Human Physiology Test Bank 3 115+ Multiple
Choice Questions And Bond Italic Answers And
Italic Explanations 2026/2027 (100% Verified
Answers) Update
(one best answer) When Dr. Merriman talks about Ca++ "providing permission to slide", she means that:
A) Ca++ influx from the ISF depolarizes the skeletal muscle cell, initiating contraction
B) Ca++ binding changes the shape of the myosin "hands" so they can grab the actin
C) Ca++ binding changes the shape of a protein that is blocking myosin's access to actin - ✅🌹CORRECT
ANSWER-C) Ca++ binding changes the shape of a protein that is blocking myosin's access to actin
one best answer) When skeletal muscle cells shorten, what actually gets shorter?
A) Actin filaments
B) Myosin filaments
C) Sarcomeres
D) Sarcoplasmic reticulum - ✅🌹 CORRECT ANSWER-C) Sarcomeres
(all that apply) What role(s) does ATP play in skeletal muscle contraction?
A) It powers AT Pase pumps that push Ca++ back into the sarcoplasmic reticulum
B) It powers AT Pase pumps that push Ca++ back into the interstitial fluid
C) It powers the pulling action of the myosin "hands" that in turn slides the actin filament
D) It enables the myosin "hands" to let go of actin and reposition themselves for another slide -
✅🌹CORRECT ANSWER-A) It powers ATPase pumps that push Ca++ back into the sarcoplasmic reticulum
C) It powers the pulling action of the myosin "hands" that, in turn, slides the actin filament
,(one best answer) Which of the following is the best summary of the skeletal muscle stretch reflex?
A) It ensures that skeletal muscle cells relax and lengthen enough that sarcomere sliding filaments can
no longer touch each other, saving the relaxing cell some ATP
B) It helps keep sarcomere sliding filaments overlapping just enough to be able to shorten when
commanded to do so by Ca++
C) It rapidly shortens sarcomere sliding filaments to the point that they completely overlap and have
generated maximal tension/force - ✅🌹CORRECT ANSWER-B) It helps keep sarcomere sliding filaments
overlapping just enough to be able to shorten when commanded to do so by Ca++
What is the cytoplasmic molecule that skeletal muscle (and, as it turns out, cardiac muscle) has that
helps it have as good an oxygen supply as possible, even during extreme physical exertion?
________________________________ - ✅🌹CORRECT ANSWER-myoglobin
What is the cytoplasmic molecule that skeletal muscle (and, as it turns out,cardiac muscle) has that
helps it have as good a glucose supply as possible, even duringextreme physical exertion?
_____________________________ - ✅🌹CORRECT ANSWER-glycogen
Which of the following ATP-regenerating reactions within the muscle do NOT require O2 to occur?
A) Cori Cycle
B) Creatine phosphate dephosphorylation (loss of its phosphate)
C) Electron Transport Chain
D) Glycolysis
E) Krebs Cycle - ✅🌹CORRECT ANSWER-B) Creatine phosphate dephosphorylation (loss of its phosphate)
D) Glycolysis
all that apply) Which of the following are molecules found in abundance within skeletal
musclecytoplasm as adaptations to power contraction even in times of low plasma pO2?
A) Cori Cycle
B) Creatine
C) Creatinine
D) Glycogen
,E) Myoglobin
F) Triglycerides - ✅🌹CORRECT ANSWER-D) Glycogen
E) Myoglobin
When skeletal muscle ismaximally active, the organ called the ________________ accepts lactate waste
dumped intothe blood by the skeletal muscle, converts it back to _____________________, and sends
itback to the skeletal muscle by way of the _______________________. This process is calledthe
__________ __________. - ✅🌹CORRECT ANSWER-Liver
Glucose
Bloodstream
Cori Cycle
Creatine is a nitrogenous molecule made in the ___________________ and transported to the skeletal
muscle via the__________________. When taken up by skeletal muscle cells, MOST creatine is
converted to _______________________ that then serves as a quick way to regenerate ATP by donating
its phosphate group to creatine. A TINY proportion of skeletal muscle creatine is converted to the waste
form known as ____________________ and lost in the urine - ✅🌹CORRECT ANSWER-liver
bloodstream
phosphocreatine (or creatine phosphate)
creatinine
WhatTWO (2) types of fuel molecules does skeletal muscle store for its own use? - ✅🌹CORRECT
ANSWER-Glycogen, Triglycerides
(one best answer) As skeletal muscle's "oxygen debt" is repaid by re-establishing the normalplasma pO2
and reloading O2-binding proteins with O2, which ONE of the following ATP-regenerating pathways is
"reactivated" FIRST?
