Exercise Physiology Questions and Answers

Answer: C

The assertion is true and the reason is false, option C. Internal (tissue) respiration is the exchange of gases between the blood and the cells through the tissue fluid. The reason is false because pulmonary circulation, between the heart and lungs, is not the same as systemic circulation, which carries blood from the heart to the rest of the body.

Options A and B accept the reason as true, and D rejects the assertion.

Answer: B

In descending order the body parts are system, organ, tissue and cell, which is IV, III, II, I, option B. Cells form tissues, tissues form organs, and organs working together form a system.

Options A and D are ascending or mixed orders, and option C starts with the organ, ahead of the system, and then goes to the cell before the tissue.

A familiar example runs from a muscle cell to muscle tissue, to the biceps as an organ, to the muscular system, and the question asks for that sequence taken from the largest unit down to the smallest.

Answer: C

The aorta is the first artery to leave the heart, the pulmonary vein brings oxygenated blood to the heart from the lungs, the vena cava brings deoxygenated blood to the heart and the coronary arteries supply oxygenated blood to the heart muscle: a-iv, b-i, c-v, d-ii, option C.

Item iii, bringing deoxygenated blood to the lungs, is the pulmonary artery and is not paired with any item in the list. Options A, B and D give the aorta or the vena cava a function that belongs to a different vessel.

Answer: C

During strenuous exercise the main reason for the onset of fatigue is the formation of lactic acid. As the muscles work harder than the oxygen supply can meet, glycogen is broken down without oxygen, lactic acid builds up, and the rise in acidity interferes with muscle contraction.

An oxygen debt is the extra oxygen taken in after exercise, so it is a result and not the cause of fatigue. Complete depletion of oxygen does not happen in the muscles in this way, and a rise in carbon dioxide stimulates breathing but is not the chief cause of fatigue.

Answer: A

Metabolic adaptation is the adjustment of the metabolic rate to the increased demands of the work load. When training raises the load, the body changes its energy production, and the enzymes and fuel use change so that the demand is met.

'Metabolic rate suspension' means stopping metabolism, which would end life. 'Metabolic impulsion' and 'adaptation of metabolic ratio' are not terms with this meaning. In an athlete this shows as a higher use of fat, a bigger store of glycogen and more efficient enzymes after months of training.

Answer: C

Both statements are right. Muscular power is the rate of doing work and so reflects the speed of contraction. It depends on the proportion of fast-twitch to slow-twitch fibres, since fast fibres contract more quickly and give more power.

The choices that reject either statement are wrong. Power equals force times velocity, so a muscle that contracts both strongly and fast has the greatest power, as in jumping and throwing.

Answer: D

Energy sources for muscular exercise become available in the order ATP (III), phosphocreatine (IV), glycogen (II) and triglyceride (I). ATP stored in the muscle is used at once, phosphocreatine rebuilds it within seconds, glycogen follows through glycolysis, and fat supplies energy for long, slow work.

The other sequences put glycogen or fat before the immediate stores, which reverses the speed at which they can be used. In a 100 m sprint ATP and phosphocreatine supply nearly all the energy, and in a marathon fat is the main fuel, which shows the sequence.

Answer: B

The correct matching is I-1, II-3, III-4, IV-2. The thyroid is a gland, cytoplasm is a part of the cell, the ball and socket joint is found at the shoulder, and the medulla is a part of the brain.

This is code (B). The other codes pair the thyroid with the brain, cytoplasm with a gland or the ball and socket joint with the cell, none of which is true. The medulla oblongata lies at the base of the brain, joining it to the spinal cord, and it controls breathing and the heartbeat.

Answer: C

The pancreas performs both endocrine and exocrine functions. Its exocrine part secretes digestive enzymes into the small intestine through the pancreatic duct, while its islets of Langerhans secrete insulin and glucagon directly into the blood, which is the endocrine function.

The liver is a gland that secretes bile through a duct and does many metabolic jobs, but it is not classed as an endocrine gland. The kidneys filter blood and form urine, and they release some hormones such as erythropoietin, but they have no exocrine secretion through ducts in the digestive sense. The gall bladder only stores and concentrates bile and has no endocrine role.

Answer: B

The systemic circulation carries oxygenated blood from the left side of the heart to all parts of the body and brings deoxygenated blood back to the right side. Its purpose is therefore to supply \(O_{2}\) and nutrients to the tissues (I) and to bring \(CO_{2}\) and other wastes away from them (III), so I and III are correct.

Purification of blood (II) is mainly the work of the lungs, which take up oxygen and release carbon dioxide in the pulmonary circulation, and of the kidneys and liver. Removal of urine from blood (IV) is a filtration function of the kidneys, not the purpose of the circulation itself. Hence I and II, II and IV, and III and IV are wrong.