Circulation Practice Questions

Prothrombin is an α₂-globulin synthesized by the liver. Without adequate vitamin K or healthy hepatocytes, prothrombin levels fall and clotting is impaired. The kidney does not make prothrombin.

The right coronary artery typically gives off the right (acute) marginal artery along the right ventricular border and the posterior interventricular (posterior descending) artery. The LAD and circumflex are branches of the left coronary system.

Most cardiac veins drain into the coronary sinus, which then empties into the right atrium.

The tricuspid valve is best auscultated at the left lower sternal border, around the 4th–5th intercostal spaces near the xiphoid.

During ventricular systole, the ventricles contract and eject blood, raising aortic pressure.

Ventricular volume falls, S1 (“lub”) marks the start of systole, and the P wave (atrial depolarization) occurs before ventricular systole.

During ventricular diastole, the ventricles relax and fill, so ventricular volume increases.

S2 (“dub”) marks the onset of diastole. The T wave (ventricular repolarization) occurs at the end of systole, just before diastole begins. Aortic pressure generally falls in diastole.

The innermost vessel layer (tunica intima) is lined by endothelium, a single layer of simple squamous epithelium that provides a smooth, antithrombotic surface and regulates vascular tone.

Angiotensin II directly stimulates the zona glomerulosa of the adrenal cortex to secrete aldosterone, which increases Na⁺ reabsorption (and thus water) to raise blood pressure. Renin is upstream (kidney), and calcitonin/thyroxine are thyroid hormones.

Ejection fraction (EF) is a percentage of the end-diastolic volume ejected. Blood pressures don’t directly compute CO.

Left ventricular failure elevates pulmonary venous and capillary hydrostatic pressures, pushing fluid into alveoli—pulmonary edema. Right-sided failure more often causes systemic venous congestion.

The aortic arch gives off:

1. Brachiocephalic trunk
2. Left common carotid
3. Left subclavian

The brachiocephalic then splits on the right into the right common carotid and right subclavian.

The brachiocephalic trunk divides into the right common carotid and the right subclavian arteries. On the left, these vessels arise separately from the arch.

The celiac artery trifurcates into the left gastric, splenic, and common hepatic arteries to supply foregut organs.

Branches of the descending thoracic aorta include bronchial, esophageal, mediastinal, pericardial, posterior intercostal, and superior phrenic arteries. Renal arteries arise from the abdominal aorta.

Major abdominal aorta branches include inferior phrenic, celiac trunk, SMA, renal, gonadal, lumbar, IMA, median sacral, and it terminates in the common iliac arteries. Mediastinal branches belong to the thoracic aorta.

The femoral artery gives off superficial circumflex iliac, superficial external pudendal, deep external pudendal, profunda femoris, and others. The deep circumflex iliac usually arises from the external iliac (not femoral).

Portal vein tributaries include the splenic, superior mesenteric, inferior mesenteric, and gastric veins. The subclavian vein is systemic and not part of portal drainage.

Inside the cranium, the right and left vertebral arteries unite to form the basilar artery, which later contributes to the posterior cerebral arteries via the circle of Willis.

A typical value is about 40 mmHg. It is not the sum, inverse, or half of systolic.

The impulse spreads from the SA node to the AV node through specialized atrial internodal pathways.

Purkinje fibers and bundle branches conduct impulses in the ventricles. The vagus nerve modulates rate/AV conduction but isn’t the physical pathway between nodes.