branching extensions of a neuron that receive information and conduct impulses toward the cell body (soma).
extension of a neuron through which neural impulses are sent.
end point of a neuron where neurotransmitters are stored.
brief electrical charge that travels down the axon of a neuron
state of a neuron when it is at rest and capable of generating an action potential.
The principle stating that if a neuron fires, then it always fires at the same intensity; all action potentials have the same strength.
tiny, fluid-filled gap between the axon terminal of one neuron and the dendrite of another.
chemical messenger that travels across the synapse from one neuron to the next and influences whether a neuron will generate an action potential.
neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential, or "fire."
A neurotransmitter effect that makes it less likely that a receiving neuron will generate an action potential, or "fire.
Specialized cells in every sensory system of the body that can turn other kinds of energy into action potentials (neural impulses) that the brain can process.
Nerves that carry information from the sense receptors to the spinal cord and brain.
Nerve cells in the brain and spinal cord responsible for processing information.
drug that blocks the effect of a neurotransmitter.
rug that boosts the effect of a neurotransmitter.
central nervous system (CNS)
The brain and the spinal cord.
peripheral nervous system (PNS)
the sensory and motor nerves that connect the brain and the spinal cord to the rest of the body
somatic nervous system
The division of the peripheral nervous system that controls the body's skeletal muscles.
autonomic [aw-tuh-NAHM-ik] nervous system
division of the peripheral nervous system that controls the glands and muscles of the internal organs; its subdivisions are the sympathetic (arousing) division and the parasympathetic (calming) division.
part of the autonomic nervous system that arouses the body to deal with perceived threats.
The part of the autonomic nervous system that calms the body.
endocrine [EN-duh-krin] system
One of the body's two communication systems; a set of glands that produce hormones, chemical messengers that circulate in the blood.
chemical messenger produced by the endocrineglands and circulated in the blood.
The endocrine system's "master gland" that, in conjunction with an adjacent brain area, controls the other endocrine glands.
A research technique in which one person is studied in depth in the hope of revealing universal principles.
computerized axial tomography (CT or CAT)
A series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body.
magnetic resonance imaging (MRI)
A technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among types of soft tissue; this allows us to see structures within the brain.
An amplified recording of the waves of electrical activity that sweep across the brain's surface; these waves, measured by electrodes placed on the scalp, are helpful in evaluating brain function.
positron emission tomography (PET) scan
A visual display of brain activity.
The oldest part and central core of the brain; it begins where the spinal cord swells as it enters the skull and is responsible for automatic survival functions.
Located at the base of the brainstem, it controls basic life-support functions like heartbeat and breathing.
A nerve network in the brainstem that plays an important role in controlling wakefulness and arousal
The brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex.
The "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movements and balance.
A ring of structures at the border of the brainstem and cerebral cortex; it helps regulate important functions such as memory, fear, aggression, hunger, and thirst, and it includes the hypothalamus, the hippocampus, and the amygdala.
A neural structure lying below the thalamus; it helps regulate many of the body's maintenance activities, such as eating, drinking, and body temperature, and is linked to emotion.
A neural center located in the limbic system that wraps around the back of the thalamus; it helps process new memories for permanent storage.
An almond-shaped neural cluster in the limbic system that controls emotional responses, such as fear and anger.
cerebral [seh-REE-bruhl] cortex
The intricate fabric of interconnected neurons that form the body's ultimate control and information-processing center.
The long crevice that divides the cerebral cortex into the left and right hemispheres.
The large band of neural tissue that connects the two brain hemispheres and allows them to communicate with each other.
The portion of the cerebral cortex lying just behind the forehead that is involved in planning and judgment; it includes the motor cortex.
parietal [puh-RYE-uh-tuhl] lobes
The portion of the cerebral cortex lying at the top of the head and toward the rear; it includes the somatosensory cortex and general association areas used for processing information.
occipital [ahk-SIP-uh-tuhl] lobes
The portion of the cerebral cortex lying at the back of the head; it includes the primary visual processing areas of the brain.
The portion of the cerebral cortex lying roughly above the ears; it includes the auditory (hearing) areas of the brain.
A strip of brain tissue at the rear of the frontal lobes that controls voluntary movements.
A strip of brain tissue at the front of the parietal lobes that registers and processes body sensations.
The brain's ability to change, especially during childhood, by reorganizing after damage or experience.
A brain area of the left frontal lobe that directs the muscle movements involved in speech.
Wernicke's [VER-nik-ees] area
A brain area of the left temporal lobe involved in language comprehension and expression.