FREE NEET Biology Practice MCQ Test: Body Fluids And Circulation Exercise 4 Questions Answers With Detailed Explanations [PDF]

Answer: (d)

Answer: (a)

Presence of calcium will remove heparin - blood anti-coagulant and will promote blood clotting. Sodium oxalate and heparin containing test tubes will not allow the blood to clot.

Answer: (d)

Answer: (c)

Coronary Artery Disease (CAD) or atherosclerosis is a disorder in which the deposition of calcium, fat, cholesterol and fibrous tissue occurs in coronary arteries which makes the lumen of arteries narrower and thereby affect the blood supply.

Answer: (d)

Answer: (d)

When an injury is caused to a blood vessel, bleeding starts which is stopped by blood clotting. At the site of injury blood platelets release platelet factor - 3 and injured tissues release thromboplastin. The two combine to form prothrombinase enzyme which converts prothrombin to thrombin. The latter stimulates formation of fibrin thread or clot. Blood contains an anticoagulant heparin which prevents blood clotting in uninjured vessels.

Answer: (d)

Fibrinogen, the protein of blood plasma is converted to insoluble protein fibrin during the clotting process. The fibrinogen free fluid obtained after removal of the clot, called blood serum is plasma minus fibrinogen.

Answer: (b)

Blood circulation involves the transport of oxygenated blood from the lungs to the left atrium by the pulmonary vein. From the left atrium, the oxygenated blood is pumped into the left ventricle, from where it is taken to all body tissues by aorta.

Answer: (a)

Answer: (c)

Answer: (d)

The most active phagocytic white blood cells are neutrophils and monocytes.

Neutrophil is a type of WBC (leucocyte) that has a lobed nucleus and granular cytoplasm. Neutrophils engulf bacteria and release various substance such as lysozyme and oxidizing agents.

Monocyte is the largest form of WBC in vertebrates. It has a kidney shaped nucleus and is actively phagocytic, ingesting bacteria and cells debris.

Answer: (c)

Answer: (d)

RBCs do not occur in the blood of cockroach. The circulatory system of cockroach is of open type. Viscera lie in the haemocoel immersed in blood called haemolymph. The latter consists of colourless plasma and irregular white corpuscles, the leucocytes. There are no blood vessels except aorta that carries blood from the heart to the haemocoel.

Answer: (d)

Tricuspid valve is the valve in the heart between the right atrium and right ventricle. It consists of three cusps that channel the flow of blood from the atrium to the ventricle. When the right ventricle contracts, forcing blood into the pulmonary artery, the tricuspid valve closes the aperture to the atrium, thereby preventing any backflow of blood. The valve reopens to allow blood to flow from the atrium into the ventricle. Thus, if tricuspid valve is partially non- functional the flow of blood into the pulmonary artery will be reduced.

Answer: (c)

Answer: (a)

Answer: (c)

Answer: (c)

Answer: (c)

Answer: (c)

In the given diagram the P-wave represents the electrical excitation (or depolarisation) of the atria, which leads to the contraction of both the atria. The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole. The T-wave represents the return of the ventricles from excited to normal state (repolarisation). The end of the T-wave marks the end of systole.