unit 4 flashcards
biological psychologists
the scientific study of the links between biological and psychological processes.
neuron
a nerve cell; the basic building block of the nervous system.
dendrites
the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body
axon
the neuron extension that passes and electrical messages through its branches to other neurons or to muscles or glands.
myelin sheath
a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.
action potential
a neural impulse; a brief electrical charge that travels down an axon
refractory period
a period of inactivity after a neuron has fired.
threshold
the level of stimulation required to trigger a neural impulse.
all-or-nothing response
a neuron’s reaction of either firing or not firing.
synapse
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, they travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
reuptake
a neurotransmitter’s reabsorption by the sending neuron.
endorphins
“morphine within”—natural, opiate-like neurotransmitters linked to pain control and to pleasure.
Agonist
A chemical that mimics the action of a neurotransmitter.
Antagonists
Chemical substances that block or reduce a cell’s response to the action of other chemicals or neurotransmitters.
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 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 sensory receptors to the brain and spinal cord.
motor (efferant) 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 that communicate internally and intervene between the sensory inputs and motor outputs.
Somatic nervous system
the division of the peripheral nervous system that controls the body’s skeletal muscles (skeletal nervous system)
Autonomic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs. It’s sympathetic system arouses and parasympathetic calms.
Sympathetic nervous system
the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations. (If you get scared)
Parasympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving its energy (Your PARents come home and calm you down)
Reflexes
simple, automatic responses to sensory stimuli, such as the knee-jerk response
Endocrine system
the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream
Hormones
chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues
Pituitary gland
“THE MASTER GLAND” the endocrine system’s most influential gland
under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands
Adrenal 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