Zoology MCQs for NEET — Practice Questions with Answers

Thrombin is the enzyme that converts fibrinogen into fibrin during the blood clotting process. Fibrin forms a mesh that traps blood cells to form a clot, which is essential for stopping bleeding and initiating wound healing.

The tricuspid valve is located between the right atrium (auricle) and the right ventricle. It prevents the backflow of blood from the right ventricle to the right atrium during ventricular contraction.

The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart. This is one of the few veins in the body that carries oxygen-rich blood.

The T wave in an ECG (electrocardiogram) represents ventricular repolarization, which corresponds to the ventricles' diastole or relaxation phase.

Carbon monoxide (CO) binds to haemoglobin more effectively than oxygen, forming carboxyhaemoglobin. This decreases the blood's oxygen-carrying capacity, leading to reduced oxygen delivery to tissues and organs.

The normal range for the number of leucocytes (white blood cells) in a cubic millimeter of blood is typically between 5000-8000. Leucocytes are a crucial component of the immune system.

The sinoatrial (SA) node, also known as the pacemaker of the heart, is located in the right upper corner of the right atrium. It is responsible for initiating the electrical impulses that set the rhythm for the heart to beat.

Erythroblastosis fetalis is a condition that leads to the destruction of the baby's red blood cells (RBCs). This typically occurs when there is an incompatibility between the blood types of the mother and the baby, most commonly involving the Rh factor.

A person with both antigen A and antigen B on the surface of their red blood cells has blood type AB. Such a person does not possess antibodies against A or B antigens in their serum, can donate blood only to AB blood group individuals, and is considered a universal recipient because they can receive blood from any ABO blood group.