The bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body.
A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.
A neural impulse; a brief electrical charge that travels down an axon. The action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane
The level of stimulation that must be exceeded in order for the neuron to fire, or generate an electrical impulse.
The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.
A neurotransmitter that enables learning and memory and also triggers muscle contraction.
A neurotransmitter that affects hunger,sleep,arousal,and mood. Appears in lower than normal levels in depressed persons.
Neurotransmitter that is involved in arousal and the fight-or-flight system (also mood, sleep, and learning).
A major inhibitory neurotransmitter. Not enough=seizures, tremors, and insomnia., gamma-aminobutyric acid.
The body system of nervous tissues--organized into the brain,spinal courd, and nerves--that send and receive messages and integreate the body's activities.
Central Nervous System
The portion of the vertebrate nervous system consisting of the brain and spinal cord.
Peripheral Nervous System
Division of the nervous system that connects the central nervous system to the rest of the body.
Bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sense organs.
Neurons that carry incoming information from the sensory receptors to the brain and spinal cord.
Neurons that carry outgoing information from the central nervous system to the muscles and glands.
Central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs.
Autonomic Nervous System
The part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands.
Sympathetic Nervous System
The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.
Parasympathetic Nervous System
Division of the Autonomic Nervous System that calms the body, conserving its energy.
Somatic Nervous System
The division of the peripheral nervous system that controls the body's skeletal muscles. also called the skeletal nervous system.
The body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream.
Chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another.
A pair of endocrine glands just above the kidneys. the adrenals secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress.
The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.
Tissue destruction. a brain lesion is a naturally or experimentally caused destruction of brain tissue.
Eletroencephalogram; an amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp.
Position Emission Tomography; a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.
A technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain.
A technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. MRI scans show brain anatomy; fMRI scans show brain function.
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.
A nerve network in the brainstem that plays an important role in controlling arousal.
The brain's sensory switchboard, 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.
The "little brain" attached to the rear of the brainstem; its functions include processing sensory input and coordinating movement output and balance.
A doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres; associated with emotions such as fear and aggression and drives such as those for food and sex. Includes the hippocampus, amygdala, and hypothalamus.
Two almond-shaped neural clusters that are components of the limbic system and are linked to emotion.
A neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion.
The intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center.
The portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.
The portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments.
The portion of the cerebral cortex lying at the back of the head; includes the visual areas, which receive visual information from the opposite visual field.
Portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear. Primary area for hearing, understanding language (Wernicke's area), understanding music/tonality, processing smell.
The area at the front of the parietal lobes that registers and processes body touch and movement sensations.
Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking.
Impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to wernicke's area (impairing understanding). (Inability to use or understand language (spoken or written) because of a brain lesion.)
Controls language expression-an aread of the frontal, usually in the left hemisphere, that directs the muscle movements involved in speech.
Controls language reception-a brain area involved in language comprehension and expression;usually in the left temporal lobe.
The ability of other parts of the brain to take over functions of damaged regions. Declines as hemispheres of the cerebral cortex lateralize.
The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.