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Nervous System
A&P II Chapter 8
Term | Definition |
---|---|
Neuroglia | connective tissue for nervous system - provides support system for neurons - does not conduct impulses - protect nervous system through phagocytosis |
three types of neuroglia cells | astrocytes, microglia, oligodendrocytes |
phagocytosis | engulfing bacteria of other microorganisms |
astrocytes | star-shaped cells - largest & most numerous - found only in CNS - forms blood-brain barrier |
neuron | functional unit of nerve cell - three basic parts are cell body, axon, dendrites |
cell body (of neuron) | contains nucleus and cytoplasm |
axon | carries impulses away from cell body - some are covered with myelin sheath |
dendrites | conduct impulses toward cell body |
synapse | space between two nerves - contains neurotransmitters |
myelin sheath | protects axon and speeds transmission of impulses - acts like insulator - appears white making up white matter |
brain and spinal chord | part of CNS - surrounded by meninges (membranes) and cerebrospinal fluid (CSF) |
sympathetic nerves | "fight or flight" regulate essential involuntary body functions - increased heart rate, blood pressure, constrict blood vessels |
parasympathetic nerves | regulate essential involuntary body functions bringing body to restful state |
autonomic nervous system | provides involuntary control - contains sympathetic and parasympathetic nerves |
divisions of nervous system | central nervous system (CNS) contains brain and spinal chord & peripheral nervous system (PNS) contains 12 pairs of cranial nerves and 31 pairs of spinal nerves |
peripheral nervous system (PNS) | somatic nervous system and autonomic nervous system |
apraxia | inability to perform coordinated movements or use objects properly - NOT associated with sensory or motor impairment or paralysis |
ataxia | without muscular coordination |
agraphia | inability to convert one's thoughts into writing |
aphasia | inability to communicate through speech, writing, or signs bc of an injury to or disease in certain areas of the brain |
cerebral concussion | brief interruption of brain function, usually with loss of consciousness lasting for a few seconds. usually caused by blunt trauma to the head |
cerebral contusions | small scattered venous hemorrhages in the brain - "bruise" of the brain tissue occurring when brain strikes inner skull |
Bell's palsy | temporary or permanent unilateral weakness or paralysis of the muscles in the face |
epilepsy | syndrome of recurring episodes of excessive irregular electrical activity of the brain resulting in involuntary muscle movements called seizures |
hemiplagia | partial paralysis of one half of the body |
paraplegia | paralysis of lower extremities and trunk due to spinal chord injuries |
quadriplegia | paralysis of all four extremities and trunk of body cause by injury to spine at cervical vertebrae |
cerebrovascular accident (CVA) | involves death of a specific portion of brain tissue resulting from a decrease in blood flow (ischemia) to that area of brain aka stroke |
causes of CVA or stroke | cerebral hemorrhage, thrombosis and embolism |
encephalitis | inflammation of the brain cause by a virus that enter the CNS - measles, mumps or mosquito or tick bite |
meningitis (acute bacterial) | serious bacterial infection of meninges which covers the brain and spinal chord - can be treated with antibiotic therapy |
Parkinson's disease | degenerative, slowly progressive deterioration of nerves in the brain stem's motor system. systems are motor dysfunction, autonomic system dysfunction, mental and emotional dysfunction. occurs in late 30's/40's |
thrombosis | clots in arteries |
embolus | detached clot in circulatory system |
cerebral hemorrorhage | due to hypertension |
grand mal seizure | epileptic seizure characterized by sudden loss of consciousness and involuntary muscular contraction, proceeded by aura (flashing lights), vacillates between rigid body and alternating contracting and relaxing of muscles. aka tonic-clonic seizure |
petit mal seizure | aka absence seizures - last only a few seconds - sudden temporary loss of consciousness |
cephalagia | headache |
multiple sclerosis (MS) | degenerative inflammatory disease of the CNS attacking the myelin sheath of spinal chord and brain |