A) Anaerobic fermentation in the cytoplasm
B) Creatine phosphate in the cytoplasm
C) Glycolysis in the cytoplasm
D) Krebs Cycle in the mitochondria
, E) Electron transport chain in the mitochondria - ✅🌹CORRECT ANSWER-B) Creatine phosphate in the
cytoplasm
(all that apply) Which are features of the action potential depolarization observed in pacemaker cardiac
muscle cells?
A) These APs are triggered by APs transferred by pacemaker or conduction system cellswithin the heart
B) These APs arise spontaneously.
C) These APs depend on voltage-gated sodium channels.
D) These APs depend on voltage-gated potassium channels.
E) These APs depend on voltage-gated calcium channels.
F) These APs never truly return to Vrest - ✅🌹CORRECT ANSWER-B) These APs arise spontaneously
E) These APs depend on voltage-gated calcium channels
A) These APs are triggered by APs transferred by pacemaker or conduction system cells within the heart
all that apply) Which are features of the action potential depolarization observed in contractilecardiac
muscle cells?
A) These APs are triggered by APs transferred by pacemaker or conduction system cellswithin the heart.
B) These APs arise spontaneously.
C) These APs depend on voltage-gated sodium channels.
D) These APs depend on voltage-gated potassium channels.
E) These APs depend on voltage-gated calcium channels.
F) These APs never truly return to Vrest - ✅🌹CORRECT ANSWER-A) These APs are triggered by APs
transferred by pacemaker or conduction system cells within the heart
C) These APs depend on voltage-gated sodium channels
E) These APs depend on voltage-gated calcium channels
(one best answer) During the heartbeat, contractile atrial cells receive pacemaker action potential
excitation via:
A) Autonomic neurons
B) Conductile cardiac cells
Choice Questions And Bond Italic Answers And
Italic Explanations 2026/2027 (100% Verified
Answers) Update
(one best answer) When Dr. Merriman talks about Ca++ "providing permission to slide", she means that:
A) Ca++ influx from the ISF depolarizes the skeletal muscle cell, initiating contraction
B) Ca++ binding changes the shape of the myosin "hands" so they can grab the actin
C) Ca++ binding changes the shape of a protein that is blocking myosin's access to actin - ✅🌹CORRECT
ANSWER-C) Ca++ binding changes the shape of a protein that is blocking myosin's access to actin
one best answer) When skeletal muscle cells shorten, what actually gets shorter?
A) Actin filaments
B) Myosin filaments
C) Sarcomeres
D) Sarcoplasmic reticulum - ✅🌹 CORRECT ANSWER-C) Sarcomeres
(all that apply) What role(s) does ATP play in skeletal muscle contraction?
A) It powers AT Pase pumps that push Ca++ back into the sarcoplasmic reticulum
B) It powers AT Pase pumps that push Ca++ back into the interstitial fluid
C) It powers the pulling action of the myosin "hands" that in turn slides the actin filament
D) It enables the myosin "hands" to let go of actin and reposition themselves for another slide -
✅🌹CORRECT ANSWER-A) It powers ATPase pumps that push Ca++ back into the sarcoplasmic reticulum
C) It powers the pulling action of the myosin "hands" that, in turn, slides the actin filament
,(one best answer) Which of the following is the best summary of the skeletal muscle stretch reflex?
A) It ensures that skeletal muscle cells relax and lengthen enough that sarcomere sliding filaments can
no longer touch each other, saving the relaxing cell some ATP
B) It helps keep sarcomere sliding filaments overlapping just enough to be able to shorten when
commanded to do so by Ca++
C) It rapidly shortens sarcomere sliding filaments to the point that they completely overlap and have
generated maximal tension/force - ✅🌹CORRECT ANSWER-B) It helps keep sarcomere sliding filaments
overlapping just enough to be able to shorten when commanded to do so by Ca++
What is the cytoplasmic molecule that skeletal muscle (and, as it turns out, cardiac muscle) has that
helps it have as good an oxygen supply as possible, even during extreme physical exertion?
