Impulses through the conduction system of the heart follow the ordered path:

Correct Answer: C

Rationale: The cardiac conduction system starts at the sinoatrial (SA) node (pacemaker), impulses travel to the atrioventricular (AV) node, then through the atrioventricular bundle (Bundle of His), and finally to the Purkinje fibers, stimulating ventricular contraction.

Correct Answer: B

Rationale: Plasma proteins (e.g., albumin) maintain colloid osmotic pressure (about 25 mmHg), drawing fluid back into capillaries. Lipids and vitamins have minimal osmotic roles, and histamine affects permeability, not pressure.

Correct Answer: C

Rationale: The pulmonary arteries carry deoxygenated blood from the right ventricle (after passing through the right atrium) to the lungs for oxygenation. Pulmonary veins carry oxygenated blood back to the left atrium, the aorta carries oxygenated blood systemically, and the superior vena cava delivers deoxygenated blood to the right atrium.

Correct Answer: A

Rationale: Normal hemoglobin levels are 13.5-17.5 g/dL for men and 12-15.5 g/dL for women. Assuming Bob is male (typical default in such questions), 15 g/dL is within normal limits; if female, it’s still normal.

Correct Answer: A

Rationale: Leukocytes and platelets form ~1% of blood volume; RBCs (formed elements) are ~45%, and plasma is ~55%. The combined fraction is small due to their low numbers relative to RBCs.