AP Psych

Biological psychology

The scientific study of the links between biological (genetic, neural, hormonal) and psychological processes.

Neuron

A nerve cell; the basic building block of the nervous system.

Dendrites

Bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body.

Axon

The neuron extension that passes messages through its branches to other neurons or to muscles or glands.

Myelin sheath

A fatty tissue layer segmentally encasing the axons of some neurons, enabling greater transmission speed.

Action potential

A neural impulse; a brief electrical charge that travels down an axon.

Refractory period

A period of inactivity after a neuron has fired.

Threshold

The level of stimulation required to trigger a neural impulse.

All-or-none response

A neuron's reaction of either firing (with full strength response) or not firing.

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.

Neurotransmitters

Chemical messengers that cross synaptic gaps between neurons to influence whether the receiving neuron will generate a neural impulse.

Reuptake

A neurotransmitter’s reabsorption by the sending neuron.

Endorphins

'Morphine within'; natural opiate-like neurotransmitters linked to pain control and pleasure.

Agonist

A molecule that, by binding to a receptor site, stimulates a response.

Antagonist

A molecule that, by binding to a receptor site, inhibits or blocks a response.

Nervous system

The body’s speedy, electrochemical communication network, consisting of all nerve cells of the peripheral and central nervous systems.

Central nervous system (CNS)

The brain and the spinal cord.

Peripheral nervous system (PNS)

The sensory and motor neurons that connect the central nervous system 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 (afferent) neurons

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

Motor (efferent) neurons

Neurons that carry outgoing information from the brain and spinal cord to muscles and glands.

Interneurons

Neurons within the brain and spinal cord that communicate internally and intervene between sensory inputs and motor outputs.

Somatic nervous system

The division of the peripheral nervous system that controls the body’s skeletal muscles.

Autonomic nervous system (ANS)

The part of the peripheral nervous system that controls the glands and muscles of the internal organs.

Sympathetic nervous system

The division of autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.

Parasympathetic nervous system

The division of the autonomic nervous system that calms the body, conserving its energy.

Reflex

A simple, automatic response to a sensory stimulus.

Endocrine system

The body’s 'slow' chemical communication system; a set of glands that secrete hormones into the bloodstream.

Hormones

Chemical messengers manufactured by endocrine glands that travel through the bloodstream and affect other tissues.

Adrenal glands

A pair of endocrine glands that secrete hormones that help arouse the body in times of stress.

Pituitary gland

The endocrine system’s most influential gland, regulating growth and controlling other endocrine glands.

Lesion

Tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue.

Electroencephalogram (EEG)

An amplified recording of the waves of electrical activity sweeping across the brain’s surface.

CT (computer tomography) scan

A series of X-ray photographs taken from different angles and combined into a composite representation of brain structure.

PET (positron emission tomography) scan

A visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.

MRI (magnetic resonance imaging)

A technique that uses magnetic fields and radio waves to produce images of soft tissue.