Physiology I- Exam 3 Tangs Practice Questions Flashcards
- Which of the following statements regarding carbon dioxide (CO2) transportation in the blood
is correct?
a. Carbon dioxide is transported mainly by hemoglobin.
b. Carbon dioxide is transported mainly as bicarbonate (HCO3-) or carbamino compounds.
c. Carbon dioxide is transported primarily in a dissolved form.
d. Carbon dioxide is transported in red blood cells.
b. Carbon dioxide is transported mainly as bicarbonate (HCO3-) or carbamino compounds.
- A specialized conduction system propagates the electrical activities in the heart. Which of the
following statements best describes this specialized conduction system?
a. Each normal heartbeat is initiated by an action potential that arises spontaneously in one of the pacemaker cells in the atrioventricular node pacemaker cells.
b. The atrioventricular node and the first part of the atrioventricular bundle (Bundle of His) are the only routes for propagating action potentials from the atria to the ventricles.
c. The AV Bundle beyond the first part, the left and right bundle branches, and the Purkinje fibers have the unique property of prolonged conduction of action potentials (50 to 150
milliseconds).
d. Atrial contraction is followed immediately by ventricular contraction.
b. The atrioventricular node and the first part of the atrioventricular bundle (Bundle of His) are the only routes for propagating action potentials from the atria to the ventricles
Electrocardiogram (ECG) waves reveal electrical events in the heart. A typical lead I ECG
has P, QRS, and T waves. The Q wave corresponds to the following electrical event in the
heart:
a. Atrial depolarization.
b. Inter-ventricular septum depolarization.
c. Atrial repolarization.
d. Ventricular repolarization.
b. Inter-ventricular septum depolarization.
- Blood volumes in the atria, ventricles, and arteries change during a cardiac cycle. Which of
the following statements correctly describes the blood volume change?
a. Stroke volume is the total volume of blood pumped by one ventricle in 1 minute
b. End-diastolic volume is the blood volume in each ventricle at the end of the systole
c. Cardiac output is the volume of blood ejected from one ventricle in one beat
d. End-systolic volume is the blood volume in each ventricle at the end of the systole
d. End-systolic volume is the blood volume in each ventricle at the end of the systole
- Mean aortic pressure is critical for blood supply and determined by cardiac output and total
peripheral resistance (TPR). Which of the following statements correctly describes the
regulation of mean aortic pressure?
a. The total peripheral resistance (TPR) is below the normal in a patient with hypertension
b. The total peripheral resistance (TPR) is above the normal during exercise
c. The mean aortic pressure is negligibly changed during exercise
d. The cardiac output is above normal in a patient with hypertension
c. The mean aortic pressure is negligibly changed during exercise
- Which of the following statements correctly describes one mechanism by which arteriolar
vasodilation speeds the delivery of oxygen and metabolic substrates to the exercising muscle
cells?
a. Decrease in the diffusion area
b. Increase in the distance between each exercising skeletal muscle cell and the nearest open
capillaries
c. Increase in the driving force for the diffusion of oxygen and metabolic substrates
d. Decrease in diffusion co-efficiency
c. Increase in the driving force for the diffusion of oxygen and metabolic substrates
- Metabolic control is a local mechanism that matches tissue blood flow to its metabolic rate.
Such a local mechanism is essential for controlling blood flow in critical organs such as the
brain, the heart (i.e., coronary circulation), and working skeletal muscles. Which of the following
biological processes is increased when the metabolic rate in tissue is increased?
a. Pre-capillary sphincter tone
b. Number of open capillaries
c. Diffusion distance
d. Arteriolar resistance
b. Number of open capillaries
