Nervous System Flashcards
absence seizure
a small seizure in which there is a sudden or temporary loss of consciousness lasting only a few seconds
acetylcholine
a chemical substance in the body tissues that facilitates the transmission of nerve impulses from one nerve to another. It has a stimulant effect on some parts of the body and a depressant effect on other parts of the body; also known as a neurotransmitter.
afferent nerves
transmitters of nerve impulses toward the CNS; also known as sensory nerves
agnosia
loss of mental ability to understand sensory stimuli (such as sound, sight, touch) even though the sensory organs themselves are functioning properly
agraphia
the inability to convert one’s thoughts into writing
alexia
the inability to understand written words
analgesia
without sensitivity to pain
anesthesia
without feeling or sensation
aneurysm
a localized dilatation in the wall of an artery that expands with each pulsation of the artery; usually caused by hypertension or artherosclerosis
aphasia
inability to communicate through speech, writing or signs because of an injury or disease in certain areas of the brain.
apraxia
inability to perform coordinated movements or use objects properly; not associated with sensory or motor impairment or paralysis
arachnoid membrane
the weblike middle layer of the three membranous layers surrounding the brain and spinal cord.
astrocyte
a star-shaped neuroglial cell found in the the CNS
astrocytoma
a tumor of the brain or spinal cord composed of astrocytes
ataxia
without muscular coordination
aura
the sensation an individual experiences prior to the onset of migraine headache or an epileptic seizure. It may be a sensation of light or warmth and may precede the attack by hours or only a few seconds
autonomic nervous system
the part f the nervous system that regulates the involuntary vital functions of the body, such as the activities involving the heart muscle, smooth muscles, and the glands. Has two divisions: the SNS and the PNS.
axon
the part of the nerve cell that transports nerve impulses away from the nerve cell body
blood-brain barrier
a protective characteristic of the capillary walls o the brain that prevents the passage of harmful substances from the bloodstream into the brain tissue of CSF.
bradykinesia
Abnormally slow movement
brain stem
the stemlike portion of the brain that connects the cerebral hemisphere with the spinal cord. It contains the midbrain, the pons, and the medulla oblongata.
Brudzinski’s sign
a positive sign of meningitis, in which there is an involuntary flexion of the arm, hip and knee when the patient’s neck is passively flexed
burr hole
a hole drilled into the skull using a form of drill
cauda equina
the lower end of the spinal cord and the roots of the spinal nerves that occupy the spinal canal below the level of the first lumbar vertebra; so named because it resembles a horse’s tail
causalgia
a sensation of an acute burning pain along the path of a peripheral nerve, sometimes accompanied by erythema of the skin; due to injury to peripheral nerve fibers.
cell body
the part of the cell that contains the nucleus and the cytoplasm
central nervous system
one of the two main divisions of the nervous system, consisting of the brain and the spinal cord.
cephalagia
pain in the head; headache
cerebellum
the part of the brain responsible for coordinating voluntary muscular movement; located behind the brain stem.
cerebral concussion
a brief interruption of brain function, usually with a loss of consciousness lasting for a few seconds. This transient loss of consciousness is usually caused by blunt trauma (a blow to the head)
cerebral contusion
small scattered venous hemorrhages in the brain; better described as a “bruise” of the brain tissue occurring when the brain strikes the inner skull
cerebral cortex
the thin outer layer of nerve tissue, known as gray matter, that covers the surface of the cerebrum
cerebrospinal fluid
the fluid flowing through the brain and around the spinal cord that protects them from physical blow or impact.
cerebrum
the largest and uppermost part of the brain. It controls consciousness, memory, sensations, emotions and voluntary movements.
Cheyne-Stokes respirations
an abnormal pattern of breathing characterized by periods of apnea followed by deep rapid breathing
coma
a deep sleep in which the individual cannot be aroused and does not respond to external stimuli.
comatose
pertains to being in a coma
contracture
a permanent shortening of a muscle causing a joint to remain in an abnormally flexed position, with resultant physical deformity.
convolution
one of the many elevated folds of the surface of the cerebrum; also call gyrus.
craniotomy
a surgical incision into the cranium or skull
deficit
any deficiency or variation of the normal, as in weakness deficit resulting from a cerebrovascular accident (CVA)
dementia
a progressive irreversible mental disorder in which the person has deteriorating memory, judgment and ability to think
demyelination
destruction or removal of the myelin sheath that covers a nerve or nerve fiber.
