Physio midterm

Dr. Omar is a trauma surgeon, he isolated four specimens of human blood(a,b,c, and d). He then added random portions of solutes to each specimen. Upon microscopic analysis, which human blood specimen Dr. Omar separated is in a hypotonic solution?

• a

• b

• c

• d

• none of the specimens are in a hypotonic solution

Which of the following is false regarding a sarcomere?

• It is the area between two z-lines

• It is composed of one A-band between two halves of I-band

• It is a structural and functional unit of cardiac and skeletal muscle contarction

• Calcium binds to troponin C to unmask active site of thin filaments

• Dystrophin is a protein that connects thick filaments to sarcolemmal proteins

Which of the following is true about repolarization of skeletal muscles action potential?

• It is characterised by activation of sodium channels only

• It is charactarised by deactivation of potassium channels only

• It is charactarised by inactivation of sodium channels and activation of potassium channels

• It is charactarised by deactivation of potassium channels and activation of sodium channels

• None of the choices are true

Which of the following is involved in the pathway of calcium in smooth muscle cells?

• Calmodulin

• Troponin

• Tropomyosin

• Actin filaments

• DHP receptor

The following figure shows the isometric legnth-tension relationship in a skeletal muscle. Which of the following statements is incorrect regarding the figure shown?

• E represents the muscle length where active tension is maximal

• B represents the contraction-dependent tension

• C represents the contribution of noncontractile muscle tension to total tension

• C represents passive tension

• A decreases with increased muscle contraction

Shamma is analyzing an ECG result of a patient, and she noticed that QRS waves were 0.5 seconds apart. What is the heart rate per minute (HR) of this patient?

• 200 bpm

• 240 bpm

• 120 bpm

• 160 bpm

• 260 bpm

Which of the following channels are mainly responsible for the plateau stage in ventricular myocyte action potential?

• L-type Ca²⁺ Channels

• T-type Ca²⁺ Channels

• Funny Na⁺ Channels

• Transient K⁺ Channels

• K⁺ Channels

If the end systolic volume (ESV) of a patient is 55 mL, and an end diastolic volume (EDV) of 120 mL. What is the ejection fraction of this patient?

• 54.2 %

• 65.3 %

• 45.8 %

• 69.7 %

• 88.3%

Calcium leaves the sarcoplasmic reticulum through which of the following structures?

• Ryanodine receptor

• DHP receptor

• Calmodulin

• SERCA (sarcoplasmic reticulum Ca²⁺ ATPase)

• Na/Ca exchange pump

Which of the following is the fastest nerve fiber?

• A-β(beta) nerve fibers

• A-α(alpha) nerve fibers

• A-γ(gamma) nerve fibers

• B nerve fibers

• C nerve fibers