STUDY GUIDE FOR CHAPTER 7
In addition to the
definitions below, see also the summary on pages 236-237,
the chart of brain
divisions, and the illustrations on pages 209, 210, 211.
Neuron - a
nerve cell
Afferent (sensory) neurons - neurons carrying messages toward the central nervous system
Efferent (motor) neurons - neurons carrying messages away from the central nervous system
Dendrites - branching parts of a neuron, conducting impulses toward the cell body
Axon - elongated part of a neuron, carrying impulse rapidly away from the cell body
Myelin - a fatty substance surrounding most axons, secreted by Schwann cells
Nodes of Ranvier - constrictions in the myelin sheath between adjacent Schwann cells
Resting potential - normal -70 millivolt charge on nerve cell membranes when no nerve impulse is present
Depolarization - reduction or abolition of the resting potential
Repolarization - reestablishment of the resting potential
Synapse - a junction between two neurons, or between a neuron and a muscle cell
Receptor - a membrane protein to which a molecule may bind, setting off a response
Reflex - a rapid, automatic response that does not involve the brain
Neuroglia - cells in nervous tissue other than neurons
Gray matter - nervous tissue with many cell bodies and little or no myelin
White matter - nervous tissue with many myelinated fibers
Nerve - a bundle of axons outside the central nervous system
Tract - a bundle of axons within the central nervous system
Ganglion - a cluster of nerve cell bodies outside the CNS
Nucleus - a cluster of nerve cell bodies within the brain
Central nervous system (CNS) - the brain and spinal cord
Peripheral nervous system - the cranial nerves (from the brain), peripheral nerves (from the spinal cord),
and the special sensory organs (eye, ear, olfactory organs, taste buds, cutaneous receptors)
Forebrain
(prosencephalon) - front of the major brain divisions, including
telencephalon & diencephalon
Telencephalon - paired part of the forebrain, including cerebral hemispheres, olfactory lobes & bulbs, etc
Diencephalon - medial part of the forebrain, including epithalamus (with pineal body, ant. choroid plexus, etc.), thalamus, and hypothalamus (with optic chiasma, infundibulum, pituitary, etc.)
Mesencephalon - middle of the major brain divisions, including the superior & inferior colliculi
Rhombencephalon - hind part of the brain, including the metencephalon and myelencephalon
Metencephalon - portion of the hind brain including the pons and cerebellum
Myelencephalon - part of the hind brain incl. the medulla oblongata, continuing into the spinal column
Cerebrum - major part of the telencephalon, involved in higher thought, consciousness, speech, etc.
Cerebellum - dorsal portion of hind brain, responsible for balance and coordination of muscle activity
Brain stem - all the brain except for the cerebrum and cerebellum
Cerebrospinal fluid - fluid inside the spinal canal and brain cavities
Somatic - portion of the nervous system under conscious control and awareness
Visceral - portion of the nervous system that works without need of conscious control
Autonomic - visceral motor fibers that respond on their own (“self-governing”) without conscious control
Meninges - connective tissue layers covering and protecting the brain