inherited characteristic that improves an organism's ability to survive and reproduce in a particular environment
a specific time in development when certain skills or abilities are most easily learned
a layer of fatty tissue segmentally encasing the fibers of many neurons enables vastly greater transmission speed of neural impulses
The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.
the stable, negative electrical charge across the cell membrane of a resting neuron
Absolute Refractory Period
minimum length of time after an action potential during which another action potential cannot begin
An electric potential that increases the likelihood that a postsynaptic neuron will fire action potentials.
An electric potential that decreases the likelihood that a postsynaptic neuron will fire action potentials.
researchers assess hereditary influence by examining blood relatives to see how much they resemble one another on a specific trait
An entire family of internally produced chemicals that resemble opiates in structure and effects
Peripheral Nervous System
System that includes all those nerves that lie outside the brain and spinal chord
Somatic Nervous System
The part of the peripheral nervous system that controls voluntary movement of skeletal muscles
Afferent Nerve Fibers
Axons that carry information inward to the central nervous system from the periphery of the body
Efferent Nerve Fibers
Axons that carry information outward from the central nervous system to the periphery of the body.
Autonomic Nervous System
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.
The branch of the autonomic nervous system that mobilizes the body's resources for emergencies.
the branch of the nervous system that automatically calms us down when the reason for arousal has passed
Cerebral Fluid (CSF)
A solution that fills the hollow cavities of the brain and circulates around the brain and spinal cord. Provides nourishment, cushions, and removes wastes.
studies of identical and fraternal twins to determine the relative influence of heredity and environment on human behavior
Procedure involves inserting an electrode into a brain structure and passing a high-frequency current through it to burn the tissue and disable the structure
Electric Stimulation of the Brain
Method that involves sending a weak electric current into a brain structure to stimulate (activate) it.
part of the brain between the spinal cord and the midbrain, consisting of the pons, medulla, and cerebellum
top of the brain which includes the thalamus, hypothalamus, and cerebral cortex; responsible for emotional regulation, complex thought, memory aspect of personality; largest and most complex region
the structure of the brain that relays messages from the sense organs to the cerebral cortex (except smell)
a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion
A group of neural structures at the base of the cerebral hemispheres that is associated with emotion and motivation
the intricate fabric of interconnected neural cells that covers the cerebellum; the body's ultimate control and information-processing center
the large band of neural fibers connecting the two brain hemispheres and carrying messages between them
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
a condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them
System of glands that secrete chemicals into the bloodstream that help control bodily functioning
The sum of an individuals own reproductive success, plus the effects the organism has on the reproductive success of related others
A mating system in which one male and one female mate exclusively, or almost exclusively, with one another
An inter disciplinary field that studies the influence of genetic factors on behavioral traits
twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms
twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment.
The process of determining the location and chemical sequence of specific genes on specific chromosomes
process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest
What each sex invests-in terms of time, energy, survival risks, and forgone opportunities-to produce and nurture offspring.