Biology 4: The Nervous System Flashcards
Oligodendrocytes
produce myelin in the central nervous system
Schwann Cells
produce myelin in the peripheral nervous system
Types of glial cells
astrocytes, ependymal cells, microglia, oligodendrocytes, and schwann cells
Astrocytes
nourish neurons and form the blood-brain barrier
Ependymal cells
line the ventricles of the brain and produce cerebrospinal fluid
Microglia
phagocytic cells that ingest and break down waste products and pathogens in the CNS
Summation
additive effect of multiple signals
Temporal Summation
multiple signals are integrated during a relatively short period of time
Spatial Summation
additive effects are based on the number and location of the incoming signals
Impulse Propagation
movement of an action potential down an axon, resulting in neurotransmitter release at the synaptic bouton and transmission of the impulse to the target neuron or organ
Saltatory Conduction
signal “hops” from node to node
Peripheral Nervous System (PNS)
made up of nerve tissue and fibers outside the brain and spinal cord, including all 31 pairs of spinal nerves and 10 of the 12 pairs of cranial nerves
Monosynaptic reflex arc
single synapse between the sensory neuron that receives the stimulus and the motor neuron that responds to it
relative refractory period
time during neural stimulation that requires greater than normal stimulation because the membrane is hyperpolarized
what is the orientation of neurons in the spinal cord?
sensory neurons enter on dorsal side with their cell bodies residing in dorsal root ganglia
motor neurons exit ventrally
polysynaptic reflex arc
sensory neuron can fire onto motor neuron as well as interneurons which fire onto other motor neurons
