Regarding the neuromuscular junction...
a. Depolarization of the presynaptic membrane directly causes voltage-gated calcium channels in the membrane to open.
b. Action potentials in the sarcolemma directly cause calcium channels to open.
c. Action potentials in the sarcoplasmic reticulum indirectly cause the calcium ATPase pump to function, if ATP is present.
d. both a) and b) are correct, and c) is incorrect
e. a), b) and c) are all correct
2)
Following ATP hydrolysis by myosin, which steps occur during one cross-bridge cycle?
a. |
Myosin is activated; if calcium is present in the sarcoplasm, then myosin binds to actin; inorganic phosphate dissociates from myosin. |
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b. |
Myosin is activated; if calcium is present in the sarcoplasm, then the conformation of troponin and tropomyosin changes; calcium ATPase pumps calcium into sarcoplasmic reticulum. |
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c. |
Myosin is activated; if calcium is not present in the sarcoplasm, then ADP and inorganic phosphate dissociate from myosin; troponin and tropomyosin remain bound to actin, covering the myosin binding site. |
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d. |
both a) and b) are correct, and c) is incorrect |
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e. |
a), b) and c) are all correct |
5 points
1 Ans: The correct option is E (All a, b and c are correct options)
The plasma membrane of the muscle cell is sarcolemma. Excitation of the sarcolemma induces the release of Ca2+ ion from the sarcoplasmic reticulum. Sarcoplasmic reticulum have ATP pump in its membrane and calcium ion is pumped back in the sarcoplasmic reticulum in presence of ATP, causing muscle to relax.
Regarding the neuromuscular junction... a. Depolarization of the presynaptic membrane directly causes voltage-gated calcium channels in...
Question 28 4 pts Once the action potential occurs in the sarcolemma, it spreads moving down the T-tubules. What next? What is the correct order of events which result in skeletal muscle contraction? (4 points) a. Once the muscle cell action potential is initiated then calcium ions are released from the sarcoplasmic reticulum. These calcium ions bind to troponin. With this binding, tropomyosin is pulled away from the active sites on actin. Myosin can bind with actin forming a cross...
QUESTION 7 What happens (immediately) if T-tubules blocked in skeletal muscle action potential increased an action potential blocked from progressing in fibril Myosin phosphatase in muscle O4(MP) activated d. inactivated QUESTION 8 Can be activated by stretch receptors (best answer only) a. Skeletal muscle Ob. smooth muscle Oc. myosin light chain phosphataso Od. A and B QUESTION 9 Action potential leads to activation of neurotransmitter in muscle answer true or false a true b. false c. not sure od silly...
causes the sarcoplasmic retieatum of skeletal musele cells to release calcium onto the sarcomere: what he movement of tropomyosin off of the binding site of actin the binding of acetyleholine with its receptor the binding of caleium with troponin he movement of the action potential down the T-tubal the binding of ATP to the Ca-ATPase on the sarcoplasmic reticulum "Rigor Mortis" is caused b a. the inability of the myosin head to detach from actin b. a lack of calcium...
13. During skeletal musele contraction, whet substance does the sarcoplasmic reticulum store and release? A. acetyicholine B. sodium D. calcium 34. What stimalates the sarcoplasmic reticulum (SR) to release this chemical? A. the voltage change from the muscular action potential traveling down the transverse (1) tubules B. the binding of acetylcholine to ligand-gated channels in the transverse tubules C. direct stimulus from the neural action potential D, the binding of myosin to actin 35. Transverse (T) tubales are extensions of...
B C). F Fotch G I Anind A [Choose) B [Choose ] Acetyl-choline gated sodium channels open, causing a graded potential on the sarcolemma An action potential moves across the sarcolemma and down the t-tubules An action potential arrives in the muscle cell via gap junctions The calcium ATPase is always active Ca++ is released from the sarcoplasmic reticulum through the opening of voltage gated calcium channels (DHP- Calcium diffuses through the cytosol and binds with troponin Acetylcholine binds with...
1.During skeletal muscle contraction, the following occurs except A)ATP hydrolysis directly causes the movement of the myosin head to cause a power stroke B)When the myosin head releases a phosphate, it can bind actin C)When a new ATP binds to a myosin head, it releases actin D)ATP hydrolysis activates the myosin head so it can bind actin E)When the myosin head binding actin releases ADP, it moves to create the power stroke 2.During skeletal muscle contraction, the length of the...
efer Figure2 to answer questions 18-21: 8. produce the myelin sheaths of neurons in the central Figure 2 nervous system. 19 form the Blood Brain Barrier 20._ are responsible for neurotransmitter release. 21 have ligand gated ion channels that are activated by neurotransmitters 22. Functionally, which cellular location is the neuron's "decision- making site" as to whether or not an action potential will be initiated? A axonal membrane B. axon hillock C. dendritic membrane D. presynaptic membrane 23. Calcium and...
Chapters 6-8: Muscle and Neuromuscular Junction 1 Myofibrils A Excitatory transmitter that excites muscle fiber membrane 2 Titin B Required to cause smooth muscle relaxation 3 Actin filaments C Thousands grouped together to form the muscle fiber 4 Tropomyosin D Nerve fiber sympase at muscle fiber 5 Sarcomere E Block active sites on actin filaments to block myosin attraction Acetylcholine F activates myosin cross-bridges in smooth muscle 7 Neuromuscular junction G Muscle sections between Z discs that individually contract 8...
Directly responsible for the power stroke associated with contraction Release of O a Natt release of Phosphate and ADP from myosin Dhead o Binding of binding of Phosphate and ADP to actin d, head QUESTION 16 Can lead to muscle atrophy a. Limb cast b. space flight Oc.sedentary life style d. all of above QUESTION 17 Highest concentration of Car+ voltage gated channels in which a cardiac caveolae b. skeletal muscle s intercalated disk d. Smooth muscle QUESTION 18 Muscle...
change pas channels in the volta t ive protein to change shape. This A of the S l e terminal siste oplasmic reticum calcio p r eneule warcoplasm reticulum sodium ions m o nster transverse tubules sarcolemma: calcium ions Saroplasmic reticum: triadsarcolemma: calcium ions sons bind to This causes a change in shape and exposing C D E Calcium vesicle tylcholine action potential Sodium sarcolemma calcium on myosin heads Sodium sacoplasmic reticulum calcium ions actin 15. An attaches to exposed...