | muscles of the back of the head, neck and in the diaphragm |
brachial (lower neck, axila) | muscles of the skin of the neck, shoulders, arm and hand |
lumbar (posterior ab wall) | abdominal skin and muscles |
sacral (posterior pelvis wall) | muscles off the butt, thighs, feet, legs and voluntary sphincters |
coccygeal (coccyx and surrounding area) | skin in coccyx region |
cervical nerves | C1-C8 |
thoracic nerves | T1-T12 |
Lumbar nerves (cauda equina) | L1-L5 |
Sacral nerves | S1-S5 |
Coccygeal nerve | Co |
parasympathetic nervous system | Part of the autonomic nervous system that operates when the body is in a normal state. |
sympathetic nervous system | Part of the autonomic nervous system that operates when the body is under stress. |
cranial nerves | Any of 12 pairs of nerves that carry impulses to and from the brain. |
spinal nerves | Any of 31 pairs of nerves that carry messages to and from the spinal cord and the torso and extremities. |
somatic nervous system | Part of the peripheral nervous system that receives and processes sensory input from various parts of the body. |
autonomic nervous system | Part of the peripheral nervous system that carries impulses from the central nervous system to glands, smooth muscles, cardiac muscle, and various membranes. |