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Central Nervous System Vocab
Ch. 12 & Ch. 11
56
Physiology
Undergraduate 1
11/30/2008

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Term
neuroglia (glial cells)
Definition
Smaller and much more numerous than neurons; functions include physical support, circulation, protection from microbes & toxins, nourishment, and maintenance of proper chemical environment for nerve activity.
Term
supporting cells
Definition
One of two types of cells in the CNS. They are the smaller cells that wrap the delicate neurons.
Term
Schwann cells
Definition
A PNS glial cell that surrounds one neuron fiber to form myelin sheaths. They are vital for the regeneration of damaged fibers.
Term
neurofibrils
Definition
Bundles of intermediate filaments that maintain cell shape and form a network throughout the cell body.
Term
neurilemma
Definition
The portion of the Schwann cell that forms a bulge from the nucleus and cytoplasm.
Term
gray matter
Definition
Found in regions of the brain and spinal cord where there is unmyelinated fibers and (mostly) cell bodies.
Term
white matter
Definition
Regions of the brain and spinal cord containing dense collections of myelinated nerve fibers.
Term
interneurons
Definition
Multipolar neurons making up 99% of the neurons in the body and are confined to the CNS. They lie between motor/sensory neurons in neural pathways and shuttle signals through CNS pathways where integration occurs.
Term
voltage
Definition
The measure of potential energy generated by separated charge.
Term
chemically (ligand) gated channels
Definition
Open when the appropriate chemical binds.
Term
voltage-gated channels
Definition
Open/close in response to changes in membrane potential.
Term
leakage (non-gated) channels
Definition
Are always open.
Term
hyperpolarization
Definition
Increase in membrane potential; the inside of the membrane becomes MORE negative.
Term
depolarization
Definition
Reduction in membrane potential; the inside of the membrane becomes LESS negative.
Term
pyramidal cells
Definition
Neurons of the CNS controlling the voluntary movements of skeletal muscles. 85% of the cells forming the pyramidal tracts are from the primary motor cortex and the other 15% from the premotor cortex.
Term
diencephalon
Definition
Forms the central core of the forebrain enclosing the third ventricle. Includes the thalamus, hypothalamus & epithalamus.
Term
thalamus
Definition
Serves as the gateway to the cerebral cortex by mediating sensation, motor activities, cortical arousal, learning & memory. All afferent impulses converge at the thalamus.
Term
hypothalamus
Definition
Located below (hypo) the thalamus. It is the body's main visceral control center and vitally important for homeostasis. It regulates ANS activity (influencing blood pressure, heartbeat, pupil size, digestive tract mobility); involved in the perception of fear, pleasure, rage; serves as the body's thermostat; regulates feelings of hunger, water balance, thirst; & controls functioning of the endocrine system.
Term
epithalamus
Definition
Most dorsal portion of the diencephalon.
Term
pineal body
Definition
Secretes the hormone melatonin.
Term
pons
Definition
Composed of conduction tracts and issues several cranial nerve pairs. Pathway for "conversations" between the motor cortex and cerebellum.
Term
medulla
Definition
Crucial ANS reflex center that receives instructions via the hypothalamus to medullary reticular centers which carry them out. Examples: adjusting force of heart rate to meet bodies needs, changing blood vessel diameter, controlling the rate/depth of breathing.
Term
cerebellum
Definition
Subconsciously provides the precise timing and appropriate patterns of skeletal muscle contraction for smooth, coordinated movement. Several types of neurons are found here including Purkinje cells.
Term
cerebellar peduncles
Definition
Three paired fiber tracts connecting the cerebellum to the brain stem.
Term
Purkinje cells
Definition
Only cortical neuron that sends axons through white matter to synapse with the central nuclei of the cerebellum.
Term
limbic system
Definition
Group of structures forming our emotional brain. Interacts with the prefrontal lobes resulting in an intimate relationship between our feelings and thoughts (cognitive brain). This further results in 1. reacting emotionally to things we consciously understand to be happening and 2. causes awareness of the emotional richness of our lives.
