Physiology Terminology Quiz 1

neuron

neural tissue cell that is primarily responsible for conducting electrical signals away from the cell body. It responds to stimuli.

glial cells

considered to be supporting cells, and many functions are directed at helping neurons complete their function for communication

afferent

conducts impulse toward the CNS

efferent

conducts impulse away from the CNS

somatic

motor neuron innervating skeletal muscles

autonomic

involuntary or unconscious; relating to the autonomic nervous system.

schwann cell

glial cell type in the PNS that provides the myelin insulation for axons in nerves

SNARE complex

proteins that function to anchor synpatic vesicles in axon terminals to the presynaptic plasma membrane

myelin sheath

lipid-rich layer of insulation that surrounds an axon, formed by oligodendrocytes in the CNS and Schwann cells in the PNS; facilitates the transmission of electrical signals

resting membrane potential

the difference in voltage measured across a cell membrane under steady-state conditions, typically -70 mV

depolarization

change in a cell membrane potential from rest toward zero; inside of the membrane becomes less negative compared to outside of the membrane

repolarization

return of the membrane potential to its normally negative voltage at the end of the action potential after depolarization

hyperpolarization

increase in negativity of inside of cell membrane with respect to the resting membrane potential

dendrite

one of many branch like processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells

voltage regulated channel

ion channel that opens because of a change in the charge distributed across the membrane where it is located

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

absolute refractory period

time during an action period when another action potential cannot be generated because the voltage-gated Na+ channel is inactivated

relative refractory period

time during the refractory period when a new action potential can only be initiated by a stronger stimulus than the current action potential because voltage-gated K+ channels are not closed

neurotransmitter

chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell

synapse

narrow junction across which a chemical signal passes from neuron to the next, initiating a new electrical signal in the target cell

ligand regulated gate

another name for an ionotropic receptor for which a neurotransmitter is the ligand

graded potential

change in the membrane potential that varies in size, depending on the size of the stimulus that elicits it

excitatory postsynaptic potential

graded potential in the postsynaptic membrane that is the result of depolarization and makes an action potential more likely to occur

inhibitory postsynaptic potential

graded potential in the postsynaptic membrane that is the result of hyperpolarization and makes an action potential less likely to occur

agonist

molecule that specifically binds to and activates a receptor protein

antagonist

molecule that binds and reduces the activity of receptor proteins

G-protein

association of three membrane associated protein subunits, regulated by guanosine

interneuron

neuron located in the CNS; also called association neuron