Chapter 19

Question 1

action potential

Answer 1

sudden change in electrical charge of a nerve cell membrane; the electrical signal by which neurons send info

Question 2

afferent

Answer 2

neurons or groups of neurons that bring info to the CNS; sensory nerve

Question 3

axon

Answer 3

long projection from a neuron that carries info from one nerve to another nerve or effector

Question 4

dendrite

Answer 4

short projection on a neuron that transmits info

Question 5

depolarization

Answer 5

opening of the sodium channels in a nerve membrane to allow the influx of positive sodium ions, reversing the membrane charge so it is no longer polarized

Question 6

effector cell

Answer 6

cell stimulated by a nerve; may be a muscle, a gland or another nerve cell

Question 7

efferent

Answer 7

neurons or groups of neurons that carry info from the CNS to an effector; motor neurons are efferent

Question 8

engram

Answer 8

short-term memory made up of a reverberating electrical circuit of action potentials

Question 9

forebrain

Answer 9

upper level of brain;consists of 2 cerebral hemispheres, where thinking and coordination of sensory and motor activity occur

Question 10

ganglia

Answer 10

a group of nerve bodies

Question 11

hindbrain

Answer 11

most primitive area of the brain, the brainstem; consists of the pons and medulla which control basic vital functions and arousal and the cerebellum which controls motor functions that regulate balance

Question 12

limbic system

Answer 12

area in the midbrain that is rich in epinephrine, norepinephrine and serotonin and seems to control emotions

Question 13

midbrain

Answer 13

the middle area of the brain; it consists of the hypothalamus and thalamus and includes the limbic system

Question 14

neuron

Answer 14

structural unit of the nervous system

Question 15

neurotransmitter

Answer 15

chemical produced by a nerve and released when the nerve is stimulated; reacts with specific receptor site to cause a reaction

Question 16

repolarization

Answer 16

return of a membrane to a resting state with more sodium ions outside the membrane and a relatively negative charge inside the membrane

Question 17

schwann cell

Answer 17

insulating cell found on nerve axons; allows “leaping” electrical conduction to speed the transmission of info and prevent tiring of the neuron

Question 18

soma

Answer 18

cell body of a neuron; contains the nucleus, cytoplasm and various granules

Question 19

synapse

Answer 19

junction between a nerve and an effector; consists of the presynaptic nerve ending, a space called the synaptic cleft, and the postsynaptic cell