CBSE Class 12 Phy. Edu. Unit-8-Physiology & Sports

Unit 8 - Physiology and Sports

 

Introduction

 

Physiology is the academic study of the various processes, systems and functions of the human body as influenced by the performance of physical activity. The physiology of exercise is a broad concept that addresses the central issue as to how the body adapts itself to the demands of physical activity. Maintaining adequate levels of physical activity is known to preserve health status and functional independence as individuals grew older. However, the relationship between determinants of physical activity and physiological factors underlying mobility is yet not clear. Various factors determining the components of physical fitness are: muscle fibre spectrum, muscle cross-section, maximal oxygen uptake, mobility of the nervous system, exercise economy, genetics, hydration etc.

 

Main differences in Physical and Physiological Parameters

 

(1) Muscular Strength: Females have less muscular mass as compared to males. Males convert more of their caloric intake into muscles while females tend to convert caloric intake more into fat deposit. Thus men are physically stronger than females.

 

(2) Endurance: Males have large lung volume (i.e., more vital capacity), moreover higher oxygen carrying capacity. This causes more endurance in males.

 

(3) Sensitivity: It is a fact that females are more sensitive to smell as compared to males.

 

(4) Flexibility and Speed: Females are more flexible as compared to males whereas males have more speed ability.

 

(5) Skin: Males have hard, more prone to redness and darker sin, whereas skin of females is soft, sensitive and fair.

 

(6) Age and Gender: Physical fitness is related to age and gender. It depends on gender difference. Male has more strength and endurance as compared to female and females dominate in flexibility and co-ordination dominating physical activities.

 

(7) Blood Components: Females usually have lower Blood Pressure than males. Males have higher concentration of androgens while females have higher level of estrogens. Females have more WBC (While Blood Cells), Granulocytes and Lymphocytes; thus females have better immune system than males.

 

(8) Skeleton Difference: Female skeleton is generally lighter, smooth and delicate than males, female pelvis is wider. Males have heavier, longer and stronger bones.

 

(9) Weight: Males are heavier (about 15% more), i.e., males have more weight as compared to females of same height.

(10) Height and Waist: Males are taller than females (about six inches). On average men have large waist whereas women have wider hips as compared to men.

 

Physiological Factors Determining Strength

 

(1) Gender: Males have more strength as compared to females due to bigger and longer muscle length in males.

(2) Adequate Energy: The muscular movements need sufficient energy. Greater number of mitochondria in muscle fibers produces more energy and stronger and longer muscular contraction.

(3) Muscular Contraction: Concentric and Eccentric muscular contraction regulates our muscular action in controlled manner. It helps in accuracy and efficiency of movement, thus helps in strength development.

(4) Muscle Length: Every muscle is of different size. Long muscles have more potential of strength as compared to small muscles.

(5) Neuromuscular Responses: The neuromuscular responses are the impulses produced by nervous system to control muscular contractions. The intensity of neuromuscular responses (impulses) determine strength.

(6) Muscle Covering: The muscle fibers covering 'sarcolemma’ binds the muscle fibres to work together. The sarcolemma covering increases the muscle cross-sectional area and helps in strength component.

(7) Body Weight: It is fact that the individuals who are heavier are stronger than the individuals who are thin/ lighter. The heavier weightlifters lift the heavier weight. Hence, body weight determines the strength of an individual.

(8) Age: Strength of muscles is maximum between 20 to 40 years of age and it gradually weakens.

 

Very Short Answer Type Questions (1 Mark)

 

Q. What is physical fitness?

 

Ans. Dr. K.L. Anderson has defined physical fitness as “The ability for respiration and circulation to recover from a standard work load.”

 

Q. Define physiology and sports.

 

Ans. Physiology is the study of how the human body functions. It applies the concept of exercise physiology for training the athlete and enhancing the athlete's sports performance.

 

Q6. What do you mean by ageing?

 

Ans. Ageing is an inevitable and extremely complex, multi-factorial process. It is characterized by the progressive degeneration of organ systems and tissues. It is largely determined by genetics and influenced by a wide range of environmental factors such as diet, exercise, exposure to micro-organism, pollutants etc.

 

Q. How much blood is found in a normal human being?

 

Ans. The body of an adult contains about 5 to 7 L of blood which weighs 1/3rd of the total body weight. 

 

Q. What is the systolic pressure exerted by the blood? 

 

Ans. The pressure exerted by the blood on the walls of the blood vessels is called blood pressure'. It has two limits, i. e. The upper limit called systolic pressure and the lower limit called the diastolic pressure. Systolic pressure is recorded when the blood is ejected into the arteries during ventricular contraction.

