Physiology and Sports Questions and Answers CBSE Class 12 Board Exams

1 Mark Questions

Answer : Physiology is the study of how the human body functions i.e. how the organs, systems, tissues, cells and molecules work together to maintain our internal environment.

Answer : Blood pumped by the heart in one minute is :

= Cardiac output

= heart rate x stroke volume

= 72 beats/min x 70mL approximately

= 5040 mL/min

Answer : The amount of blood pumped into the aorta with every heartbeat is known as the stroke volume. In an untrained male, it is 70-9- mL/beat.

Answer : Oxygen uptake or VO2 is the oxygen consumption or uptake per kilogram of body weight. It is a good measure of the respiratory system.

Answer : The amount of blood pumped into the aorta with every heartbeat is known as the stroke volume. In an untrained male, it is 70-90 mL/beat.

Answer : Tidal volume is the amount of air inspired or expired per breath. This can be increased with the help of endurance training. In untrained individuals, tidal volume is about 500mL/breath, whereas in trained persons, it is increased to 600-700 mL/breath.

Answer : The muscular system of males are stronger than females as they have more muscle mass and muscle composition. The bones and ligaments attached to the muscles are stronger in males than in females.

Answer : Hypertrophy of muscles or muscular hypertrophy is an increase in muscle mass and cross-sectional area. The increase in dimension is due to an increase in the size (not length) of an individual muscle fibres.

Answer : Regular exercise delays the onset of fatigue as exercise develops the fitness levels and increases endurance thereby delaying fatigue.

Answer : One physiological change which occurs due to ageing is reduction in muscle size and strength.

Answer : With advancing age, there is an increase trend to accumulate fat because the ability to release stored fatty acids from adipose tissues for energy decreases.

Answer  : Physiology is the study of how our organs, systems, tissues, cells etc function. This is essential to understand how to attain physical fitness in order to enhance the performance in sports.

3 Marks Questions

Answer : Regular exercise keeps the human body livelier, fitter and in better condition, thus delaying the ageing processes, as given below:

• Exercise reduces the loss of elasticity from the lungs and chest wall.
• Exercise increases muscle strength and hypertrophy by increasing the cross-sectional area of the Slow Twitch Fibres (STF) and Fast Twitch Fibres (FTF). This slows down ageing.
• The body composition changes due to exercise by reducing the fat content of the body, thus slowing down the ageing process.
• Exercise  improves flexibility by strengthening the musculoskeletal systems, thereby preventing the stiffening of joints. It improves the elasticity of tendons, ligaments and joint capsules.

Answer : As in individual gets older, there is a decline in muscle size. It is believed that this decline is due, in part, to a reduced amount of protein as well as a decline in the number and size of muscle fibres.

This may be due to dengenerative diseases generally associated with advancing age affecting the nerve fibres. Increases in strength are related to muscle fibre hypertrophy, meaning that strength increases parallel to increases in muscle size. As people get old and the muscle size decreases, there is a parallel decrease in muscular strength.

5 Marks Questions

Answer : Physiological factors determining components of physical fitness are:

i) Muscular Strength : This is the maximum force or tension of a muscle or a muscle group can exert against a resistance. Physiologically the muscle will increase in strength only if it has to increase its workload beyond what is ordinarily required of it.

ii) Power : This is the ability of the body to release maximum muscle contraction in the shortest possible time.

iii) Speed : This is the rapidity with which one can repeat successive movements of the same pattern.

iv) Muscular Endurance : This is the ability of a muscle or muscle group to perform repeated contractions against a resistance / load or to sustain contraction for an extended period of time with less discomfort and more rapid recovery.

v) Agility : This is the ability of a person to change direction or body position as quickly as possible and regain body control to proceed with another movement.

vi) Flexibility : This is a quality of the muscles, ligaments and tendons that enables the joints of the body to move easily through a complete range of movements.

Answer : Physiological differences between males and females are:

Basis	Males	Females
Strength	Men are stronger than women because they have greater muscle mass.	Women are not as strong as men because their muscle mass is less. On an average, women possess 2/3rd the strength possessed by men.
Cardiovascular functions	In intense exercises, men have better cardiac output than women.	Women have lower cardiac output than men.
Respiratory Functions	The respiratory functions are better in men. They have more haemoglobin content and VO2.	The respiratory functions in women lack in certain parameters related to haemoglobin content and VO2.
Endurance	The endurance level in men is high by around 10% because of high haemoglobin content and better blood circulation.	The endurance level in women is even higher due to greater number of white fibre in the muscle.
Bones and ligaments	Men have longer and stronger bones and ligaments but due to a narrow pelvis and higher centre of gravity, they have poor balance.	Women’s bones and ligaments are not strong, but they have a wider pelvis and lower centre of gravity that provides a better balance.

Answer : The effects of exercise on the cardiovascular system are:

i) Cardiac Output : It is the amount of blood pumped by the heart in one minute. Cardiac output increases with the intensity of the exercises. At rest it is 4 to 6 L/min and during exercises it is 20 to 40 L/min.

ii) Heart Rate : The number of cardiac contractions in one minute is called heart rate. During exercises the heart rate goes up.

iii) Stroke Volume : The amount of blood pumped into the aorta with every heartbeat is known as the stroke volume. The stroke volume increases in response to the intensity of the exercises.

iv) Blood Flow : With increasing intensities of exercise, a greater accumulation of lactic acid and the production of other metabolic end products occurs. This increases blood flow in the cardiac output, while decreases in kidneys and abdomen.

