The human body has a number of systems that supply energy. This enables the body to function to the most efficient level to accomodate the functions of the body from basic movement to the blood circulation. The body requires energy to excert any physical force to engage in an activity. The body has a complex storage of energy that it only becomes energy when needed and is not stored in a solid manner. Our bodies have the advantage of not having to carry energy in whole but rather, the usage of chemical bonds and reaction towards a few triggers(heat in particular) will provide this.
If the ATP is used up, it turns into ADP (adenosine diphosphate) and because it is in this state, it does not provide energy. ADP however, is not a waste product and can be reused and this gives us the ability to function with a limited amount of ATP through the process of rebuilding and resynthesis.
Introducing the Systems
There are three systems that rebuild and create ATP and this is done according to the physical needs of the body- The Alactacid System (ATP/PC), Lactic Acid System (Glycolytic)and the Aerobic System(Oxygen). The body uses one or a combination to make sure our energy needs are met and the continually resynthesised ATP provides us energy to power and bodily functions to perform additional work regardless of duration and intenisty. The systems are generally called energy pathways becayse they supply ATP but use different processes. Alactacid and Lactic Acid Systems are both called anaerobic pathways because they do not require oxygen for the resynthesis of ATP through oxygen. The Aerobic system produced using this system relies on the availability of sufficient oxygen in the cells.
Alactacid System
The residual supplies of ATP in the body aare very limited and the body is capable for one explosive muscular contraction (a jump or a sprint). One explosive movement causes the ATP molecule to 'split'. Providing energy for muscular contractions. Further muscular work is relied on the molecule Creatine Phosphate(CP) which is also stored in the muscle tissues. The CP is split so that the ADP gains a phosphate molecule and ATP can be broken down again once reformed. However, CP lasts for only 10-12 seconds and take approximately 2 minutes to be restored.
The system allows immediate supply of ATP molecules whether or not oxygen is available. The supply is mostly provided by CP which has approcimately 5 times greter energy than ATP. Since there is a high demand of ATP, CP is used as a compensation for the required phosphate.The usage of this system would be according to the physical demand usually created for a sustained, naximal or near maximal work as a result.
ATP supplies exhaust after 2 seconds and the CP in 10-12 seconds which, if the body attempts anything longer than the duration will mean fatigue as it is caused by the inability for the system to continually resynthesise. Heat is also produced during the muscular contractions. The system recovers quickly from exercise- in 2 minutes ATP and CP supplies would be restored and 50% of creatine phosphate is recovered during the first 30 seconds.
Lactic Acid System
After 10 -12 seconds, the CP supplies will be completely exhausted and even oxygen is not sufficiently available even thoughtthere is an increase in breathing rate because of effort. Note that it takes time for the blood to transport oxygen in the lungs. This system turns to the glucose supply called glycogen. These are found in the pancreas, liver and the muscle and immediate sugars can be attained through the bloodstream as it naturally circulates with the blood. This process is called glycolysis and is much more abundant than CP. The process of the usage of glycogen is called aerobic glycolysis- glucose is broken down in the absence of oxygen to produce energy.
Carbohydrates is the only fuel that can be used by the Lactic Acid System and exists in two forms:
-Glucose in the blood
-Storage form called glycogen
The Lactic Acid System provides ATP quickly but also consumes large amounts of glucose and the duration of the system is dependent on the intensity of the activity. Maximal effort will cause exhaustion in 30 seconds. An effort of around 80% will last at 4 minutes and probably longer for moderate intensity activity. If the glucose have all been used up and the body is pushing for more energy and more time is needed for recovery, this will cause levels of lactic acid to build up within the muscle cells and thus fatigue.
Lactic acid can affect the person's performace depending on the rate of removal. The more intense the activity is, the higher the build up. The body produces this because carbohydrates are being metabolised instead of fat. High levels of lactic acid will prevent the muscles to contract and this causes rapid deterioration. The rate of recovery will be around 30 mins where the lactate acid accumulated will be converted back to glycogen in the liver.
Aerobic System
Continuous physical activity will require the precence of oxygen to ensure the continuation of muscular contraction. Oxygen is not immediately abundant and is gradual in supplying the muscle cells with oxygen-enriched blood. This third energy pathway is the predominant supplier of ATP. Aerobic metabolism is the breakdown of fuel in the presence of oxygen to produce ATP and this is the process of fuel degradion as glucose, fat and protein (in some cases) are broken down for energy source. -This system can use a range of energy sources initially starting with carbohydrates then fat (if activity goes on for an hour).
The aerobic system is extremely efficient in the metabolism of fuel and provision of energy. The system is able to produce a relatively bigger amount of moles than the Lactic Acid System. The total amount of glycogen in the body is 350 grams and is sufficient for 12 hours or rest or one hour of hard work. In exercises such as netball or football, it will last for approximately six hours and for marathon runners it would only last for two.
Large supplies of fat being produced used jointly and sparingly will ensure that the body can operate for long periods of time. however, because the aeorbic system is so versatile in fule usage, the fatigue is caused by slow twitch muscles that do most of the work. The glycogen level in the fibres will decrease dramatically and when it runs out, the muscle tires. Fatigue is also a result of the exhasustion of carbohydrate and the reliance of the energy fat. - Increasing the body temperature and rate of respiration.
Biproducts such as carbon dioxide and water are not necessarily harmful as carbon dioxide is exhaled. The rate of recovery would be dependent on the duration of usage. If the glycogen storages have not been depleted, it will take a much less period compared to the it being used for hours then, it may take days for full recovery.
