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Psych Ch 2 Vocab
The Biological Basis of Behavior
Question | Answer |
---|---|
psychobiology | the area of psychology that focuses on the biological foundations of behavior and mental processes |
neurons | individual cells that are the smallest units of the nervous system |
dendrites | short fibers that branch out from the cell body and pick up incoming messages |
axon | single long fiber extending from the cell body; it carries outgoing messages |
nerve (tract) | group of axons bundled together |
myelin sheath | white fatty covering found on some axons |
sensory (afferent) neurons | neurons that carry messages from sense organs to the spinal cord or brain |
motor (efferent) neurons | neurons that carry messages from the spinal cord or brain to the muscles and glands |
interneurons (association neurons) | neurons that carry messages from one meuron to another |
glial cells (glia) | cells that form the myelin sheath; they insulate and support neurons by holding them together, removing waste prodcuts, and preventing harmful substances from passing from the bloodstream into the brain |
ions | electrically charged particles found both inside and outside the neuron |
resting potential | electrical charge across a neuron membrane due to excess positive ions concentrated on the outside and excess negative ions on the inside |
polarization | the condition of a neuron when the inside is negatively charged relative to the outside; for example, when the neuron is at rest |
neural impulse (action potential) | the firing of a nerve cell |
graded potential | a shift the electrical charge of in a tiny area of a neuron |
threshold of excitation | the level an impulse must exceed to cause a neuron to fire |
all-or-none law | principle that the action potential in a neuron does not vary in strength; the neuron either fires at full strength or it does not fire at all |
absolute refractory period | a period after firing when a neuron will not fire again no matter how strong the incoming messages may be |
relative refractory period | a period after firing when a neuron is returning to its normal polarized state and will fire again only if the incoming message is much stronger than usual |
synaptic space (synaptic cleft) | tiny gap betweeen the axon terminal of one neuron and the dendrites or cell body of the next neuron |
terminal button (synaptic knob) | structure at the end of an axon terminal branch |
synapse | area composed of the axon terminal of one neuron, the synaptic space, and the dendrite or cell body of the next neuron |
synaptic vesicles | tiny sacs in a terminal button that release chemicals into the synapse |
neurotransmitters | chemicals released by the synaptic vesicles that travel across the synaptic space and affect adjacent neurons |
receptor site | a location on a receptor neuron into which a specific neurotransmitter fits like a key into a lock |
neural plasticity | the ability of the brain to change in response to experience |
neurogenesis | the growth of new neurons |
central nervous system | division of the nervous system that consists of the brain and spinal cord |
peripheral nervous system | division of the nervous system that connects the central nervous system to the rest of the body |
hindbrain | area containing the medulla, pons, and cerebellum |
cerebellum | structure int he hindbrain that controls certain reflexes and coordinates the body's movements |
midbrain | region between the hindbrain and the forebrain; it is important for hearing and sight, and it is one of several places in the brain where pain is registered |
thalamus | forebrain region that relays and translates incoming messages from the sense receptors, except those for smell |
hypothalamus | forebrain region that governs motivation and emotional responses |
reticular formation (RF) | network of neurons int he hindbrain, the midbrain, and part of the forebrain whose primary function is to alert and arouse the higher parts of the brain |
limbic system | ring of structures that play a role in learning and emotional behavior |
cerebral cortex | the outer surface of the two cerebral hemispheres that regulates most complex behavior |
association areas | areas of the cerebral cortex where incoming messages from the separate senses are combined into meaningful impressions and outgoing messages from the motor areas are integrated |
occipital lobe | part of the cerebral hemisphere that receives and interprets visual information |
temporal lobe | part of the cerebral hemisphere that helps regulate hearing, balance and equilibrium, and certain emotions and motivations |
parietal lobe | part of the cerebral cortex that receives sensory information from throughout the body |
primary somatosensory cortex | area of the parietal lobe where messages from the sense recptors are registered |
frontal lobe | part of the cerebral cortex that is responsible for voluntary movement; it is also important for attention, goal-directed behavior, and appropriate emotional experiences |
primary motor cortex | the section of the frontal lobe responsible for voluntary movement |
corpus callosum | a thick band of nerve fibers connecting the left and right cerebral cortex |
spinal cords | complex cable of neurons that runs down the spine, connecting the brain to most of the rest of the body |
somatic nervous system | the part of the peripheral nervous system that carries messages from the senses to the central nervous system and between the central nervous system and the skeletal muscles |
autonomic nervous system | the part of the peripheral nervous system that carries messages between the central nervous system and the internal organs |
sympathetic division | branch of the autonomic nervous system; it prepares the body for quick action in an emergency |
parasympathetic division | branch of the autonomic nervous system; it calms and relaxes the body |
endocrine glands | glands of the endocrine system that release hormones into the bloodstream |
hormones | chemical substances released by the endocrine glands; they help regulate bodily activities |
thyroid gland | endocrine gland located below the voice box; it produces the hormone thyroxin |
parathyroids | four tiny glands embedded in the thyroid; they secrete parathormone |
pineal gland | a gland located roughly in the center of the brain that appears to regulate activity levels over the course of a day |
pancreas | organ lying between the stomach and small intestine; it secretes insulin and glucagon to regulate blood-sugar levels |
pituitary gland | gland located on the inderside of the brain; it produces the largest number of the body's hormones |
adrenal glands | two endocrine glands located just above the kidneys |
behavior genetics | study of the relationship between heredity and behavior |
evolutionary psychology | a subfield of psychology concerned with the origins of behaviiors and mental processes, their adaptive value, and the purposes they continue to serve |
genetics | study of how traits are transmitted from one generation to the next |
genes | elements that control the transmission of traits; they are found on the chromosomes |
chromosomes | pairs of threadlike bodies within the cell nucleus that contain the genes |
deoxyribonucleic acid (DNA) | complex molecule in a double-helix configuration that is the main ingredient of chromosomes and genes and forms the code for all genetic information |
human genome | the full complement of genes within a human cell |
dominant gene | member of a gene pair that controls the appearance of a certain trait |
recessive gene | member of a gene pair that can control the appearance of a certain trait only if it is paired with another recessive gene |
polygenic inheritance | process by which several genes interact to produce a certain trait; responsible for our most important traits |
strain studies | studies of the heritability of behavioral traits using animals that have been inbred to produce strains that are genetically similar to one another |
selection studies | studies that estimate the heritability of a trait by breeding animals with other animals that have the same trait |
family studies | studies of heritability in humans based on the assumption that if genes influence a certain trait, close relatives should be more similar on that trait than distant relatives |
twin studies | studies of identical and fraternal twins to determine the relative influence of heredity and environment on human behavior |
identical twins | twins developed from a single fertilized ovum and therefore identical in genetic makeup at the time of conception |
fraternal twins | twins developed from two separate fertilized ova and therefore different in genetic makeup |
adoption studies | research carried out on children, adopted at birth by parents not related to them, to determine the relative influence of heredity and environment on human behavior |
natural selection | the mechanism proposed by Darwin in his theory of evolution; organisms best adapted to their environment tend to survive, transmitting their genetic chars to succeeding generations, whereas organisms with less adaptive chars tend to vanish from the earth |