dendrite
a projection that extends from the nerve cell body. It receives impulses and conducts them on the cell body.
diencephalon
the part of the brain located between the cerebrum and the midbrain. Its main structures consist of the thalamus, hypothalamus
diplopia
double vision; also called ambiopia
dura mater
the outermost of the three membranes (meninges) surrounding the brain and spinal cord
dyslexia
a condition characterized by an impairment of the ability to read. Letters and words are often reversed when reading.
dysphasia
difficult speech
efferent nerves
transmitters of nerve impulses away from the CNS; also known as motor nerves
embolism
an abnormal condition in which a blood clot (embolus) becomes lodged in a blood vessel, obstructing the flow of blood within the vessel.
epidural space
the space immediately outside the dura mater that contains a supporting cushion of fat and other connective tissues.
epilepsy
a neurological condition characterized by recurrent episodes of sudden brief attacks of seizures. The seizure may vary from mild and unnoticeable to full-scale convulsive seizures.
fissure
a deep groove on the surface of an organ
fontanelle or fontanel
a space covered by tough membrane between the bones of an infant’s cranium, called a “soft spot”.
gait
the style of walking
ganglion
a knotlike mass of nerve tissue found outside the brain or spinal cord (plural: ganglia)
gray matter
the part of the nervous system consisting of axons that are not convered with myelin sheath, giving a gray appearance.
gyrus
one of the many elevated folds of the surface of the cerebrum (plural: gyri).
hemiparesis
slight or partial paralysis of one half of the body
hemiplegia
paralysis of one half of the boy
herpes zoster
an acute infection caused by the same virus that causes chickenpox, characterized by painful vesicular lesions along the path of a spinal nerve; also called shingles
hyperesthesia
excessive sensitivity to sensory stimuli, such as pain or touch
hyperkinesis
excessive muscular movement and physical activity; hyperactivity.
hypothalamus
a part of the brain located below the thalamus that controls many functions, such as body temperature, sleep and appetite.
interneurons
connecting neurons that conduct impulses from afferent nerves to or toward motor nerves
kernig’s sign
a diagnostic sign for meningitis marked by the person’s inability to extend the leg completely when the thigh is flexed upon the abdomen and the person is sitting or lying down.
kinesiology
the study of muscle movement
lethargy
a state of being sluggish
longitudinal fissure
a deep groove in the middle of the cerebrum that divides the cerebrum into the right and left hemisphere.
medulla oblongata
one of the three parts of the brain stem. It is the most essential part f the brain in that it contains the cardiac, vasomotor, and respiratory centers in the brain.
meninges
the three layers of protective membranes that surround the brain and spinal cord.
microglia
small neuroglial cells found in the interstitial tissue of the nervous system that engulf cellular debris, waste products, and pathogens withing the nerve tissue.
midbrain
the uppermost part of the brain stem.
motor nerves
Transmitters of nerve impulses away from the CNS; also known as efferent nerves
myelin sheath
a protective sheath that covers the axons of many nerves in the body. It acts as an electrical insulator and helps to speed the conduction of nerve impulses.
narcolepsy
a rare syndrome of uncontrolled, sudden attacks of sleep.
nerve
a cordlike bundle of nerve fibers that transmit impulses to and from the brain and spinal cord to other parts of the body. It is macroscopic.
nerve block
the injection of a local anesthetic along the course of a nerve or nerves to eliminate sensation to the area supplied by the nerve(s); also called conduction anesthesia.
neuralgia
Severe, sharp, spasmlike pain that extends along the course of one or more nerves.
neuritis
Inflammation of a nerve
neuroglia
the supporting tissue of the nervous system
neurologist
a physician who specializes in treating the diseases and disorders of the nervous system.
neurology
the study of the nervous system and its disorders
neuron
a nerve cell
neurosurgeon
a physician who specializes in surgery of the nervous system.
neurosurgery
any surgery involving the nervous system (i.e., of the brain, spinal cord, or peripheral nerves).
neurotransmitter
a chemical substance within the body that activates or inhibits the transmission of nerve impulses at synapses.
nuchal rigidity
rigidity of the neck. The neck is resistant to flexion. This condition is seen with patients with meningitis
occlusion
blockage