Psychology Chapter 2 Vocabulary

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biological perspective

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concerned with the links between biology and behavior. Includes psychologists working in neuroscience, behavior genetics and evolutionary psychology. These researchers may call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, and biopsychologists

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neuron

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a nerve cell; the basic building block of the nervous system

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dendrites

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a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

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axon

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the neuron extension that passes messages hrough its branches to other neurons or to muscles or glands

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myelin sheath

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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

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glial cells (glia)

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cells in the nervous system that support, nourish, and protect neurons; they may also play aa role in learning, thinking, and memory

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action potential

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

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refractory period

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a period of inactivity after a neuron has fired

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threshold

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the level of stimulation required to trigger a neural impuse

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all-or-none response

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a neuron's reaction of either firing (with a full-strength response) or not firing

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synapse

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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

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neurotransmitters

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chemical messengers that cross 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

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reuptake

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a neurotransmitter's reabsorption by the sending neuron

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endorphins

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"morphine within" natural, opiate-like neurotransmitters linking to pain control and to pleasure

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agonist

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a molecule that increases a neurotransmitter's action

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antagonist

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a molecule that inhibits or blocks a neurotransmitter's action

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nervous system

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

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central nervous system (CNS)

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the brain and spinal chord

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peripheral nervous system (PNS)

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the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

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nerves

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bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs

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sensory (afferent) neurons

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

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motor (efferent) neurons

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

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interneurons

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neurons within the brain and spinal cord; communicate internally and process information between the sensory inputs and motor outputs

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somatic nervous system

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

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autonomic nervous system (ANS)

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the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). it's sympathetic division arouses and its parasympathetic division calms

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sympathetic nervous system

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the division of the autonomic nervous system that arouses the body; mobilizing its energy

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parasympathetic nervous system

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the division of the autonomic nervous system that calms the body; conserving its energy

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reflex

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

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endocrine system

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

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hormones

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chemical messengers that are manufactured by the endocrine glands; travel through the bloodstream and affect other tissue

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adrenal glands

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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

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pituitary gland

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

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lesion

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

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electroencephalogram (EEG)

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an amplified recording of the waves of electrical activity sweeping across the brain's surface. these waves are measures by electrodes on the scalp

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PET (positron emission tomography)

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

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MRI (magnetic resonance imaging)

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

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fMRI (functional MRI)

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

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brainstem

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

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medulla

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the base of the brain stem; controls heartbeat and breathing

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thalamus

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

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reticular formation

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a nerve network that travels though the brain stem into the thalamus and plays an important role in controlling arousal

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cerebellum

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the "little brain" at the rear of the brainstem; functions incluse