Cardiovascular System

Antidiuretic hormone decreases the volume of urine formed by causing water to be reclaimed from the DCT and collecting duct. Hence blood osmolarity will not increase and BP will not decrease.

Red blood cells are mixed with a solution that is isotonic: that is, will not cause any net movement of water into or out of the cell. Choice D is wrong as using plasma would defeat the purpose of donating in the first place.

Convert cm to m and kPa to Pa. The pressure at the cannula must be greater than 5 kPa (5000 Pa). Use the value in choice A: P = 10 × 1000 kg/m³ × 0.25 m = 2500 Pa = 2.5 kPa. The answer is only half of the pressure required (5 kPa); hence a head of at least twice 25 cm is required. Choice D is the only one that will do.

Systemic veins contain about 64% of the blood volume, while systemic arteries contain about 13%.

Blood passes through the pulmonary valve as it leaves the right ventricle. Choices A and D are the same valve.

Angiotensin-converting enzyme is known as “ACE”. An ACE inhibitor will prevent this enzyme from converting angiotensin I into angiotensin II. Hence the blood pressure raising effects of angiotensin II will be prevented.

The partial pressure of oxygen is proportional to its percent concentration in the mixture of gases. 20% of 100 kPa = 20 kPa.

Intercalated discs attach a cardiac muscle cell to its neighbour. This connection allows rapid passage of the depolarisation signal from cell to cell so that ventricular contraction is coordinated. Hence the ventricles behave as a “functional syncytium”.

Pulmonary refers to the lungs.

The number of millilitres of blood per minute is volume flow rate and cardiac output. They are the same thing.