Answer : The adaptive effects that take place in body after engaging in exercise for a longer period are:

i) Increase in Heart Size : We cannot do the exercise on our heart directly, but when we perform any exercise regularly, our heart size increases. Exercising develops the muscles of the heart.

ii) Increase in Heart Rate : Generally an adult has a heart rate of 72 beats per minute while resting, but when he exercises, his heart rate increases as per the intensity and duration of the exercise.

iii) Increase in Stroke Volume : Stroke volume is the quantity of blood which the heart pumps out in a single stroke. Due to the heart’s size increasing, the stroke volume increases.

iv) Decrease in Cholesterol Level : Regular exercise reduces the cholesterol level in our blood, which has a direct link with the blood pressure.

v) Increase in Number and Efficiency of Capillaries : Regular exercise increases the number of capillaries and their efficiency.

vi) Reduced Risk of Heart Diseases : Regular exercise gradually reduces stress related hormones from circulating in the blood. This results in increase of blood flow in the blood vessels, which in turn, lowers the risk of building up of plaque which affects the heart. Hence, regular exercise reduces the risk of heart diseases.

Answer : The respiration system consists of organs responsible for taking in oxygen for respiration and releasing carbon dioxide and water vapour, which are the waste products formed during respiration. The passage in the nose, windpipe (trachea), bronchi, lungs and air sacs are the main organs of the respiratory system.

A trainer can improve the respiratory system with the help of exercise by :

i) Increasing the Lung Volume and Capacity : Vital capacity, which is the maximal volume of air forcefully expired after a maximal inspiration, in a normal untrained person may be 3-4 litres, but in a trained athlete this goes upto 5-6 litres.

ii) Reducing the Breathing Frequency : In a normal untrained individual, the resting breathing frequency is about 12-20 breaths/min, whereas in trained athletes, it comes down to 7-8 breaths/min.

iii) Maximising the Minute Ventilation : Maximum minute ventilation in an untrained individual is about 100 L/min, whereas in trained athletes it increases to more than 150-160 L/min.

iv) Increasing Tidal Volume : In an untrained individual, tidal volume is about 500 mL/breath, whereas in trained persons, it increases to more than 600-700 mL/breath.

v) Increasing the Ventilatory Efficiency : Normally, 15 L of air is required to get 1 L of oxygen but a trained individual gets the same amount of oxygen , i.e. one litre, from less air i.e. 12 L.

vi) Increasing the Pulmonary Diffusion : During maximal level of exercise, more alveoli become active for diffusion. The size of the alveoli is also increase, which provides more space for diffusion of gases such as oxygen (O2) and carbon dioxide (CO2).

Answer : i) Respiratory Changes : Endurance training in the elderly reduces the loss of elasticity from the lungs and chest wall. This is evident in the endurance trained older athletes, who have very slightly reduced pulmonary ventilatory capacity.

ii) Muscular Strength : Studies report an increase in the strength of males and females following strength training. Physical activity in the form of stimulus to the muscle plays a significant role in the fibre type distribution with advancing age. Moderate levels of physical activity tends to improve muscle strength even in the older women.

iii) Body Composition Changes : The body fat content of sedentary subjects (men and women) is significantly higher than their physically active counterparts. This is because the older athletes expend a high number of calories and moreover, their dietary habits are strictly monitored as compared to their sedentary counterparts.

iv) Felxibility : Flexibility is dependent upon the arrangement of attachment of the ligaments to the bones as well as elasticity and length of the tendons that envelop the joints. Low or medium intensity exercise e.g. walking, is reported to significantly improve flexibility. Exercise strengthens the musculoskeletal systems, thereby preventing the joints from stiffening in one position.

Thus a regular and appropriately designed exercise and training programme can maintain functional fitness in most elderly persons.

Value Based Questions

Answer : i) The physiological benefits are:

a) It improves the cardiovascular system.

b) It improves the circulatory system.

ii) If old people do not maintain their physical fitness then they can become obese, unhealthy as the internal systems will not work properly. There will be more stress, greater chances of injury and less flexibility.

Answer : i) The values shown by Mr am are good moral character, self-discipline, decisiveness, logical and decision maker.

ii) Old people complain of joint pains because flexibility and elasticity of the ligaments and length of the tendons enveloping joints decreases with age.

iii) Exercises strengthen the musculoskeletal systems, thereby preventing the joints from stiffening in one position. This relieves pain.

Answer : The saying is correct because, by giving up your usual activities, you speed up the ageing process. In fact, the ageing process can be slowed down by continuing your usual activities.

Regular exercise keeps the human body livelier, fitter and in better condition, thus delaying the ageing processes like loss of elasticity from the lungs and chest wall, reduction in muscle strength and hypertrophy, increase in fat content of the body, reducing flexibility by weakening of the musculoskeletal system, thereby causing the stiffening of joints and so on. So, we should not reduce our normal activities, if we want to slow down our ageing.