Term
reticular formation
Definition
Loosely clustered neurons forming three broad columns extending the length of the brain stem. Provides a continuous stream of impulses to the cerebral cortex keeping it alert and enhances excitability. Also acts as a filter for sensory inputs (combined with the cerebral cortex, 99% of all sensory stimuli are unimportant and filtered out). Example: watch on wrist.
Term
commissural tracts
Definition
Bundled myelinated fibers located in white matter that run horizontally connecting corresponding gray areas of the hemispheres. Examples: corpus callosum, anterior & posterior commissures.
Term
association tracts
Definition
Bundled myelinated fibers located in white matter that run horizontally connecting different parts of the SAME hemisphere.
Term
projection tracts
Definition
Bundled myelinated fibers located in white matter that run vertically. Examples: axons entering cerebrum from lower brain/spinal cord or axons leaving cerebrum.
Term
primary motor cortex
Definition
Located in the PRECENTRAL GYRUS. Contains pyramidal cells allowing us to consciously control the precise voluntary movements of our skeletal muscles.
Term
premotor cortex
Definition
Area of brain in front of primary motor cortex (precentral gyrus) that serves as the staging area for motor functions. Movements are organized here before being executed and with repetition the pattern is stored in the memory.
Term
Broca's aphasia
Definition
Damage to Broca's area will cause this speech problem where speech is slow and poorly articulated. However, control over lips, larynx, tongue and speech comprehension is unaffected.
Term
brain waves
Definition
Patterns of neuronal electrical activity generated by synaptic activity at the surface of the cortex rather than by action potentials in white matter.
Term
olfactory nerve (I)
Definition
Sensory (smell).
Term
optic nerve (II)
Definition
Sensory (vision).
Term
oculomotor (III)
Definition
Motor ("eye mover") & contains parasympathetic fibers that serve visceral muscles and glands.
Term
trochlear (IV)
Definition
Motor ("eye pulley").
Term
trigeminal (V)
Definition
Sensory (general sensation) & Motor (facial sensory fibers & chewing muscles).
Term
abducens (VI)
Definition
Motor (eye abduction).
Term
facial (VII)
Definition
Sensory (taste), Motor (muscles for facial expression), contains parasympathetic fibers that serve visceral muscles and glands.
Term
vestibulocochlear (VIII)
Definition
Sensory (hearing & balance).
Term
glossopharyngeal (IX)
Definition
Sensory (taste), Motor (moves tongue and pharynx).
Term
vagus (X)
Definition
Sensory (taste), Motor (only nerve to extend beyond the neck)
Term
accessory (XI)
Definition
Motor (an accessory to the vagus nerve)
Term
hypoglossal (XII)
Definition
Motor (controls some tongue-moving muscles)
Term
What is the order of the cranial nerves from I-XII?
Definition
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
Term
visual association area
Definition
Interprets visual stimuli enabling us to recognize what we our seeing.
Term
auditory association area
Definition
Sound perception occurs and memories of sounds are stored here.
Term
primary auditory cortex
Definition
Sound impulses are transmitted here and then interpreted as pitch, loudness, and location.
Term
primary visual cortex
Definition
Receives visual information that originates on the retina of the eye.
Term
anterior association area (prefrontal cortex)
Definition
Most complicated cortical region involved with intellect, complex learning abilities, recall, and personality.
Term
posterior association area
Definition
Large area of the brain involved in recognizing patterns and faces, localizing us and our surroundings in space, and binding different sensory inputs into a coherent whole. Also many parts are involved in understanding written and spoken language.
Term
limbic association area
Definition
Provides the emotional impact which makes a scene important to us.
Term
brain stem (includes?)
Definition
Midbrain, pons, medulla oblongata. Accounts for only 2.5% of brain mass.
Term
choroid plexuses
Definition
Hang from the roof of each ventricle and forms cerebrospinal fluid.
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