Cardiovascular System

Pressure in the LV will rise as the myocardium contracts until pressure in the LV is greater than the pressure in the aorta. When this happens, the aortic valve will be forced open, and blood will move from the LV into the aorta through the aortic valve.

Angiotensin II promotes vasoconstriction which increases peripheral resistance which increases BP. It also stimulates the adrenal glands to produce aldosterone. It is aldosterone that causes an increase in Na⁺ absorption; hence choice B is a better answer than D.

Pascal’s states that pressure applied to an enclosed fluid is transmitted undiminished throughout the fluid. The LV pushes blood into the aorta at pressure. This pressure distends the artery walls of the brachial artery – even though it is 70 cm away from the heart – and we can feel the pulsations as pressure rises and falls.

When the myocardium is relaxed (in diastole), and the aortic valve is shut, blood from the aorta flows into the coronary arteries.

An aneurysm describes a blood vessel distended beyond normal and in danger of rupturing.

Fenestrated capillaries have pores (windows/fenestrae) which penetrate the endothelial lining which facilitates the passage of material through them.

Poiseuille’s law states that volume flow rate is proportional to radius to the fourth power, so blood flow rate would be 1/3 ×1/3 ×1/3 ×1/3 = 1/81.

Neutrophils are microphages – phagocytes of bacteria. Thrombocytes and erythrocytes are not WBC.

Blood passes from the right atrium into the right ventricle, by going through the tricuspid valve.

The larger is the vessel diameter, the less will be the resistance to blood flow. The other choices are nonsense.