Unit 3: Biological Bases of Behavior Flashcards
modules done so far: 9, 10, 25
terminal branches
the ends of the axon containing terminal buttons which hold synaptic vesicles that store neurotransmitters
neuron
a nerve cell; the basic building block of the nervous system
cell body
the part of a neuron that contains the nucleus; the cell’s life support center
dendrites
a neuron’s often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body
axon
the neuron extension that passes messages through its branches to other neurons or to muscles or glands
myelin sheath (my-uh-lin)
a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next
glial cells (glia)
cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory
action potential
a neural impulse; a brief electrical charge that travels down an axon
threshold
the level of stimulation required to trigger a neural impulse
refractory period
in neural processing, a brief resting pause occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state
all-or-none response
a neuron’s reaction of either firing (with a full-strength response) or not firing
synapse (sin-aps)
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. the tiny gap at this junction is called the synaptic gap or synaptic cleft
neurotransmitters
chemical messengers that cross the synaptic gaps between neurons. when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby inflecting whether that neuron will generate a neural impulse
reuptake
a neurotransmitter’s reabsorption by the sending neuron
endorphins (en-dor-fins)
“morphine within” - natural, opiate-like neutrotransmitters linked to pain control and to pleasure
agonist
a molecule that increases a neurotransmitter’s actions
antagonist
a molecule that inhibits or blocks a neurotransmitter’s action
nervous system
the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems
central nervous system (CNS)
the brain and the spinal cord
peripheral nervous system (PNS)
the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body
nerves
bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs
sensory (afferent) neurons
neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord
motor (efferent) neurons
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
interneurons
neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs
somatic nervous system
the division of the peripheral nervous system that controls the body’s skeletal nervous system
autonomic (aw-tuh-nahm-ik_ nervous system (ans)
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). its sympathetic division arouses; its parasympathetic division calms
sympathetic nervous system
the division of the autonomic nervous system that arouses the body, mobilizing its energy
parasympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving its energy
reflex
a simple, automatic response to a sensory stimulus, such as the knee-jerk response
endocrine (en-duh-krin) system
the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream
adrenal (ah-dreen-el) glands
a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress
pituitary gland
the endocrine system’s most influential gland. under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands
gate-control theory
the theory that the spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass on to the brain. the “gate” is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers and closed by activity in larger fibers or by information coming from the brain