Phys Exam 3 Review – Quizzizz

Which of the following skeletal muscle fiber types has the following characteristics – high power production, medium mitochondrial density, and low capillary density?

• Type I

• Type IIa

• Type IIx

• Type IIb

Which of the following is incorrect regarding contractile structures?

• Myosin: thick filament

• Actin: thin filament

• Troponin: thick filament

• Tropomyosin: thin filament

_______ is a protein that acts as a structural support and molecular spring while _______ is a protein that acts as a “molecular ruler” for thin filament assembly.

• a. Nebulin; titin

• b. Titin; nebulin

• c. Titin; troponin

• d. Nebulin; troponin

What initiates the “power stroke” in the steps of muscle contraction?

• Release of inorganic phosphate from myosin

• Release of inorganic phosphate from actin

• Release of ADP from myosin

• Release of ADP from actin

SERCA, PMCA, NCX, and MCU are all examples of proteins that help do what?

• Transport ACh into the motor end plate

• Remove Ca+2 for return to the SR

• Reveal binding sites on myosin

• Create actin filament

Which of the following would NOT cause an increase in blood flow?

• Increased vasodilation

• Increased length of blood vessel

• Decreased vascular resistance

• Decreased viscosity

Which of the following is NOT a trait of cardiac muscle?

• Involuntary control

• Autorhythmic

• Single or double nuclei

• Non-striated

Which of the following is incorrect regarding events on an ECG?

• P wave: atrial depolarization

• PR segment: AV nodal delay

• QRS complex: ventricular depolarization

• T wave: atrial repolarization

In the heart, mechanical events lag behind electrical events.

• True

• False

In stage four of the cardiac cycle, the _______ valves open and blood is ejected from the ventricles and into the periphery.

• Semilunar

• Atrioventricular