AP Psych Vocab Mods 9-11

Neuron

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

Cell body

The part of a neuron that contains the nucleus; the cell's life support center.

Dendrites

A neuron's often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body.

Axon

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

Myelin Sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

Glial Cells

Cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory.

Action Potential

Neural Impulse; a brief electrical charge that travels down an axon.

Threshold

The level of stimulation required to trigger a neural impulse.

Refractory Period

In neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.

All-or-None Response

A neuron's reaction of either firing (with a 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.

The tiny gap at this junction is called the synaptic gap or synaptic cleft.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that 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 to pleasure.

Agonist

A molecule that increases a neurotransmitter's action.

Antagonist

A molecule that inhibits or blocks a neurotransmitter's action.

Nervous System

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

Central Nervous System (CNS)

The brain and 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 body's tissues and sensory receptors to the brain and spinal cord.

Motor Efferent 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; they communicate internally and process information between the sensory inputs and motor outputs.

Somatic Nervous System

The division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system.

Automatic 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.

Sympathetic Division

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

Parasympathetic Division

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

Reflex

A simple, automatic response to a sensory stimulus, such as the knee-jerk response.

Endocrine System

The body's 'slow' chemical

communication system; a set of glands that secrete hormones into the bloodstream.

Hormones

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

Adrenal Glands

A pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and

norepinephrine) that help arouse the body in times of stress.

Pituitary Gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Brainstem

The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions.

Medulla

The base of the brainstem; controls heartbeat and breathing.

Thalamus

The brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

Reticular Formation

A nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal.

Cerebellum

The 'little brain' at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory.

Limbic System

Neural system (including the amygdala, hypothalamus, and hippocampus) located below the cerebral hemispheres; associated with emotions and drives.

Amygdala

Two lima-bean-sized neural clusters in the limbic system; linked to emotion.

Hypothalamus

A neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

Hippocampus

A neural center located in the limbic system; helps process for storage explicit (conscious) memories of facts and events.

Lesion

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

EEG

An amplified recording of the waves of electrical activity sweeping across the brain's surface. These waves are measured by electrodes placed on the scalp.

MEG

A brain imaging technique that measures magnetic fields from the brain's natural electrical activity.

CT Scan

A series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain's structure. (Also called CAT scan.)

PET Scan

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

MRI

A technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy.

fMRI

A technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. MRI scans show brain function as well as structure.