chapter 48

Question 1

what are neurons?

Answer 1

the nerve cells that transfer information within the body

Question 2

what is the significance if the cell body?

Answer 2

is where most of the organelles are located

Question 3

what are dendrites?

Answer 3

highly branched extensions of a neuron

Question 4

what is an axon?

Answer 4

an extension that transmits signals to other cells

Question 5

what is an axon hillock?

Answer 5

cone shaped base of an axon, where signals travel down

Question 6

what is a synapse?

Answer 6

a junction between cells

Question 7

what is the synaptic terminal?

Answer 7

the part of each axon branch that forms a specialized junction

Question 8

what are neurotransmitters?

Answer 8

chemical messengers

Question 9

what is a presynaptic cell?

Answer 9

neuron where info is coming from

Question 10

what is a postsynaptic cell?

Answer 10

gland/muscle where info is going to

Question 11

long distance transfer is

Answer 11

electric

Question 12

short distance transfer is

Answer 12

chemical

Question 13

what is the glia?

Answer 13

surround neuron, regulate fluid, most abundant cell type in central nervous system

Question 14

what are the 3 stages of information processing?

Answer 14

sensory input, integration, and motor output

Question 15

what are sensory neurons?

Answer 15

transmit information about external stimuli

Question 16

what are interneurons?

Answer 16

form the local circuits connecting neurons in the brain

Question 17

what are motor neurons?

Answer 17

transmit signals to muscle cells, causing them to contract

Question 18

what s the central nervous system?

Answer 18

neurons that carry out integration

Question 19

what is the peripheral nervous system?

Answer 19

neurons that carry information into and out of the CNS

Question 20

what is membrane potential?

Answer 20

ions are unequally distributed causing the cell to be negatively charged. attraction of opposite charges across the plasma membrane is a source of potential energy

Question 21

what is resting potential?

Answer 21

potential of a neuron that is not sending a signal

Question 22

what is a sodium-potassium pump?

Answer 22

uses ATP hydrolysis to actively transport sodium out of the cell and potassium into the cell. generates a net export of positive charge.

Question 23

why are sodium and potassium important in resting potential?

Answer 23

ions each have a concentration gradient across the plasma membrane of a neuron

Question 24

what are gated ion channels?

Answer 24

ion channels that open/close in response to stimuli

Question 25

what are the 3 types of gated ion channels?

Answer 25

chemical, mechanical, and voltage

Question 26

what is hyperpolarization?

Answer 26

increased magnitude of the membrane potential that makes the membrane more negative

Question 27

how does hyperpolarization work?

Answer 27

ions flow across membrane trough gated ion channels (potassium channels)

Question 28

what is depolarization?

Answer 28

a reduction in the magnitude of the membrane potential, makes the inside less negative (sodium channels)

Question 29

what is the refractory period?

Answer 29

recovery time for membrane to be ready for the next stimulus

Question 30

what is a graded potential?

Answer 30

de/hyper polarization depends on strength of stimulus. amp is correlated to how powerful the stimulus is

Question 31

what is an action potential?

Answer 31

always leads to depolarization, massive change in membrane voltage. can regenerate, god for long distance signals

Question 32

how is action potential positive feedback?

Answer 32

sodium makes more channels to open

Question 33

what is a threshold?

Answer 33

when depolarization increases the membrane voltage to a particular value

Question 34

what is epilepsy?

Answer 34

affects sodium channels in brain makes nerves fire too much-> channels overexcited

Question 35

how is width of the axon related to the speed of action potential?

Answer 35

more width, more speed

Question 36

rate of conduction of action potential governs what?

Answer 36

speed of an animals response

Question 37

what is the myelin sheaths?

Answer 37

electrical insulation that surrounds vertebrate axons

Question 38

what are oligodendrocytes?

Answer 38

glia that produced myelin sheaths in CNS

Question 39

what are schwann cells?

Answer 39

glia that produces myelin sheaths in the PNS

Question 40

what are the nodes of ranvier?

Answer 40

voltage-gated sodium channels restricted to gaps in the myelin sheaths

Question 41

what is multiple sclerosis?

Answer 41

autoimmune disease degrading myelin sheets

Question 42

what is guillain-barre syndrone?

Answer 42

damages nerve cells, death from lack of air.

Question 43

what is X-ALD?

Answer 43

geenetic disease where myelin sheets don't develop

Question 44

what is progressive multifocal leukoencephalopathy?

Answer 44

virus, possibly fatal

Question 45

what is central pontine myelinolysis?

Answer 45

damage in myelin sheaths in brain, caused by diet, sodium levels decrease

Question 46

what are electrical synapses?

Answer 46

synapses that contain gap junstions that allow electrical current to flow directly from 1 neuron to another

Question 47

what are chemical synapses?

Answer 47

involve the release of a chemical neutotransmitter by the presynaptic neuron

Question 48

what is the presynaptic neuron?

Answer 48

releases chemical neurotransmitter

Question 49

what are synaptic vesicles?

Answer 49

packages ofneutrotransmitter in multiple membrane-encolsed compartments

Question 50

what are synaptic clefts?

Answer 50

separates pre/post synaptic cell

Question 51

what does signaling depend on?

Answer 51

type of neurotransmitter released at the presynaptic and the receptor produced at the postsynaptic membrane

Question 52

when does a signal end?

Answer 52

when the neurotransmitter is cleared from the synaptic cleft

Question 53

what is acetylcholine?

Answer 53

triggers voluntary muscle contractions, heartbeat, and excretion of certain hormones. found in CNS and PNS. many toxins affect it, change its transmission by inactivating/ hyperactivating muscles

Question 54

what is glutamate?

Answer 54

the neurotransmitter at the neuromuscular junction in invertebrates

Question 55

what is GABA?

Answer 55

mood modulator, blocks nerve impulses in the brain, works opposite of glutamate, tells cells not to fire. low levels cause cells to get overexcited.

Question 56

what is valium?

Answer 56

brings GABA back into brain

Question 57

what are biogenic animes?

Answer 57

neurotransmitters synthesized from amino acids

Question 58

what is dopamine?

Answer 58

both excitatory and inhibitory neurotransmitter

Question 59

what is seratonin?

Answer 59

inhibitory, regulates mood

Question 60

what is epinephrine?

Answer 60

fight or flight hormone, produced in adrenal gland ,

Question 61

what is norepinephrine?

Answer 61

noaderenaline

Question 62

what are neuropeptides (endorphins) ?

Answer 62

natural pain relievers

Question 63

what role does carbon monoxide play in neurotrasmitters?

Answer 63

regulates the release of hormones from hypothalamus