Why should you titrate beta-blockers in patients with coronary artery disease?
Loading a patient with a high dose of beta-blocker can be dangerous since they block receptors in heart muscles. These muscles need time to adjust to the blockade we are introducing. If we don't allow for this settling-in period then we risk hypotension, bradycardia, metabolic acidosis and possibly cardiac arrest.
Why is it easier to float in saltwater than in fresh water?
The answer has to do with increasing density. Adding salt (NaCl) to water will create an aqueous solution where we increase the mass of the solution without drastically changing the volume of the solution. Water has a molar mass of about 18 g/mol. Salt weighs about 58 g/mol. 1 litre of water weighs less than 1 litre of saltwater, therefore saltwater is more dense. An analogy would be that your chair is very dense and so you "float" on your chair. Alternatively, air is light so you "sink" in air.
Suppose someone develops a blot-clot in either of their legs. If that clot were to dislodge itself, where can it ultimately end up?
Without looking at a diagram of the circulatory system, realize that veins carry deoxygenated blood. In order for blood to become reoxygenated it must pass through the lungs to pick up atmospheric oxygen. This implies that if a clot were to form in a deep vein of the leg then it may travel to the pulmonary artery.