 

Q. Explain the effects of ageing on lean body weight and BMR.

 

Ans. With ageing, there is increase in accumulated fat and has ability to release stored fatty acids from adipose tissues for energy decreases. Similarly, lean body weight also decreases due to decrease in muscle size and decline in calcium and phosphorous content of the bones. BMR or Basal Metabolic Rate also reduces with ageing due to the decline in lean body weight.

 

Q. What is flexibility?

 

Ans. Up to some extent, flexibility also determines the speed. In fact, good flexibility allows maximum range of movement without much internal resistance. Flexibility also enables complete utilization of explosive strength.

 

Q. State any one physiological factor which determines flexibility.

 

Ans. Internal Environment: Internal environment of the athlete influences the flexibility. For example, 10 minutes in a warm bath increases body temperature and flexibility whereas, 10 minutes stay outside in 10°C reduces body temperature and flexibility.

 

Q4. What is cardiac output?

 

Ans. Cardiac output is the amount of blood pumped by the heart in one minute. It is measured in litre/minute. Cardiac output is a product of stroke volume and heart rate. If either heart rate or stroke volume increases or both, the cardiac output increases also.

 

Q5. What do you mean by stroke volume?

 

Ans. Stroke volume is the amount of blood ejected per beat from the left ventricle. It is measured in ml/beat. Stroke volume increases proportionally with exercise intensity.

 

Q8. What do you mean by oxygen intake and oxygen uptake?

 

Ans. Oxygen intake: It is the amount of oxygen which can be taken by the lungs from atmosphere. 

Oxygen uptake: The amount of oxygen which can be observed and consumed by the working muscles from the blood is called oxygen uptake.

 

 

Short Answer Type Questions (3 Marks) 

 

Q1. Discuss the effect of ageing on the size and strength of muscles.

 

Ans. When an individual gets older, there is a decline in muscle size. There is a decrease in muscle mass and increase in overall body fat. Due to decrease in muscle size, the strength of the muscles also decreases. The decrease in strength gradually occurs during the age of 35 to 45 years. However, even at the age of 60 the decrease in strength does not appear to exceed 20% of an individual’s maximum strength.

 

Q2. Elaborate the effect of ageing on bone density.

 

Ans. With the advancement of age the bone density decreases. It means that the elderly persons especially those over 40 years of age, are more prone to bone injury than young persons. In fact, it is due to decrease in various minerals such as calcium and phosphorus, found in bones. The bones become less dense and more porous. The decreasing process of these minerals begins in the early forties.

 

Q13. Elaborate the effect of ageing on respiratory system.

 

Ans. A number of research studied show that pulmonary function is impaired with advancing age. The airways and lung tissues become less elastic. They become less efficient. There is decreased oxygen uptake and oxygen exchange. The muscles of the rib cage become weak. Hence, the ability to breathe deeply is reduced. Pulmonary oxygen is reduced which leads to decrease endurance with shortness of breath and fatigue. It can be said that tidal volume, vital capacity, lung capacity are decreased, whereas residual volume is increased.

 

Q14. Elaborate the effects of ageing on nervous system.

 

Ans. A number of research studies indicate that reaction time and movement time slow down with increasing age. The brain’s weight, the size of its network and its blood flow decreases with the age. However, the brain adapts to these changes, growing new patterns of nerve endings. To recall memories becomes slow.

 

Q15. How do regular exercises during the process of ageing reduce loss of muscle mass?

 

Ans. Muscle mass decreases with advancing age. Aging has a negative effect on metabolism. Regular exercise decreases the loss of lean body mass and drop in the metabolic rate. Regular exercise also reduces the accumulation of fats.

 

Q17. How does Regular Exercise help in reducing cholesterol level?

 

Ans. Regular exercise reduces the cholesterol level in our blood. The level of cholesterol in blood has a direct link with the blood pressure. So, light exercises are given to a patient of blood pressure, which decreases his cholesterol level in blood. In fact, exercises have a two-way effect on cholesterol. Firstly, exercises decrease the level of LDL (Low Density Lipo-protein) and increases the level of HDL (High Density Lipo-protein). It means that exercise decreases LDL (Bad cholesterol) and increases HDL (good cholesterol).

 

Q1. Explain any 3 physiological factors determining strength.

 

Ans. Size of muscles: The strength of the muscle largely depends upon the size of the muscle. It is a well-known fact that bigger and larger muscles can produce more force. The force produced by the same size of muscle in males and females is approximately the same but males are found to be stronger because they have larger muscles and bigger muscles in comparison to females.

