Chapter 4 – Key Terms
action potential change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers
All-or-Nothing law a principle that if a single nerve fiber if stimulated, it will always give a maximal response and produce an electrical impulse of a single amplitude
ascending tract central nervous system fibers carrying sensory information from the spinal cord or periphery to the brain
autonomic nervous system (ANS) functional division of the nervous system that is responsible for homeostatic reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue
axon single process of the neuron that carries an electrical signal (action potential) away from the cell body toward a target cell
axon hillock tapering of the neuron cell body that gives rise to the axon
axon terminal end of the axon, where there are usually several branches extending toward the target cell
cauda equina bundle of spinal nerve roots that descend from the lower spinal cord below the first lumbar vertebra and lie within the vertebral cavity; has the appearance of a horse’s tail
central nervous system (CNS) anatomical division of the nervous system located within the cranial and vertebral cavities, namely the brain and spinal cord
cerebellum region of the adult brain connected primarily to the pons that developed from the metencephalon (along with the pons) and is largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord
cerebral cortex outermost layer of gray matter in the brain, where conscious perception takes place
cerebral hemisphere one half of the bilaterally symmetrical cerebrum
cerebrum region of the adult brain that develops from the telencephalon and is responsible for higher neurological functions such as memory, emotion, and consciousness
dendrite one of many branchlike processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells
depolarization change in a cell membrane potential from rest toward zero
descending tract central nervous system fibers carrying motor commands from the brain to the spinal cord or periphery
excitable membrane cell membrane that regulates the movement of ions so that an electrical signal can be generated
glial cell one of the various types of neural tissue cells responsible for maintenance of the tissue, and largely responsible for supporting neurons
graded potential change in the membrane potential that varies in size, depending on the size of the stimulus that elicits it
hypothalamus major region of the diencephalon that is responsible for coordinating autonomic and endocrine control of homeostasis
initial segment first part of the axon as it emerges from the axon hillock, where the electrical signals known as action potentials are generated
integration nervous system f