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The Nervous System

Terms in this set (54)

Central nervous system (CNS)
Nervous system subdivision that is composed of the brain and spinal cord.
Somatic nervous system
Subdivision of the PNS that controls voluntary activities such as the activation of skeletal muscles.
Peripheral nervous system (PNS)
Nervous system subdivision that is composed of the cranial nerves and spinal nerves.
Autonomic nervous system
Subdivision of the PNS that regulates the activity of the cardiac muscle, smooth muscle, and glands. It is also called the involuntary nervous system because it controls body activities automatically. It is very Important in maintaining homeostasis for the body.
Neuroglia
Cells that support, insulate, and protect neurons. These cells are able to divide and are usually involved in brain tumors.
Neurons
Cells that transmit electrical message from one area of the body to another area.
Axon
End of neuron that releases neurotransmitters away from the cell body.
Dendrite
End of neuron that conducts electrical currents toward the cell body.
Myelin
White, fatty material that covers long nerve fibers, protecting and insulating the fibers, as well as Increasing the speed of impulse transmission.
Cell body
Location of the nucleus in a neuron.
Schwann cells
Specialized cells that myelinate the fibers of neurons found in the PNS.
Synapse
Junction or point of close contact between neurons.
Tract
Bundle of nerve processes inside the CNS.
Nodes of Ranvier
Gaps in the myelin sheath between schwann cells.
Ganglia
Collection of nerve cell bodies found outside the CNS.
Efferent neuron
Neuron that conducts impulses away from the CNS to muscles and glands.
Stimuli
Changes, occurring within or outside the body, that affect nervous system functioning.
Afferent neuron
Neuron that conducts impulses toward the CNS from the body periphery.
Neurotransmitters
Chemicals released by neurons that stimulate other neurons, muscles, or glands.
Depolarization
State in which the polarity of the neuron is reversed as sodium ions rush into the neuron.
Polarized
Electrical condition of the plasma membrane of a resting neuron when it is inactive. Has fewer positive ions sitting on its inner face than on its outer face.
Repolarization
Period during which potassium ions diffuse out of the neuron resulting in a return of the polarization to its resting state. .
Potassium ions
The chief positive ion found inside a neuron during its resting state.
Sodium potassium pump
Process by which ATP is used to move sodium ions out of the cell and potassium ions back into the cell; completely restores the resting conditions of the neuron.
Hypothalamus
Site of regulation of water balance, body temperature, and metabolism.
Cerebellum
Responsible for the regulation of posture and coordination of skeletal muscle movements.
Thalamus
Important relay station for afferent fibers traveling to the sensory cortex for interpretation giving us a crude idea if the sensation we are about to feel will be pleasant or unpleasant.
Medulla oblongata
Found in the brain stem, contains autonomic centers which regulate blood pressure, heart rate, breathing, swallowing, and vomiting,
Concussion
Occurs when the brain injury is slight. Although patient may be dizzy or briefly lose consciousness, the damage is not permanent.
Contusion
Result of marked tissue destruction. If the cerebral cortex is damaged, the person may remain conscious but if the brain stem is damaged, may go into a permanent coma.
Coma
Total nonresponsiveness to stimulation.
Cerebral edema
After head injury, if bleeding occurs from ruptured vessels the brain may swell and left untreated, can result in death.
Stroke
Also called a cerebrovascular accident. Occurs when blood circulation to the brain area is blocked, as by a blood clot or a ruptured blood vessel and vital brain tissue dies. 3rd leading cause of death in the USA.
Alzheimers disease
Progressive degeneration of the brain that ultimately results in dementia.
Multiple sclerosis
Autoimmune disorder that attacks the proteins in the myelin sheath causing a short circuit of the nervous system resulting in person being unable to control muscle movement.
Sodium
Chief positive ion found outside of the neuron during its resting state.
Gyri
Elevated ridges of tissue in the cerebral hemispheres.
Sulci
Shallow grooves or furrows in the cerebral hemispheres.
Paired Cerebral Hemispheres
Most superior part of the brain, as well as the largest part of the brain.
Dienchephalon
Interbain that sits atop the brain stem and is enclosed by the cerebral hemispheres. Includes the thalamus and the hypothalamus.
Brain Stem
Provides a pathway for ascending and descending tracts and contains the midbrain, pons, and medulla oblongata.
Cerebellum
Large califlower-like structure that projects dorsally from under the cerebrum. Provides precise timing for skeletal muscle activity and controls balance and equilibrium.
Meninges
Consists of three protective tissues that surround the CNS: the dura mata, arachnoid mater, and the pia mata.
Meningitis
Inflammation of the meninges posing a serious threat if the bacteria or virus spreads to the CNS.
Cerebrospinal Fluid (CSF)
Watery broth similar in make up to blood plasma, but contains less protein and more vitamin C. Forms a watery cushion that protects fragile nervous tissue from blows and other trauma.
Hydrocephalus
"Water on the brain" Condition caused when something obstructs drainage of the cerebrospinal fluid causing it to accumulate and exert pressure on the brain. In newborn babies, it causes the head to enlarge as the brain increases in size.
Parkinson's Disease
Degeneration of the dopamine releasing neurons resulting in dopamine-deprived basal nuclei that then become over-active causing people to have persistent tremors, head nodding, forward bent walking posture, a shuffling gait, stiff facial expressions, and trouble initiating muscle movement.
Spinal Cord
Approximately about 17 inches long, this protrusion is an extension of the brain stem and extends all the way to just below the ribs. Contains 31 pairs of spinal nerves and is enlarged at the lumbar and cervical region where nerves to the arms and legs arise and leave the cord.
Spastic Paralysis
If the spinal cord is severed or crushed, the affected muscles stay healthy because they are stimulated by spinal reflex arcs but the movement become involuntary and the patient cannot feel anything below the damaged area.
Parasympathetic Division
Part of the autonomic nervous system that allows us to unwind and conserve energy. Also referred to as the resting and digesting system.
Sympathetic Division
Part of the autonomic nervous system that mobilizes the body during extreme situations. (fear, exercise, or rage)
Fight or Flight
Phrase given to instinctive response to danger where our heart rate, blood pressure, blood glucose levels, and oxygen intake from lungs increase to give one more energy for a response. Controlled by the sympathetic division.
Type A Personalities
People who work at breakneck speeds and push themselves continually due to excessive sympathetic nervous system disorder. Can lead to heart disease, high blood pressure, and ulcers.
Cerebral Palsy
Birth defect often due to a temporary lack of oxygen that causes brain damage and results in a poorly controlled voluntary muscles, seizures, mental retardation, and/or impaired hearing and eyesight.
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