 

2. Body weight: It is also a well-known fact that the individuals who are heavier are stronger than the individuals who are lighter. There is a positive correlation between body weight and strength among international weightlifters. The heavier weightlifters lift the heavier weight. So, body weight also determines the strength of an individual.

 

3. Intensity of the nerve impulse: A muscle is composed of a number of motor units. The total force of the muscle depends on the number of contracting motor units. Whenever, a stronger nerve impulse from central nervous system excites more number of motor units, the muscles will contract more strongly or it can said that the muscle will produce more force or strength. So, the intensity of the nerve impulse also determines the amount of strength.

 

Q2. Discuss any three physiological factors determining speed.

 

Ans. 1. Mobility of the nervous system: Our muscles contract and relax at maximum possible speed such as in sprinting events. This rapid contraction and relaxation of muscles is made possible by rapid excitation and inhibition of the concerned motor centres.

 

This is called the mobility of the nervous system. The nervous system can maintain this rapid excitation and inhibition only for a few seconds after which the excitation spreads to the neighboring centers causing tension in the entire body. This results in decrease in speed.

 

2. Muscle composition: The muscles, which have more percentage of fast twitch fibres contract with more speed in comparison to the muscles which have lower percentage of fast twitch fibres. In fact, the muscles composition is genetically determined and cannot be changed by training. Different muscles of the body have different percentage of fast twitch fibres. So, different parts of body have different speed performance.

 

3. Flexibility: Up to some extent, flexibility also determines the speed. In fact, good flexibility allows maximum range of movement without much internal resistance. Flexibility also enables complete utilization of explosive strength.

 

Q3. Elaborate any three physiological factors determining endurance.

 

Ans. 1. Lactic acid tolerance: The ability to tolerate to higher concentration of lactic acid is a significant factor in determining an aerobic capacity. The lactic acid tolerance is important for activities that last for about 40 seconds or more. The lactic acid tolerance capacity can be improved through training. So, it can help in improving endurance performance.

 

2. Movement economy: The economical movements are significant for endurance performance. A runner, who can run at a given race with less energy expenditure can continue with the same speed for longer duration. A good technique in endurance spots can save energy. For example, in swimming 20 to 30 percent of the energy can be saved if the movements are correct. For economical movements, the good runners raise their centre of gravity less high, so, their unnecessary movements are less.

 

3. Muscle composition: There are two basic types of muscle fibres such as slow twitch fibres and fast twitch fibres. The slow twitch fibres are best used for aerobic activities or endurance activities. They produce small levels of force for long periods of time and that is why, they are better suited for endurance activities.

 

Q4. Discuss any three physiological factors determining flexibility.

 

Ans. 1. Age and Gender: It is a well-known fact that flexibility decreases with the advancement of age. However, it is trainable. It can be enhanced with the help of training as strength and endurance are enhanced. Gender also determines the flexibility. Females tend to be more flexible than males.

 

2. Interval environment: Internal environment of the athlete influences the flexibility. For example 10 minutes in a warm bath increases body temperature and flexibility whereas, 10 min. stay outside in 10°C reduces body temperature and flexibility.

 

3. Previous injury: Injuries to connective tissues and muscles can lead to thickening of fibre tissues on the affected area. Fibrous tissues are less elastic and can lead to limb shortening and ultimately lead to reduced flexibility.

 

Q5. Discuss any three immediate effects of exercise on cardiovascular system.

 

Ans. 1. Increase in heart rate: Generally the resting heart rate of an adult remains at 72 beats per minute. The elite endurance athletes usually have 28 to 40 beats per minute. Even before the beginning of exercise the heart rate increases in anticipation. It is known as anticipatory response. When an individual starts exercise his heart rate increases as per the intensity and duration of the exercise.

 

2. Increase in stroke volume: Stroke volume is the amount of blood ejected per beat from the left ventrical. It is measured in ml/beat. Stroke volume increases proportionally with exercise intensity. In untrained individuals the stroke volume at rest remains at 50 to 70 ml/beat. It increases up to 110 to 130 ml/beat during intense exercise. The stroke volume of experienced athletes at rest remains at 90 to 110 ml/beat. It increases up to 15 to 22 ml/beat during intense exercise.

 

3. Increase in cardiac output: Cardiac output is the amount of blood pumped by the heart in one minute. It is measured in litre/minute. Cardiac output is a product of stroke volume and heart rate. If either heart rate or stroke volume increases or both, the cardiac output increases also.

 

Q6. Discuss any three effects of exercise on respiratory system.

