Physiology of a muscle contraction

Question 1

thin filament slide inward past thick myosin filament

Answer 1

Sliding Filament mechanism

Question 2

convert nervous signal to a muscle signal

Answer 2

Excitation

Question 3

muscle action potential spreads through the T-Tubules into sarcoplasm

Answer 3

Excitation-Contraction Coupling

Question 4

get calcium out of Sarcoplasm back into SR

Answer 4

Relaxation

Question 5

Synapitc Knob stops releasing acetylcholine

Answer 5

Relaxation

Question 6

sarcomere shortens but neither thin or thick filament change length

Answer 6

Sliding Filament Mechanism

Question 7

nervouse signal arrives at a synaptic knob

Answer 7

Excitation

Question 8

When nerve signals no longer arrive at the neuromuscular junctions

Answer 8

Relaxation

Question 9

Calcium release channels into ST open

Answer 9

Excitation-Contraction coupling

Question 10

ATP attach to ATP binding site on myosin head

Answer 10

Sliding filament mechanism

Question 11

causes channels to open, allows calcium ions to enter synaptic knob

Answer 11

Excitation

Question 12

nerve signals are no longer transferred to the motor end plate

Answer 12

relaxation

Question 13

Calcium ions diffuse into sarcoplasm within one millisecond

Answer 13

Excitation contraction coupling

Question 14

ATP splits by myosin ATPase and energizes their myosin head

Answer 14

sliding filament mechanism

Question 15

triggers exocytosis of synapitc vesicles release acetylchonline diffuses the synaptic cleft

Answer 15

excitation

Question 16

calcium channels close

Answer 16

Relaxation

Question 17

Calcium ion bind to troponin molecules on thin filaments causing them to change shape

Answer 17

excitation contraction coupling

Question 18

energizes myosin head attaches to an actin binding site to form across bridge.

Answer 18

sliding filament mechanism

Question 19

acetylcholinesterase enzyme breaks acetylcholine molecule into fragments that are absorbed into the synaptic knob

Answer 19

Relaxation

Question 20

acetylcholine binds to receptors on the motor neuron and plate, causes them to change shape.

Answer 20

excitation

Question 21

myosin head swivels toward the center of the sacromere

Answer 21

sliding filament mechanism

Question 22

troponin-tropomyosin complex shift to new position

Answer 22

excitation contraction coupling

Question 23

Calcium ions transport out the sarcoplasm and break into SR using ATP energy

Answer 23

relaxation

Question 24

Calcium ions bind to protein calsequestrin

Answer 24

Relaxation

Question 25

Ion channels open and sodium ions enter muscle fiber while potassium ions leave muscle fiber

Answer 25

Excitation

Question 26

Calcium ions dissociates from troponin and troponin-tropomyosin complex moves back to original postition

Answer 26

relaxation

Question 27

exposes the myosin-binding sites on the actin filament so cross-bridge might form

Answer 27

excitation contraction coupling

Question 28

myosin head draws the thin filament past the thick filament to generate power-stroke

Answer 28

sliding filament mechanism

Question 29

move ions across sarcolemma creates muscle action potential excites muscle fiber

Answer 29

excitation

Question 30

2nd molecule of ATP attaches to the ATP binding site on the myosin head and allows ATP to detach the actin filament

Answer 30

sliding filament mechanism

Question 31

calcium concentration in sarcoplasm kept low unless contraction muscle fiber

Answer 31

relaxation.

Question 32

new cross bridge forms along the thin filament and generates another power stroke.

Answer 32

sliding filament mechanism.

Question 33

Free phosphate group immediately bind with calcium ion in sarcoplasm

Answer 33

relaxation

Question 34

repeat as long as ATP and calcium present

Answer 34

sliding filament mechanism