FREE NEET Biology Practice MCQ Test: Body Fluids And Circulation Exercise 1 Questions Answers With Detailed Explanations [PDF]

Answer: (a)

Answer: (a)

A special neural centre in medulla oblongata can moderate the cardiac function through autonomic nervous system (ANS). Neural signals through the sympathetic nerves (part of ANS) can increase the rate of heart beat, the strength of ventricular contraction and thereby the cardiac output. Parasympathetic neural signals (component of ANS) decrease the rate of heart beat, speed of conduction of action potential and thereby the cardiac output.

Answer: (a)

Answer: (a)

Answer: (b)

Answer: (c)

Systemic circulation involves circulation of blood between heart and various body parts except lungs. The oxygenated blood from the left ventricle of the heart is passed through aorta, arteries, arterioles and capillaries and reaches the tissues. The deoxygenated blood collected from the tissues by venules, veins and vena cava is carried to the right atrium. The systemic circulation provides nutrients, O2 and other essential substances to the tissues and takes CO2 and other harmful substances away for elimination.

Answer: (d)

Answer: (a)

Answer: (b)

Answer: (b)

Basophils secrete histamine, serotonin, heparin, etc., and are involved in inflammatory reactions.

Answer: (d)

Cardiac output = Stroke volume × heart beats per minute

∴ Stroke volume = ${\text"Cardiac output"}/{\text"Heart beats per minute"}$

= ${5250}/{75}$ = 70 ml

Answer: (b)

Answer: (d)

Neutrophils, are the most abundant type of white blood cells and form an integral part of the immune system. These phagocytes are normally found in the bloodstream. However, during the acute phase of inflammation, particularly as a result of bacterial infection, neutrophils leave the vasculature and migrate toward the site of inflammation in a process called chemotaxis. They are the predominant cells in pus, accounting for its whitish/yellowish appearance. Neutrophils react within an hour of tissue injury and are the hallmark of acute inflammation. Monocytes are also phagocytes but take 7-8 hours to reach at the site of injury. Acidophils and basophils are not phagocytic in nature.

Answer: (c)

Answer: (d)

Answer: (a)

Answer: (c)

Answer: (b)

The left ventricle pumps blood into the aorta.

Answer: (a)

The principal function of B-lymphocytes is to make antibodies against soluble antigens that are important in regulating humoral immunity. On the other hand, RBCs transport oxygen, T-lymphocytes play a central role in cell mediated immunity and neutrophils act as phagocytes.

Answer: (d)