Unit 2: Biological Basis of Behavior

Nervous System

The master controlling and communicating system of the body; consists of the central and peripheral nervous systems.

Central Nervous System (CNS)

The brain and spinal cord; the body's central information processor.

Peripheral Nervous System (PNS)

The sensory and motor neurons that connect the CNS 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 Neurons

Neurons that carry incoming information from the sensory receptors to the brain and spinal cord.

Motor 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.

Sympathetic Nervous System

The division of the autonomic NS that arouses the body for action (fight-or-flight); uses norepinephrine.

Parasympathetic Nervous System

The division of the autonomic NS that calms the body (rest-and-digest); conserves energy.

Endocrine System

The body's "slow" chemical communication system; glands secrete hormones into the bloodstream.

Hormones

Chemical messengers released by endocrine glands that travel through the bloodstream and affect body functions.

Adrenal Glands

Glands on top of the kidneys that secrete epinephrine (adrenaline) and norepinephrine during stress.

Pituitary Gland

The "master gland" of the endocrine system, regulated by the hypothalamus; releases hormones that direct other glands.

Brainstem

The oldest part of the brain; controls basic survival functions like heartbeat, breathing, and swallowing.

Medulla

The base of the brainstem; controls heartbeat, breathing, and blood pressure.

Thalamus

The brain's sensory "relay station"; routes incoming sensory signals (except smell) to cortical areas.

Cerebellum

The "little brain" at the rear of the brainstem; coordinates voluntary movement and balance.

Amygdala

Two almond-shaped clusters of neurons linked to emotion, especially fear and aggression.

Hippocampus

A limbic structure critical for processing and transferring new explicit memories to long-term storage.

Corpus Callosum

The large band of neural fibers connecting the two brain hemispheres; allows them to communicate.

Hypothalamus

A limbic structure that regulates body temperature, hunger, thirst, sex drive, and the endocrine system.

Spinal Cord

The pathway connecting the brain to the peripheral nervous system, responsible for transmitting messages and coordinating simple reflexes.

Cerebral Cortex

The outer surface of the brain's cerebral hemispheres; seat of higher mental functions.

Adolescence

The transition period from childhood to adulthood, roughly between the ages of 12 and 20.

Puberty

The period of sexual maturation during which a person becomes capable of reproduction.

Identity

Erikson's adolescent task of developing a consistent and comfortable sense of self by testing and integrating various roles.

Social Identity

The "we" aspect of our self-concept that comes from our group memberships.

Intimacy

Erikson's young adulthood task of forming close, loving, and committed relationships.

Emerging Adulthood

A period from 18 to the mid-20s of identity exploration before achieving full adult status and independence.

Menopause

The time of natural cessation of menstruation; refers to the biological changes a woman experiences as her ability to reproduce declines.

Social Clock

The culturally preferred timing of major life events such as marriage, parenthood, and retirement.