Chapter 2 Flashcards

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1
Q

NEURON

A

a specialized cell transmitting nerve impulses; a nerve cell.

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2
Q

DENDRITES

A

a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body.

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3
Q

CELL BODY

A

the nucleus-containing central part of a neuron exclusive of its axons and dendrites that is the major structural element of the gray matter of the brain and spinal cord, the ganglia, and the retina — called also perikaryon, soma.

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4
Q

AXON

A

the long threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells.

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5
Q

MYELIN SHEATH

A

the insulating covering that surrounds an axon with multiple spiral layers of myelin,

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6
Q

TERMINAL BUTTONS

A

Tiny bulblike structures at the end of the dendrites, which contain neurotransmitters that carry the neuron’s message into the synapse.

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7
Q

NEUROTRANSMITTERS

A

a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.

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8
Q

SYNAPSE

A

a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.

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9
Q

RECEPTOR

SITES

A

the part of a nerve that receives and reads chemical signals (neurotransmitters) from other nerves to transmit the electrical signals that transfer information through the brain and nervous system.

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10
Q

THRESHOLD

A

the level of strength a stimulus must reach to be detected.

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11
Q

ACTION POTENTIAL

A

threshold in a neuron is the point of depolarization at which the neuron fires, transmitting information to another neuron.

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12
Q

ALL-OR-NONE

PRINCIPLE

A

law is a principle that states that the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus.

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13
Q

NEURAL FIRING

A

An action potential is part of the process that occurs during the firing of a neuron. During the action potential, part of the neural membrane opens to allow positively charged ions inside the cell and negatively charged ions out. … When the charge reaches +40 mv, the impulse is propagated down the nerve fiber.

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14
Q

EXCITATORY

NEUROTRANSMITTERS

A

Excitatory neurotransmitters are neurotransmitters that increase the likelihood that a nerve cell will produce an action potential, an electrochemical impulse that nerve cells use to transmit signals

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15
Q

INHIBITORY

NEUROTRANSMITTERS

A

A neurotransmitter that generally activates receptors that have reversal potentials more negative than threshold for action potential firing.

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16
Q

ACETYLCHOLINE

A

a compound that occurs throughout the nervous system, in which it functions as a neurotransmitter.

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17
Q

DOPAMINE

A

a compound present in the body as a neurotransmitter and a precursor of other substances including epinephrine.

18
Q

ENDORPHINS

A

any of a group of hormones secreted within the brain and nervous system and having a number of physiological functions. They are peptides that activate the body’s opiate receptors, causing an analgesic effect.

19
Q

SEROTONIN

A

a compound present in blood platelets and serum that constricts the blood vessels and acts as a neurotransmitter.

20
Q

AFFERENT

NEURONS

A

are pathways that carry sensory information from the body to the central nervous system (the brain and spinal cord).

21
Q

EFFERENT

NEURONS

A

are conducting cells that carry information from the central nervous system (the brain and spinal cord) to muscles and organs throughout the body.

22
Q

CENTRAL
NERVOUS
SYSTEM

A

the complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.

23
Q

SPINAL CORD

A

the cylindrical bundle of nerve fibers and associated tissue that is enclosed in the spine and connects nearly all parts of the body to the brain, with which it forms the central nervous system.

24
Q

PERIPHERAL
NERVOUS
SYSTEM

A

the nervous system outside the brain and spinal cord.

25
Q

SOMATIC
NERVOUS
SYSTEM

A

Major functions of the somatic nervous system include voluntary movement of the muscles and organs and reflex movements. In the process of voluntary movement, sensory neurons carry impulses to the brain and the spinal cord

26
Q

AUTONOMIC

NERVOUS SYSTEM

A

the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.

27
Q

SYMPATHETIC
NERVOUS
SYSTEM

A

the part of the autonomic nervous system that contains chiefly adrenergic fibers and tends to depress secretion, decrease the tone and contractility of smooth muscle, and increase heart rate — compare parasympathetic nervous system.

28
Q

PARASYMPATHETIC

NERVOUS SYSTEM

A

The part of the involuntary nervous system that serves to slow the heart rate, increase intestinal and glandular activity, and relax the sphincter muscles. The parasympathetic nervous system, together with the sympathetic nervous system, constitutes the autonomic nervous system

29
Q

LESIONS

A

a region in an organ or tissue that has suffered damage through injury or disease, such as a wound, ulcer, abscess, tumor, etc.

30
Q

ELECTROENCEPHALOGRAM

A

a test or record of brain activity produced by electroencephalography.

31
Q

COMPUTERIZED AXIAL TOMOGRAPHY

A

Tomography in which computer analysis of a series of cross-sectional scans made along a single axis of a bodily structure or tissue is used to construct a three-dimensional image of that structure.

32
Q

MAGNETIC RESONANCE IMAGING

A

a form of medical imaging that measures the response of the atomic nuclei of body tissues to high-frequency radio waves when placed in a strong magnetic field, and that produces images of the internal organs.

33
Q

POSITRON EMISSION

TOMOGRAPHY

A

positron emission tomography (PET) scan is an imaging test that helps reveal how your tissues and organs are functioning. A PET scan uses a radioactive drug (tracer) to show this activity. … The tracer may be injected, swallowed or inhaled, depending on which organ or tissue is being studied.

34
Q

FUNCTIONAL MRI

A

Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled.

35
Q

HINDBRAIN

A

the lower part of the brainstem, comprising the cerebellum, pons, and medulla oblongata.

36
Q

MEDULLA

A

the inner region of an organ or tissue, especially when it is distinguishable from the outer region or cortex (as in a kidney, an adrenal gland, or hair).

37
Q

PONS

A

the part of the brainstem that links the medulla oblongata and the thalamus.

38
Q

CEREBELLUM

A

“Little brain” the part of the brain at the back of the skull in vertebrates. Its function is to coordinate and regulate muscular activity.

39
Q

MIDBRAIN

A

a small central part of the brainstem, developing from the middle of the primitive or embryonic brain.

40
Q

RETICULAR FORMATION

A

a diffuse network of nerve pathways in the brainstem connecting the spinal cord, cerebrum, and cerebellum, and mediating the overall level of consciousness.