 

Ans. 1. Increase in residual air volume: Residual air is the amount of air, which is left in the lungs after exhalation. If an individual performs regular exercise, his residual air capacity increases in comparison to an individual who does not perform regular exercise.

 

2. Increase in size of lungs and chest: When a person performs exercise regularly, he requires more amount of 02. He inhales more amount of air during exercise. Consequently, his lungs and chest are exercised. After some period, the size of his lungs and chest increases.

 

3. Increase in vital air capacity: It is the amount of air which an individual can inhale and exhale with maximum effort. Its capacity varies from 3500 cc to 4500 cc in a normal adult. It is the sum of tidal volume, inspiratory reserve volume and expiratory reserve volume. Due to regular exercise its capacity increases up 5500 cc.

 

Q7. Discuss any three effects of exercise on circulatory system.

 

Ans. 1. Increase in number and efficiency of capillaries: With the regular exercise, the efficiency and number of capillaries are increased. The unused and new capillaries become efficient and nourish the various cells efficiently.

 

2. Increase in number of RBC: The number of RBC (Red Blood Cells) increases when exercises are taken on regular basis. These RBC’s are the carriers of nutrients, including haemoglobin and 02 to the muscles.

 

3. Delay in fatigue: Regular exercise delays the fatigue in an individual. Fatigue is felt due to the formation of lactic acid and phosphate in the muscles. These waste products are easily and very fastly removed from muscles, if exercises are performed regularly. Even muscles can bear the formation of lactic acid, so it delays the fatigue.

 

Q8. Elaborate any three physiological changes in human body due to ageing.

 

Ans. 1. Changes in nervous system: A number of research studies indicate that reaction time and moment time slow down with increasing age. Their brain’s weight, the size of its network and its blood flow decreases with the age. However, the brain adapts to these changes, growing- new patterns of nerve endings. To recall memories becomes slow.

 

2. Changes in the gastrointestinal system: With increasing age, there is a reduction in the production of hydrochloric acid, digestive enzymes and salina. These changes may result in delayed emptying of stomach, impaired swallow. The breakdown and absorption of foods may also be impaired. The liner becomes less efficient in metabolising drugs and repairing damaged liver cells.

 

3. Change in flexibility: The elasticity of tendons, ligaments and joints capsules is decreased with ageing. The elderly persons lose 8- 10 cm of low back and hip flexibility according to a research study. The range of moment is restricted as the age increases.

 

Q9. Discuss the physiological changes in senses due to ageing process. Briefly explain the role of exercise on ageing process.

 

Ans. Changes in Senses: With advancing age, the senses such as vision, hearing, taste, smell and touch etc. may become less acute. Vision and hearing are most affected by ageing. The main changes in senses are listed below:

 

(a) Change in vision

(b) Change in hearing

(c) Changes in taste

(d) Change in smell

 

Role of regular exercise on ageing process: It is a well-known fact that no amount of physical activity or exercise can stop the ageing process but a moderate amount of regular exercise can minimize the various physiological effects due to ageing. It can be said that regular exercise is the most powerful, supplement to slowdown the ageing process. It can slowdown and even in some cases it can reverse the most common signs of ageing such as muscle and boneless, increased body fat, memory and cognitive decline, decreased metabolism, decreased flexibility and decreased blood flow etc.

 

Q10. Discuss the long term effect of exercise?

 

Ans. 1. Increase in blood volume: The regular exercise increases the blood volume. In fact, there is an increase in plasma volume which enhance the blood volume. In addition, the body produces a greater number of red blood cells.

 

2. Quicker recovery rate: Regular exercise quickens the recovery rate. A train athlete’s heart rate becomes normal earlier in comparison to a beginner. Rate of respiration also becomes normal quickly. Therefore, the recovery becomes fast.

 

3. Reduced risk of heart diseases: Regular exercise gradually reduces stress-related hormones from circulating in the blood. This increases the blood vessel path, which in turn lowers the risk for the buildup of plaque that can lead to coronary heart diseases. Hence, exercises reduce the risk of heart diseases.

 

Long Answer Type Questions (5 Marks)

 

Q1. Describe physiological factors determining component of physical fitness.

 

Ans. Physiological factors determining components of physical fitness are:

 

(ì) Muscular strength: This is the maximum force or tension 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 in 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 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.

(vì) 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.

 

Q2. Discuss any five effects of exercise on respiratory system.

 

Ans. 1. Decrease in rate of respiration: It is certain that when a beginner starts exercise, his rate of respiration increases. But when the same individual performs exercises daily, his rate of respiration decrease in comparison to the beginning stage at rest.

