Human Physiology Quiz Answers: Blood, Heart, and Circulation

Physiology Assessment Solutions

Blood Composition and Function

• 1. e. A and C: Lungs and Intestines bring in oxygen and nutrients into the blood.
• 2. d. 92%
• 3. a. Fibrinogen
• 4. c. The heme group
• 5. a. One
• 6. d. Leukocytes: Leukocytes (white blood cells) are not dissolved in plasma; they are cells that circulate or reside in tissues.
• 7. d. Erythropoietin: The hormone that stimulates red blood cell production is erythropoietin.
• 8. a. 250,000,000: Each red blood cell contains approximately 250 million hemoglobin molecules.

Hemostasis and Clotting

• 9. b. Fibrinogen: Thrombin converts fibrinogen into fibrin to form blood clots.
• 10. c. Tissue factor: Tissue factor, exposed upon damage, activates plasma proteins in the clotting cascade.
• 11. d. Plasmin: Plasmin dissolves blood clots by breaking down fibrin.

Cardiovascular Dynamics and Poiseuille's Law

• 12. c. Ventricles from the arteries: Semilunar valves separate the ventricles from the arteries.
• 13. d. Nothing
• 14. d. Reducing the radius by half: Flow is most sensitive to radius; halving the radius reduces flow dramatically due to Poiseuille’s law.

Cardiac Cycle and Muscle Physiology

• 15. b. The atrioventricular valves close: This prevents backflow into the atria when the ventricles contract.
• 16. True: Cardiac contractile cells have sarcomeres just like skeletal muscle.
• 17. b. Left ventricle: The left ventricle pumps oxygenated blood into the aorta.
• 18. c. 200 ms: The plateau phase in cardiac muscle lasts about 200 milliseconds.
• 19. c. Calcium: Calcium influx maintains the plateau phase of the action potential.
• 20. d. Skeletal DHP receptors do not act as channels, and cardiac ones do: Cardiac DHP receptors are actual calcium channels; skeletal ones act more like voltage sensors.

Electrocardiogram (ECG) Interpretation

• 21. b. PR segment (between P wave and QRS complex): This is when the atria contract and push blood into the ventricles.
• 22. Between the R and T waves
• 23. Isovolumic ventricular contraction
• 24. The two valves are never open at the same time
• 25. Atrial and ventricular diastole
• 26. The R wave

Cardiac Electrophysiology and Regulation

• 27. Sodium
• 28. Beta-1 adrenergic receptors

Blood Vessels and Fluid Balance

• 29. Capillaries
• 30. A and C (Arteries and Veins)
• 31. A and B (Water and Ions)
• 32. Increased sympathetic, decreased parasympathetic
• 33. Into the capillary
• 34. Increasing hydrostatic pressure in capillaries
• 35. 30,000 mL
• 36. ECF is removed by the lymphatic system