- autonomic nervous system (ANS): part of the PNS that controls internal biological functions
- central nervous system (CNS): brain and spinal cord
- computerized axial tomography(CAT): imaging technique used to see which brain areas are being activated while performing tasks
- electroencephalograph (EEG): machine used to record electrical activity of large portions of the brain
- endocrine system: chemical communication system, using hormones, by which messages are sent through the bloodstream
- forebrain: part of the brain that covers the brain's central core
- fraternal twins: twins who came from two different eggs fertilized by two different sperm
- genes: basic building blocks of heredity
- heredity: genetic transmission of characteristics from parents to their offspring
- hindbrain: part of the brain located at the rear base of the skull involved in basic processes of life
- hormones: chemical substances that carry messages through the body in blood
- identical twins: twins who came from one fertilized egg; twins having the same heredity
- lobes: different regions into which the cerebral cortex is divided
- magnetic resonance imaging(MRI): imaging technique used to study brain structure and activity
- midbrain: small part of brain above the pons that integrates sensory information and relays it upward
- neurons: long, thin cells of nerve tissue along which messages travel to and from the brain
- neurotransmitters: the chemicals released by neurons, which determine the rate which other neurons fire
- peripheral nervous system(PNS): nerves branching out from the spinal cord
- pituitary gland: center of control of the endocrine system that secretes a large number of hormones
- Positron Emission tomography: an imaging technique used to see which brain areas are being activated while performing tasks
- somatic nervous system(SNS): part of the PNS that controls voluntary movement of skeletal muscles
- spinal cord: nerves that run up and down the length of the back and transmit most messages between body and brain
- synapse: gap between individual nerve cells