Chapter 48 and 49: Neurons and Nervous System

Question 1

neurons

Answer 1

cells that conduct and store information in the nervous system

Question 2

cell body

Answer 2

part of the neuron that houses most of the cytoplasm, nucleus, etc.

Question 3

dendrites

Answer 3

branched extensions at receiving end

Question 4

axon

Answer 4

extends from neuron to cell it acts on

Question 5

synapse

Answer 5

connection between neurons; excitement passed chemically

Question 6

presynaptic cells

Answer 6

cell that releases neurotransmitters

Question 7

neurotransmitters

Answer 7

chemical messages between neurons

Question 8

postsynaptic cell

Answer 8

cell that receives neurotransmitters

Question 9

membrane potential

Answer 9

voltage difference across cell membrane; difference in charge between inside and outside

Question 10

resting potential

Answer 10

membrane potential of a neuron that isn’t excited

Question 11

ATP-powered sodium-potassium pump

Answer 11

brings K+ in, sends Na+ out

Question 12

ion channels

Answer 12

let ions move down their gradients

Question 13

potassium ion channels

Answer 13

K+ always leaking out

Question 14

sodium ion channels

Answer 14

Na+ builds up outside

Question 15

voltage potential

Answer 15

created by net movement of charge

Question 16

equilibrium potential

Answer 16

chemical and electrical gradients balanced

Question 17

gated ion channels

Answer 17

neuron channels that respond to some stimulus by opening/closing

Question 18

voltage-gated ion channels

Answer 18

respond to change in membrane potential

Question 19

depolarization

Answer 19

membrane potential becomes less negative and activates voltage-gated Na+ channels

Question 20

action potential

Answer 20

massive, rapid depolarization; once potential exceeds threshold of -55mV; all or nothing response

Question 21

hyperpolarization

Answer 21

a change in a cell’s membrane potential that makes it more negative

Question 22

action potential steps

Answer 22

gated Na+ channels only active for a short time, rapid depolarization opens voltage-gated K+ channels resulting in hyperpolarization, undershoots normal resting rate

Question 23

refractory period

Answer 23

time between action potentials; sets maximum frequency of action potentials

Question 24

myelin sheath

Answer 24

protective membrane around axon, made up of glial cells

Question 25

oligodendrocytes

Answer 25

glial cells in CNS

Question 26

schwann cells

Answer 26

glial cells in PNS

Question 27

factors that increase speed of propagation

Answer 27

axon diameter and insulation

Question 28

nodes of Ranvier

Answer 28

gaps in myelin sheath; voltage gated Na+ channels limited to

Question 29

synaptic cleft

Answer 29

space between presynaptic and postsynaptic cells

Question 30

ligand-gated ion channel

Answer 30

bind neurotransmitter on postsynaptic membrane

Question 31

excitatory postsynaptic potentials

Answer 31

depolarize membrane

Question 32

inhibitory postsynaptic potentials

Answer 32

hyperpolarize membrane

Question 33

temporal summation

Answer 33

series of potentials from same synapse (graded)

Question 34

spatial summation

Answer 34

potentials from different synapse (graded)

Question 35

nerve net

Answer 35

nervous system of cnidarians

Question 36

nerves

Answer 36

multiple neurons; found in more complex animals

Question 37

central nervous system (CNS)

Answer 37

brain + nerve cords running body length

Question 38

cephalization

Answer 38

concentration of nervous system into the brain

Question 39

peripheral nervous system (PNS)

Answer 39

ganglia and nerves outside CNS

Question 40

ganglia

Answer 40

cell bodies; groups of nerves or brain cells that are closely related

Question 41

brain

Answer 41

where all stimulus, voluntary and involuntary behavior is processed

Question 42

spinal cord

Answer 42

carries impulses to and from brain

Question 43

reflexes

Answer 43

involuntary movement

Question 44

gray matter

Answer 44

non-myelin matter, outside of brain

Question 45

white matter

Answer 45

myelin matter, inside of brain, outside of spinal cord

Question 46

derived from hollow dorsal nerve cord

Answer 46

central canal (spinal cord) and ventricles (brain); filled with cerebrospinal fluid for diffusion of resources and waste

Question 47

blood-brain barrier

Answer 47

selective, semi-permeable membrane between the blood and the interstitium of the brain

Question 48

glia

Answer 48

nourish, support, and regulate the functioning of neurons in the vertebrate brain and spinal cord

Question 49

radial glia

Answer 49

embryonic glia that form tracks along which newly formed neurons migrate from the neural tube, the structure that gives rise to the CNS

Question 50

astrocytes

Answer 50

facilitate information transfer at synapses and sometimes release neurotransmitters; initiates formation of the blood-brain barrier during embryonic development

Question 51

radial glia and astrocytes

Answer 51

can act as stem cells, generating new neurons in glia

Question 52

microglia

Answer 52

immune cells that protect against pathogens

Question 53

ependymal cells

Answer 53

line ventricles and promote circulation of cerebrospinal fluid

Question 54

cranial nerves

Answer 54

connect brain with head

Question 55

spinal nerves

Answer 55

connect spinal cord to rest of body

Question 56

afferent neurons

Answer 56

bring information to the CNS (sensory)

Question 57

efferent neurons

Answer 57

carry information from CNS

Question 58

motor system

Answer 58

skeletal muscles; voluntary and reflex motion

Question 59

autonomic nervous system

Answer 59

involuntary; smooth and cardiac muscle, glands, etc.

Question 60

sympathetic division

Answer 60

arousal, "fight or flight"

Question 61

parasympathetic division

Answer 61

calming, "rest and digest"

Question 62

enteric division

Answer 62

digestion

Question 63

brainstem

Answer 63

midbrain + pons + medulla; homeostasis, coordination of movement, attention, alertness, motivation

Question 64

cerebellum

Answer 64

coordinates movement, hand-eye coordination

Question 65

forebrain

Answer 65

diencephalon and cerebrum

Question 66

diencephalon

Answer 66

thalamus, hypothalamus and epithalamus; homeostasis, sensory info, circadian rhythms

Question 67

cerebrum

Answer 67

center for information processing in mammals

Question 68

corpus callosum

Answer 68

connect the left and right hemispheres

Question 69

reticular formation

Answer 69

controls sleep and arousal; filters incoming information and determines what reaches the cerebral cortex

Question 70

biological clock

Answer 70

regulates sleep cycles

Question 71

limbic system

Answer 71

responsible for emotions; amygdala, hippocampus, and thalamus

Question 72

cortex

Answer 72

frontal, parietal, occipital and temporal lobes (each with different functions)

Question 73

laterilization

Answer 73

two hemispheres not identical in function

Question 74

neural plasticity

Answer 74

learning and memory formed by strengthening or weakening of synaptic connections

Question 75

hippocampus

Answer 75

form memories by rearranging connections

Question 76

short term memories

Answer 76

store stimuli for a short time

Question 77

long-term memories

Answer 77

rearrangements in the cerebral cortex

Question 78

long term potentiation

Answer 78

frequent excitation of a synapse can make the postsynaptic neuron more sensitive to the presynaptic neuron