Contraction of the muscle Fiber

Question 1

The 3 structures that are directly controlling the muscle contraction

Answer 1

Muscle
Nerve
Synapse

Question 2

Theory stating that muscle contraction is based on shortening of sarcomeres throughout the skeletal muscle. Because sarcomeres are end to end, all the way down the length of the skeletal muscle cell, the muscle cell shortens too.

Answer 2

Huxley’s Sliding Filament Theory

Question 3

Huxley’s Sliding Filament Theory predicts that thick and thin filaments must overlap and slide past one another. Greater overlap = shorter or longer muscle?

Answer 3

Shorter Muscle

Question 4

Contractile element that is made of myosin that has hinged tail and 2 heads which are capable of flexing

Answer 4

Thick Filament

Question 5

What two binding sites are on the heads of myosin?

Answer 5

ATP and Actin binding sites

Question 6

Name the 3 components of thin filament

Answer 6

Actin
Tropomyosin
Troponin Complex

Question 7

There is a binding site on the actin molecules for

Answer 7

myosin

Question 8

Two additional things that are necessary for contraction to occur

Answer 8

Calcium Ions

ATP

Question 9

When a muscle is relaxed, is there maximal or minimal filament overlap?

Is there action potential from the nerve?

Answer 9

Minimal

No.

Question 10

“Activated” myosin heads are holding…

Answer 10

ADP and inorganic phosphate after hydrolization from ATP

Question 11

Is the ATP kinetic or potential energy?

Answer 11

Potential

Question 12

Is there Ca in the cytoplasm surrounding microfibrils?

Answer 12

No

Question 13

Where does the Calcium come from?

Answer 13

Terminal cisternae of the sarcolplasmic reticulum

Question 14

What causes the calclium to enter the cytoplasm and surround the myofibrils?

Answer 14

Action potential along the nerve

Question 15

What does Ca bind with in the myofibril?

Answer 15

Troponin

Question 16

What happens to the troponin once Ca binds with it?

Answer 16

It changes shape

Question 17

What is troponin attached to?

Answer 17

Tropomyosin

Question 18

What forms when the myosin (charged) binds to actin (thick and thin filament of myosin head binds to actin)

Answer 18

Cross Bridge Attachment

Question 19

Flexion of myosin head an tail that pulls thin filament along after cross bridge attachment

Answer 19

Power Stroke

Question 20

What happens when the power stroke goes on the entire sarcomere?

Answer 20

Sarcomere Shortening

Question 21

What occurs next, a process that requires ATP binding to the myosin head?

Answer 21

Cross Bridge Detachment

Question 22

Where does ATP come from?

Answer 22

Cytoplasm

Question 23

What cleaves the ATP into ADP and inorganic phosphate?

Answer 23

Myosin ATPase

Question 24

What does cleaving of ATP into ADP by myosin ATPase achieve?

Answer 24

Storage of the potential energy in the myosin head for next cross bridge

Question 25

What if there is no more contraction/action potential to occur?

Answer 25

Returns to relaxed state

Question 26

What happens to Ca and ATP if there is no more contraction to occur

Answer 26

Calcium goes to terminal cysternae | ATP be bound to myosin head

Question 27

Which step of sarcomere shortening actually uses ATP?

Answer 27

Power stroke

Question 28

Structure that tells the muscle what to do and when to do it

Answer 28

Motor nerve

Question 29

Axon of nerve comes from spinal chord and expands into three

Answer 29

terminal boutons

Question 30

Terminal bouton contains these, which are contained within it

Answer 30

Synaptic Vesicles

Question 31

Neurotransmitter which functions as ligand within terminal bouton

Answer 31

Acetylcholine

Question 32

Channels in terminal bouton in addition to typical Na and ATPase channels (maintenance proteins)

Answer 32

Ca channels

Question 33

Muscle side of neuromuscular junction that contains sarcolemma is called

Answer 33

Motor End Plate

Question 34

What formation occurs on the motor end plate to increase surface area?

Answer 34

Junctional Folds

Question 35

Within junctional folds are receptors for acetylcholine

Answer 35

Ach Receptors

Question 36

The space between the nerve and muscle that has glycoproteins to hold structures in place

Answer 36

Synaptic Cleft

Question 37

Action potential causes what to change in the plasma membrane of the terminal bouton

Answer 37

Voltage Change

Question 38

The voltage change causes opening of which voltage gated channels to allow its movement from outside bouton to inside the bouton?

Answer 38

Calcium Voltage Gated Channels

Question 39

What does the calcium cause when its released in the terminal bouton?

Answer 39

Vesicle migration

Question 40

When vesicles reach end of terminal boutons, what occurs?

Answer 40

Exocytosis of acetocholyne

Question 41

Acetylcholine crosses the synapse and binds with what on the motor end plate?

Answer 41

Receptors

Question 42

What does acetycholine migration across the membrane cause?

Answer 42

Graded potential (Na+ flows in)

Question 43

What follows the graded potential?

Answer 43

Action potential along membrane of skeletal muscle

Question 44

How is acetylcholine removed to stop action potentials from recurring?

Answer 44

Acetylcholinesterase

Question 45

Means when you excite the cell a contraction will follow

Answer 45

Excitation-Contraction Coupling

Question 46

What structure of muscle cell is exciteable and brings the action potential to the muscle fibers?

Answer 46

T-tubules

Question 47

What is released after excitation of t-tubules?

Answer 47

Calclium voltage gated channels in terminal cysternae open and Ca diffuses