In addition to the
definitions below, see also the earlier study guide, the summary on
pages 236-237, the chart of
brain divisions, the illustrations on pages 209, 210, 211,
and the summary chart and
illustrations of cranial nerves on pages 223-225.
Refractory
period - time interval when a neuron cannot fire at all (absolute
refractory period), or can fire only if the stimulus is sufficiently larger
than normal (relative refractory period).
Sympathetic nervous system - division of the autonomic nervous system that stimulates increased heartbeat and other “fight or flight” responses
Parasympathetic nervous system - divison of the autonomic nervous system that lowers heartbeat and stimulates “rest and rumunate” responses
Anterior, posterior, & lateral columns - columns of white matter within the spinal cord (ascending & descending tracts)
Cerebral cortex - surface layer of gray matter in the cerebral hemispheres, responsible for most conscious activity and rational thought
Homunculus -
diagram showing distorted body in proportion to representation in the cerebral
cortex
Archipallium - former dorsal portion of cerebral cortex (now tucked in medially), incl. hippocampus
Hippocampus - folded portion of archipallium responsible for memory consilidation
Paleopallium - part of cerebral cortex concerned with emotions and smells, esp. in lower mammals
Neopallium - part of cerebral cortex concerned with vision and rational problem-solving, esp. in primates
Corpus callosum - large area (commissure) of nerve tracts crossing bet. right & left cerebral hemispheres
Basal nuclei - areas of gray matter deep inside cerebrum, near lateral ventricles
Concussion - a blow to the head, affecting the brain but not crushing it
Contusion - a blow to the head in which part of the brain is crushed
Cerebrovascular accident (CVA, “stroke”) - death of part of the brain due to impairment of blood supply
Parkinsonism - deficit of dopamine in certain basal nuclei; symptoms include difficulty initiating voluntary movements
Huntington’s disease - hereditary excess of dopamine in certain basal nuclei, leading to some uncontrolled movements & eventually death
Alzheimer’s disease - loss of memory and other brain functions due to buildup of abnormal tangles of a protein (beta amyloid) in the brain
Intoxication - impairment of brain function by any toxic substance, including alcohol
Limbic system - part of the hypothalamus controlling appetite, thirst, sex, etc.
Reticular formation = reticular activating system - part of brain stem that keeps the body awake and alert
Dura mater - the tough, outermost layer of the meninges
Pia mater - the delicate, innermost meninx
Arachnoid layer - the middle meninx, containing a fluid-filled space and many spider-shaped (arachnoid) cells
Arachnoid villi - finger-like processes that allow cerebrospinal fluid in arachnoid layer to exchange materials with blood vessels
Blood-brain barrier - the many cell membranes that stand in the way of water-soluble substances flowing into the brain
Dorsal root ganglia - ganglia of sensory nerve cell bodies along the dorsal root of each spinal nerve
Chain ganglia - an interconnected series of sympathetic ganglia located lateral to the spinal cord