The body stores it's energy chemically and is measured in kilojoules(kj). Foods have different amounts of energy- fat having the highest energy content compared to proteins and carbohydrates. The chemical potential energy in food must be converted to mechanical energy (kinetic or movement energy) and the energy is used to drive muscular contraction during movement.
The process
ATP production consists of a large moelcule called adenosine (A) and three smaller melocules called phosphates (P). Each of the phosphates is held together by high energy bonds. When the last phosphate is detatched, it expels heat and energy and the energy stored in bonds between phosphates is transferred to the cells. In muscle cells, ATP allows muscle fibres to contract and makes movements possible.
 |
| My translation of ATP production |
Introducing the Systems
There are three systems that rebuild and create ATP and this is done according to the physical needs of the body- The Alactacid System (ATP/PC), Lactic Acid System (Glycolytic)and the Aerobic System(Oxygen). The body uses one or a combination to make sure our energy needs are met and the continually resynthesised ATP provides us energy to power and bodily functions to perform additional work regardless of duration and intenisty. The systems are generally called energy pathways becayse they supply ATP but use different processes. Alactacid and Lactic Acid Systems are both called anaerobic pathways because they do not require oxygen for the resynthesis of ATP through oxygen. The Aerobic system produced using this system relies on the availability of sufficient oxygen in the cells.
Alactacid System
The residual supplies of ATP in the body aare very limited and the body is capable for one explosive muscular contraction (a jump or a sprint). One explosive movement causes the ATP molecule to 'split'. Providing energy for muscular contractions. Further muscular work is relied on the molecule Creatine Phosphate(CP) which is also stored in the muscle tissues. The CP is split so that the ADP gains a phosphate molecule and ATP can be broken down again once reformed. However, CP lasts for only 10-12 seconds and take approximately 2 minutes to be restored.
The system allows immediate supply of ATP molecules whether or not oxygen is available. The supply is mostly provided by CP which has approcimately 5 times greter energy than ATP. Since there is a high demand of ATP, CP is used as a compensation for the required phosphate.The usage of this system would be according to the physical demand usually created for a sustained, naximal or near maximal work as a result.
ATP supplies exhaust after 2 seconds and the CP in 10-12 seconds which, if the body attempts anything longer than the duration will mean fatigue as it is caused by the inability for the system to continually resynthesise. Heat is also produced during the muscular contractions. The system recovers quickly from exercise- in 2 minutes ATP and CP supplies would be restored and 50% of creatine phosphate is recovered during the first 30 seconds.
Lactic Acid System
After 10 -12 seconds, the CP supplies will be completely exhausted and even oxygen is not sufficiently available even thoughtthere is an increase in breathing rate because of effort. Note that it takes time for the blood to transport oxygen in the lungs. This system turns to the glucose supply called glycogen. These are found in the pancreas, liver and the muscle and immediate sugars can be attained through the bloodstream as it naturally circulates with the blood. This process is called glycolysis and is much more abundant than CP. The process of the usage of glycogen is called aerobic glycolysis- glucose is broken down in the absence of oxygen to produce energy.
Carbohydrates is the only fuel that can be used by the Lactic Acid System and exists in two forms:
-Glucose in the blood
-Storage form called glycogen
The Lactic Acid System provides ATP quickly but also consumes large amounts of glucose and the duration of the system is dependent on the intensity of the activity. Maximal effort will cause exhaustion in 30 seconds. An effort of around 80% will last at 4 minutes and probably longer for moderate intensity activity. If the glucose have all been used up and the body is pushing for more energy and more time is needed for recovery, this will cause levels of lactic acid to build up within the muscle cells and thus fatigue.
Lactic acid can affect the person's performace depending on the rate of removal. The more intense the activity is, the higher the build up. The body produces this because carbohydrates are being metabolised instead of fat. High levels of lactic acid will prevent the muscles to contract and this causes rapid deterioration. The rate of recovery will be around 30 mins where the lactate acid accumulated will be converted back to glycogen in the liver.
Aerobic System
Continuous physical activity will require the precence of oxygen to ensure the continuation of muscular contraction. Oxygen is not immediately abundant and is gradual in supplying the muscle cells with oxygen-enriched blood. This third energy pathway is the predominant supplier of ATP. Aerobic metabolism is the breakdown of fuel in the presence of oxygen to produce ATP and this is the process of fuel degradion as glucose, fat and protein (in some cases) are broken down for energy source. -This system can use a range of energy sources initially starting with carbohydrates then fat (if activity goes on for an hour).
The aerobic system is extremely efficient in the metabolism of fuel and provision of energy. The system is able to produce a relatively bigger amount of moles than the Lactic Acid System. The total amount of glycogen in the body is 350 grams and is sufficient for 12 hours or rest or one hour of hard work. In exercises such as netball or football, it will last for approximately six hours and for marathon runners it would only last for two.
Large supplies of fat being produced used jointly and sparingly will ensure that the body can operate for long periods of time. however, because the aeorbic system is so versatile in fule usage, the fatigue is caused by slow twitch muscles that do most of the work. The glycogen level in the fibres will decrease dramatically and when it runs out, the muscle tires. Fatigue is also a result of the exhasustion of carbohydrate and the reliance of the energy fat. - Increasing the body temperature and rate of respiration.
Biproducts such as carbon dioxide and water are not necessarily harmful as carbon dioxide is exhaled. The rate of recovery would be dependent on the duration of usage. If the glycogen storages have not been depleted, it will take a much less period compared to the it being used for hours then, it may take days for full recovery.
No comments:
Post a Comment