Term
| central nervous system (CNS) |
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Definition
brain and spinal cord enclosed in bony coverings
enclosed by cranium and vertebral column |
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Term
| peripheral nervous system (PNS) |
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Definition
all the nervous system except the brain and spinal cord
composed of nerves and ganglia
nerve – a bundle of nerve fibers (axons) wrapped in fibrous connective tissue
ganglion – a knot-like swelling in a nerve where neuron cell bodies are concentrated |
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Definition
| carries signals from receptors in the skin, muscles, bones, and joints |
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Definition
| the control center of the neuron |
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Definition
| movement down the axon away from soma |
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Definition
| movement up the axon toward the soma |
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Term
| Six Types of Neuroglial Cells |
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Definition
four types occur only in CNS
oligodendrocytes,ependymal cells,microglia,astrocytes
two types occur only in PNS
Schwann cells,satellite cells |
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Term
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Definition
form myelin sheaths in CNS
each arm-like process wraps around a nerve fiber forming an insulating layer that speeds up signal conduction |
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Term
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Definition
lines internal cavities of the brain
cuboidal epithelium with cilia on apical surface
secretes and circulates cerebrospinal fluid (CSF)
-clear liquid that bathes the CNS |
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Definition
small, wandering macrophages formed white blood cell called monocytes
thought to perform a complete checkup on the brain tissue several times a day
wander in search of cellular debris to phagocytize |
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Definition
most abundant glial cell in CNS
cover entire brain surface and most nonsynaptic regions of the neurons in the gray matter of the CNS
diverse functions |
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Definition
envelope nerve fibers in PNS
wind repeatedly around a nerve fiber
produces a myelin sheath similar to the ones produced by oligodendrocytes in CNS
assist in the regeneration of damaged fibers |
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Definition
surround the neurosomas in ganglia of the PNS
provide electrical insulation around the soma
regulate the chemical environment of the neurons |
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Definition
masses of rapidly dividing cells
mature neurons have little or no capacity for mitosis and seldom form tumors |
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Definition
| meninges (protective membranes of CNS) |
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Term
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Definition
three connective tissue membranes that envelop the brain
lies between the nervous tissue and bone
as in spinal cord, they are the dura mater, arachnoid mater, and the pia mater
protect the brain and provide structural framework for its arteries and veins |
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Term
| 31 pairs of spinal nerves (mixed nerves) |
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Definition
8 cervical (C1 – C8) C1 between skull and atlas
-others exiting at intervertebral foramen
12 thoracic (T1 – T12)
5 lumbar (L1 – L5)
5 sacral (S1 – S5)
1 coccygeal (Co) |
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Term
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Definition
extend through the arachnoid to the dura
anchors spinal cord to limit side to side movement |
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Term
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Definition
| thought brain was ‘radiator’ to cool blood |
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Term
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Definition
occupies posterior cranial fossa
marked by gyri, sulci, and fissures
about 10% of brain volume
contains over 50% of brain neurons |
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Term
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Definition
-in cranial cavity - 2 layers
outer periosteal – equivalent to periosteum of cranial bones
inner meningeal – continues into vertebral canal and forms dural sac around spinal cord
-cranial dura mater is pressed closely against cranial bones
no epidural space
not attached to bone except: around foramen magnum, sella turcica, the crista galli, and sutures of the skull
layers separated by dural sinuses – collect blood circulating through brain
-folds inward to extend between parts of the brain
falx cerebri separates the two cerebral hemispheres
tentorium cerebelli separates cerebrum from cerebellum
falx cerebelli separates the right and left halves of cerebellum |
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Term
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Definition
inflammation of the meninges
serious disease of infancy & childhood
especially between 3 months and 2 years of age
signs include high fever, stiff neck, drowsiness, and intense headache and may progress to coma – death within hours of onset |
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Term
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Definition
cause swelling the brain, enlarging the ventricles, and hemorrhage
lumbar puncture (spinal tap) draws fluid from subarachnoid space between two lumbar vertebrae |
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Definition
allows brain to attain considerable size without being impaired by its own weight
if it rested heavily on floor of cranium, the pressure would kill the nervous tissue |
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Definition
protects the brain from striking the cranium when the head is jolted
shaken child syndrome and concussions do occur from severe jolting |
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Definition
| flow of CSF rinses away metabolic wastes from nervous tissue and homeostatically regulates its chemical environment |
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Definition
| deep groove that separates cerebral hemispheres |
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Term
| nerves of peripheral nervous system are ensheathed in Schwann cells |
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Definition
forms neurilemma and often a myelin sheath around the axon
external to neurilemma, each fiber is surrounded by basal lamina and then a thin sleeve of loose connective tissue – endoneurium
fascicles – nerve fibers gathered in bundles
perineurium – wraps fascicles
composed of up to 20 layers of overlapping, squamous ,
epithelium-like cells
epineurium – bundles numerous fascicles that constitutes whole nerve
composed of dense irregular connective tissue
protects nerve from stretching and injury |
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Term
| visceral sensory division |
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Definition
carries signals from the viscera of the thoracic and abdominal cavities
heart, lungs, stomach, and urinary bladder |
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