Unit 3 Vocab (Part 1)

Question 1

Neuron

Answer 1

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

Question 2

Cell body

Answer 2

The part of a neuron that contains the nucleus; the cells, life support center.

Question 3

Dendrites

Answer 3

A neurons often bushy, branching extensions that receive an integrate messages, conducting impulses toward the cell body.

Question 4

Axon

Answer 4

The neuron extension that passes Messages through its branches to other neurons, or to muscles or glands.

Question 5

Myelin sheath

Answer 5

A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neutral impulses, hopped from one node to the next.

Question 6

Glial cells

Answer 6

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

Question 7

Action potential

Answer 7

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

Question 8

Threshold

Answer 8

The level of simulation required to trigger a neutral impulse.

Question 9

Refractory period

Answer 9

In neutral 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.

Question 10

All-or-none response

Answer 10

A neurons reaction of either firing (with a full- strength response) or not firing.

Question 11

Synapse

Answer 11

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.

Question 12

Neurotransmitters

Answer 12

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.

Question 13

Reuptake

Answer 13

A neurotransmitter’s reabsorption by the sending neuron.

Question 14

Endorphins

Answer 14

‘morphine within’ - natural, opiate-like neurotransmitters linked to pain control and to pleasure.

Question 15

Agonist

Answer 15

A molecule that increases a neurotransmitter’s action.

Question 16

Antagonist

Answer 16

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

Question 17

Nervous System

Answer 17

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

Question 18

Central Nervous System (CNS)

Answer 18

The brain and spinal cord.

Question 19

Peripheral Nervous System (PNS)

Answer 19

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

Question 20

Nerves

Answer 20

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

Question 21

Sensory (afferent) Neurons

Answer 21

Neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord.

Question 22

Motor (efferent) Neurons

Answer 22

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

Question 23

Interneurons

Answer 23

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

Question 24

Somatic Nervous System

Answer 24

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

Question 25

Autonomic Nervous System (ANS)

Answer 25

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.

Question 26

Sympathetic Nervous System

Answer 26

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

Question 27

Parasympathetic Nervous System

Answer 27

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

Question 28

Reflex

Answer 28

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

Question 29

Endocrine System

Answer 29

The body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.

Question 30

Hormones

Answer 30

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

Question 31

Adrenal Glands

Answer 31

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.

Question 32

Pituitary Gland

Answer 32

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

Question 33

Lesion

Answer 33

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

Question 34

EEG (electroencephalogram)

Answer 34

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.

Question 35

MEG (magnetoencephalography)

Answer 35

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

Question 36

CT (computed tomography) Scan

Answer 36

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.)

Question 37

PET (positron emission tomography) Scan

Answer 37

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

Question 38

MRI (magnetic resonance imaging)

Answer 38

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

Question 39

fMRI (functional MRI)

Answer 39

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