 

2. Avoid second wind: For a beginner, the stage of second wind is, indeed, a crucial stage. But for a regular exerciser, it is hardly felt. Sometimes, a well experienced athlete does not feel it in his course of activity.

 

3. Unused alveoles become active: Regular exercise activates the unused alveoles, because much amount of 09 is required in vigorous and prolonged exercise of daily routine. The passive alveolus become active.

 

4. Increase in residual air volume: Residual air is that amount of air, which is left in the lungs after exhalation. If an individual performs regular exercise, his residual air capacity increases in comparison to an individual who does not perform regular exercise.

 

5. Increase in size of lungs and chest: When a person performs exercise regularly, he requires more amount of 02. He inhales more amount of air during exercise. Consequently, his lungs and chest are exercised. After some period, the size of his lungs and chest increases.

 

Q3. Enumerate any five effects of exercise on circulatory system.

 

Ans. 1. Increase in number and efficiency of capillaries: With the regular exercise, the efficiency and number of capillaries are increased. The unused and new capillaries become efficient and nourish the various cells efficiently.

 

2. Increase in number of RBC: The number of RBC (Red Blood Cell) increases when exercises are taken on regular basis. These RBCs are the carriers of nutrients, including haemoglobin and 02 to the muscles.

 

3. Increase in number of WBC: It has also been noted that regular exercise increases the number of WBC (White Blood Cells).

 

4. Delay in Fatigue: Regular exercise delays the Fatigue in an individual. Fatigue is felt due to the formation of lactic acid and phosphate in the muscles. These waste products are easily and very fastly removed from muscles, if exercises are performed regularly. Even muscles can bear the formation of lactic acid, so it delays the fatigue.

 

5. Fast recovery period: Recovery period becomes fast. An experienced athletics’ heart rate becomes normal earlier in comparison to an inexperienced or a beginner. Same in the case of respiration, it also becomes normal rapidly in case of experienced athlete.

 

Q4. Elucidate any 5 physiological changes due to ageing process.

 

Ans. 1. Changes in metabolism and body composition: With advancement of age our body needs less energy and the metabolism slows down. Consequently there is an increase in the accumulation of body, fat and lean body weight (bones, ligaments, tissues, tendons, muscles and water) decreases. The metabolic rate decreases gradually with the increasing age. It also results in more accumulation of body fat.

 

2. Changes in nervous system: A number of research studies indicate that reaction time and moment time slow down with increasing age. They brain’s weight, the size of its network and its blood flow decreases with the age. However, the brain adopts to these changes growing new patterns of nerve endings. To recall memories becomes slow.

 

3. Changes in the gastrointestinal system: With increasing age, there is a reduction in the production of hydrochloric acid, digestive enzymes and saliva. These changes may result in delayed emptying of stomach, impaired swallowing. The breakdown and absorption of foods may also be impaired. The liver becomes less efficient in metabolizing drugs and repairing damaged liver cells.

 

4. Changes in urinary system: As the age, the mass of the kidneys decreases. This leads to reduction in the rate of blood filtration by the kidneys. The capacity of bladder decreases and there is an increase in residual urine. These changes increase the changes of urinary infection.

 

5. Changes in flexibility: The elasticity of tendons, ligaments and joint capsules is decreased with ageing. The elderly persons lose 8- 10 cm of lower back and hip flexibility according to a research study. The range of movement is restricted as the age increases.

 

Q5. Elaborate the role of regular exercise on ageing process.

 

Ans. 1. Reduces the loss of muscle mass: Muscle mass decreases with advancing age. Ageing has a negative effect on metabolism. Regular exercise decreases the loss of lean body mass and drop is the metabolic rate. Regular exercise also reduces the accumulation of fats.

 

2. Helps in maintaining bone density: Bone density decreases with age. It usually leads to fracture and osteoporosis. Physical exercise helps to maintain bone mass and prevents osteoporosis. Resistance exercise, stimulates bone growth. Research studies show that the ageing persons can increase their bone density with the help of regular exercise.

 

3. Improves muscular strength: Ageing process does not hinder the individual’s ability to enhance muscle strength. Regular exercise increases the strength of muscles. As a matter of fact, exercises increases the size of muscles which ultimately increases muscular strength.

 

4. Enhance the capacity of lungs: Regular exercise enhances the capacity of lungs. It reduces the loss of elasticity of the lungs and chest wall. It also plays a key role in keeping the lungs strong. Regular exercise increase oxygen uptake and oxygen exchange.

 

5. Improves flexibility: Regular exercise improves the elasticity of tendons, ligaments and joint capsules. Exercise decreases the stiffness of joints. In this way, there is improvement in flexibility.

 

 

 

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