AP test 3

Question 1

(suprathreshold) action potential is always:

Answer 1

all or none

Question 2

when voltage gated reaches threshold

Answer 2

sodium goes in with gradient and cell becomes more positive

Question 3

in repolarization potassium..

Answer 3

goes out (with its gradient)

Question 4

during action potential:

Answer 4

all leak channels stay open, Na+/K+ pump continues working

Question 5

during the peak phase:

Answer 5

voltage gated potassium channels open
voltage gated sodium channels inactivated
absolute refractory period

Question 6

absolute refractory period (during peak phase)

Answer 6

neuron cannot generate any more action potentials

Question 7

repolarization phase:

Answer 7

reduced influx of sodium
voltage gated potassium channels remain open- potassium leaves the cell

Question 8

hyperpolarization phase:

Answer 8

voltage gated potassium channels remain open
inactivation of voltage gated sodium channels opens
relative refractory period

Question 9

relative refractory period(hyperpolarization phase)

Answer 9

channels can still open but need a bigger stimulus than at rest

Question 10

after the hyperpolarization:

Answer 10

only 1 out of every 100,000 potassium must leave to lower the membrane potential; the overall concentrations of potassium and sodium do not change during action potential

Question 11

what is the voltage value for sodium at the voltage gated channnel

Answer 11

-55mV

Question 12

after hyperpolarization

Answer 12

voltage gated potassium channels close, membrane potential returns to resting value

Question 13

action potential propagation:

Answer 13

voltage gated channels open, sodium follows gradient goes in- ions diffuse away from point of entry

Question 14

action potential propagation- if enough sodium diffuse in -

Answer 14

next segment of voltage gated channels open (positive feedback)

Question 15

oligodendrocytes

Answer 15

branches and wraps a cell in myelin- produces myelin in CNS

Question 16

Schwann cells

Answer 16

make myelin in PNS

Question 17

nodes of ranvier

Answer 17

gaps between Schwann cells; voltage gated sodium channels are present

Question 18

saltatory conduction

Answer 18

jumping from node to node

Question 19

larger the diameter of the axon the ___ __

Answer 19

faster the impulse will go

Question 20

what two things increase impulse conduction

Answer 20

axon diameter, myelination

Question 21

Synaptic transmission-

Answer 21

neurotransmitter released via exocytosis from presynaptic neuron
-neurotransmitter binds to receptor on post synaptic cell
neurotransmitter changes the permeability of post synaptic cell’s membrane

Question 22

voltage gated calcium channels

Answer 22

in the synaptic knob- moves into pre synaptic knob

Question 23

neurotransmitter

Answer 23

made in ER then modified and packaged in Golgi apparatus to vesicles, then transported to synaptic knob where it hangs out then opens up and allows neurotransmitters out

Question 24

after the neurotransmitter has been let out it binds to the receptor

Answer 24

ligand gated ion channels in post synaptic cells

Question 25

fate of neurotransmitters

Answer 25

enzymatically destroyed- change in a way that it can't interact with post synaptic cell reuptake into axon terminal by transport proteins- retook by presynaptic cell

Question 26

electric synapses-

Answer 26

cardiac and smooth muscle; ion currents flow via gap junctions

Question 27

motor neurons leave the central nervous system and have an ___. The group is called __ __

Answer 27

effect, motor unit

Question 28

Skeletal muscle structure

Answer 28

epimysium, perimysium, endomysium, tendons and aponeuroses

Question 29

epimysium bundles together___. perimysium surrounds each ___. endomysium surrounds each muscle ___

Answer 29

fascicle, fascicle, cell

Question 30

tendons vs aponeuroses

Answer 30

tendons come to more of a bump, aponeuroses are more sheet

Question 31

sarcolemma

Answer 31

cell membrane of skeletal muscle fiber

Question 32

sarcoplasm

Answer 32

cytoplasm of muscle cells

Question 33

mutlinucleate

Answer 33

myoblasts fuse to form myocytes

Question 34

myofibrils

Answer 34

made up of filaments (actin, myosin)--contractile proteins

Question 35

what makes up the thick and thin filaments-

Answer 35

thick-myosin thin-actin

Question 36

sarcomeres-

Answer 36

smallest functional part of a skeletal muscle... composed of actin and myosin

Question 37

M-line

Answer 37

filaments in the middle hold together myosin

Question 38

A-band

Answer 38

runs entire length of thick filament

Question 39

Z-lines

Answer 39

zig zag

Question 40

I band

Answer 40

only the thin filament

Question 41

H-zone

Answer 41

only the myosin

Question 42

tropomyosin and troponin are on what filament

Answer 42

thin

Question 43

tropomyosin

Answer 43

surrounds the tropinin

Question 44

tropinin

Answer 44

moves tropomyosin out of the way so myosin can bind to actin

Question 45

sarcoplasmic reticulum

Answer 45

stores calcium, surrounds each myofibril

Question 46

transverse tubules

Answer 46

opening that pushes deeper into muscle, wraps around sarcoplasmic reticulum

Question 47

terminal cisternae

Answer 47

one on each side of transverse tubule, where calcium gets collected

Question 48

triad

Answer 48

where thick and thin filaments overlap, primarily where calcium releases

Question 49

motor units

Answer 49

motor neuron and all skeletal muscle it talks to

Question 50

motor neuron

Answer 50

talks to a couple dozen to maybe a couple hundred skeletal muscle fibers

Question 51

what is the neuromuscular junction

Answer 51

where the neuron meets the skeletal muscle fiber (chemical synapse) (excitatory)

Question 52

Motor end plate

Answer 52

specialized region part of the skeletal muscle fiber where the neuromuscular junction is (ligand gated channels)

Question 53

Stimulus for contraction (1)

Answer 53

1. Release of acetylcholine- action potential gets to synaptic knob. opens voltage gated calcium channels. causes Ach to be released.

Question 54

Stimulus for contraction 2)

Answer 54

end plate potential and muscle action potential- ligand binds to ligand gated sodium channels. sodium comes into the cells

Question 55

Stimulus for contraction (3)

Answer 55

calcium released from SR- action potential travels down sarcolemma goes into transverse tubules bring SR to threshold opens voltage gated Ca2+, and calcium goes out (follows gradient)

Question 56

sliding filament model

Answer 56

myofilaments do not change size, sarcomeres shorten, areas of actin/myosin overlap increase

Question 57

excitation-contraction coupling

Answer 57

motor neuron releases Ach, ligand gated channels on sarcolemma open, Na+ and K+ channels open, end plate potential results, threshold achieved, voltage gated Na+ channels open, sarcolemma and t-tubules depolarize

Question 58

cross bridge cycling

Answer 58

ATP binds to myosin, hydrolyzes activated myosin binds to actin energy released during power stroke hydrolysis of ATP cross bridge cycle repeats

Question 59

in order for relaxation to occur

Answer 59

stop releasing ACh --calcium pumped back into the SR binding sites now blocked sarcomere returns to original length

Question 60

what is rigor mortis

Answer 60

calcium still gets out of the SR, crossbridge is still available but no ATP to break the crossbridge