________________________________ - ✅🌹CORRECT ANSWER-myoglobin
What is the cytoplasmic molecule that skeletal muscle (and, as it turns out,cardiac muscle) has that
helps it have as good a glucose supply as possible, even duringextreme physical exertion?
_____________________________ - ✅🌹CORRECT ANSWER-glycogen
Which of the following ATP-regenerating reactions within the muscle do NOT require O2 to occur?
A) Cori Cycle
B) Creatine phosphate dephosphorylation (loss of its phosphate)
C) Electron Transport Chain
D) Glycolysis
E) Krebs Cycle - ✅🌹CORRECT ANSWER-B) Creatine phosphate dephosphorylation (loss of its phosphate)
D) Glycolysis
all that apply) Which of the following are molecules found in abundance within skeletal
musclecytoplasm as adaptations to power contraction even in times of low plasma pO2?
A) Cori Cycle
B) Creatine
C) Creatinine
D) Glycogen
,E) Myoglobin
F) Triglycerides - ✅🌹CORRECT ANSWER-D) Glycogen
E) Myoglobin
When skeletal muscle ismaximally active, the organ called the ________________ accepts lactate waste
dumped intothe blood by the skeletal muscle, converts it back to _____________________, and sends
itback to the skeletal muscle by way of the _______________________. This process is calledthe
__________ __________. - ✅🌹CORRECT ANSWER-Liver
Glucose
Bloodstream
Cori Cycle
Creatine is a nitrogenous molecule made in the ___________________ and transported to the skeletal
muscle via the__________________. When taken up by skeletal muscle cells, MOST creatine is
converted to _______________________ that then serves as a quick way to regenerate ATP by donating
its phosphate group to creatine. A TINY proportion of skeletal muscle creatine is converted to the waste
form known as ____________________ and lost in the urine - ✅🌹CORRECT ANSWER-liver
bloodstream
phosphocreatine (or creatine phosphate)
creatinine
WhatTWO (2) types of fuel molecules does skeletal muscle store for its own use? - ✅🌹CORRECT
ANSWER-Glycogen, Triglycerides
(one best answer) As skeletal muscle's "oxygen debt" is repaid by re-establishing the normalplasma pO2
and reloading O2-binding proteins with O2, which ONE of the following ATP-regenerating pathways is
"reactivated" FIRST?
A) Anaerobic fermentation in the cytoplasm
B) Creatine phosphate in the cytoplasm
C) Glycolysis in the cytoplasm
D) Krebs Cycle in the mitochondria
, E) Electron transport chain in the mitochondria - ✅🌹CORRECT ANSWER-B) Creatine phosphate in the
cytoplasm
(all that apply) Which are features of the action potential depolarization observed in pacemaker cardiac
muscle cells?
A) These APs are triggered by APs transferred by pacemaker or conduction system cellswithin the heart
B) These APs arise spontaneously.
C) These APs depend on voltage-gated sodium channels.
D) These APs depend on voltage-gated potassium channels.
E) These APs depend on voltage-gated calcium channels.
F) These APs never truly return to Vrest - ✅🌹CORRECT ANSWER-B) These APs arise spontaneously
E) These APs depend on voltage-gated calcium channels
A) These APs are triggered by APs transferred by pacemaker or conduction system cells within the heart
all that apply) Which are features of the action potential depolarization observed in contractilecardiac
muscle cells?
A) These APs are triggered by APs transferred by pacemaker or conduction system cellswithin the heart.
B) These APs arise spontaneously.
C) These APs depend on voltage-gated sodium channels.
D) These APs depend on voltage-gated potassium channels.
E) These APs depend on voltage-gated calcium channels.
F) These APs never truly return to Vrest - ✅🌹CORRECT ANSWER-A) These APs are triggered by APs
transferred by pacemaker or conduction system cells within the heart
C) These APs depend on voltage-gated sodium channels
E) These APs depend on voltage-gated calcium channels
(one best answer) During the heartbeat, contractile atrial cells receive pacemaker action potential
excitation via:
A) Autonomic neurons
B) Conductile cardiac cells
