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78 terms

The Biological Basis Of Behavior

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psychobiology
the area of psychology that focusses on the biological foundations of behavior and mental processes
neuroscience
the study of the brain and the nervous system
neurons
individual cells that are the smallest units of the nervous system
dendrites
short fibers that branch out fromt he 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 neurons
neurons that carry messages from sense organs to the spinal cord or brain
motor neurons
neurons that carry messages from the spinal cord or brain to the muscles and glands
interneurons
neurons that carry messages from one neuron to another
glial cells
cells that form the myelin sheath; they insulate and support neurons by holding them together, removing waste products, 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
the firing of a nerve cell
graded potential
a shift in the electrical charge 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 whena neuron is returning to its normal polarized state and will fire again only if the incoming message is much stronger than usual
synaptic space
tiny gap between the axon terminal of one neuron and the dendrites or cell body of the next neuron
terminal button
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 vesicle
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 neurotransmistter 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 in the hindbrain that controls certain refleces 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 the several places in the brain wehre 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 in the 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 fromt he motor areas are integrated
occipital lobe
part of the cerebral hemisphere that recieves 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 receptors 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 collosum
a think band of nerve fibers connecting the left and right cerebral cortex
spinal cord
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 blood stream
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 embeded 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 the day
pancreas
organ lying between the stomach and the small intestine; it secretes insulin and glucagon to regulate blood-sugar levels
pituitary gland
gland located on the underside of the brain; it produces the largest number of the body's hormones
gonads
the reproductive glands, testes in males and ovaries in females
adrenal glands
two endocrine glands located just above the kidneys
behavioral genetics
study of the relationships between heredity and behavior
evolutionary psychology
a subfield of psychology concerned with the origins of behaviors 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 in the chromosomes
chromosomes
pairs of threadlike bodies with 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 with 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 humas based on the assumption that if genes influence a certain trait, close relationships should be more similar on that trait that 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 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, which states that organisms best adapted to their environment tend to survive, transmitting their genetic characteristics to succeeding generations, whereas organisms with less adaptive characteristics tend to vanish from the earth