Question

A birth defect called transposition of great vessels results in the pulmonary trunk emanating from the left ventricle and the aorta stemming form the right ventricle. As a result, ____ventricle is thicker-walled.

The hydrostatic pressure gradient drives water_________capillaries, and the colloid osmotic pressure drives water_______capillaries.

The AV node delay (or PR segment in ECG) :

		allows the atria and ventricles to depolarize and contract as a unit
		allows the two ventricles to depolarize and contract separately
		allows the atria and ventricles to depolarize and contract separately
		speeds up the impulse transmission from the atria to the ventricles

Fernando has blood type A while Maria has blood type O. Their son, Juan, needs blood transfusion due to a medical condition. Which of the following blood type(s) cannot donate blood to Juan?

Note Juan' paternal grandfather has type O blood.   

		A and O
		B only
		B and AB
		B and O

Answer 1

Answer:

Answer 1. Right ventricle is thicker walled

Explanation: Transposition of the great vessels is a congenital disease that is the condition is present since the birth of a child. In this condition the pulmonary arteries and the aorta are reverse transposed. That is the aorta originates from the right ventricle as against the left ventricle. Similarly, the pulmonary arteries originate from the left ventricle as against the right ventricle. Since aorta is meant to transport the pure oxygenated blood to the different body parts as a result of which the work pressure on the corresponding ventricle is more. Henceforth, the walls of the right ventricle will be thicker than the left ventricle

Answer 2. Hydrostatic pressure gradient drives water “away” from the capillaries into the tissues, and the colloid osmotic pressure drives water “into” the capillaries

Explanation: Hydrostatic pressure is the pressure which is exerted by the fluid component of the blood as against the capillary walls. The force which gets established because of the concentration gradient between the blood and the capillaries is responsible for movement of water from the capillaries to the body tissues

Similarly, the blood has a high concentration of the solutes. And the same is less within the capillaries. Osmotic pressure is the pressure which stops the movement of the water molecules through the membrane. The same plays a very significant role in the active reabsorption of water molecules from the interstitial cells into the capillaries such that it again is returned back to the body. Thus due to the osmotic pressure in place, the water moves into the capillaries

Answer 3. Option B (allows the two ventricles to depolarize and contract separately)

Explanation: AV Node is also called as the pace setter. It is called as an atrio-ventricular node as it is located at the junction of the atria and the ventricles. It is made of the nodal tissues which are self excitatory in nature. They receive the impulses from the SA (sinoatrial node) which leads to the contraction of the atria leading to atrial depolarization.

After they receive the impulses from the SA node, they pass the same information to the ventricles thus leading to their depolarization as a result of which they contract. Thus, there is a time lag between the atria and the ventricles

Answer 4. Options: B only, B and AB, B and O

Explanation: Per the genotypic constituents of the parents; mother with blood group O and father with blood group A. So, genetically, their child Juan has a blood group of A. Blood group A means the surface of the RBCs has an antigen A and antibodies being anti-B. Which means the person’s body can accept the blood only from the people with blood group O as they do not have any antigens; blood group A as they have the same antigen due to which they cannot be considered as an antigen within the person’s body.

However a person with blood group B or AB cannot be considered as blood donors as they have an antigen B on the surface of their RBCs. While blood group B only has B antigen, person with blood group has both A and B antigens on their surfaces. These antigens can be counteracted by the anti-B antibodies present on the surface of RBC. Hence, these persons cannot donate their blood to Juan.