question: How are muscles supplied with oxygen during exercise?
comment: The right ventricle of the heart pumps blood into the lungs, where it releases carbon dioxide and absorbs oxygen. And then goes back to the heart and is pumped out by the left ventricle enter the arteries, and from there into the capillary beds. These capillary beds run through everything that needs to be serviced, including muscles. Then the blood, depleted of oxygen and rich in carbon dioxide, flows from the capillary beds into the veins and back to the heart again. So the muscles merely work, producing carbon dioxide that they released into the bloodstream through those capillary beds, and absorbing oxygen through those capillary beds.
passages: The cellular respiration process that converts food energy into ATP (a form of energy) is largely dependent on oxygen availability. During exercise, the supply and demand of oxygen available to muscle cells is affected by duration and intensity and by the individual's cardiorespiratory fitness level. Three exercise energy systems can be selectively recruited, depending on the amount of oxygen available, as part of the cellular respiration process to generate the ATP for the muscles. They are ATP, the anaerobic system and the aerobic system.
  
  Section::::Adenosine triphosphate.
   Section::::Physiology.:Aerobic and anaerobic muscle activity.
   The basic mechanism for fermentation remains present in all cells of higher organisms. Mammalian muscle carries out the fermentation that occurs during periods of intense exercise where oxygen supply becomes limited, resulting in the creation of lactic acid. In invertebrates, fermentation also produces succinate and alanine.
   All muscle fibres in a motor unit are of the same fibre type. When a motor unit is activated, all of its fibres contract. In vertebrates, the force of a muscle contraction is controlled by the number of activated motor units.
   Vigorous physical activity (such as exercise or hard labor) increases the body's demand for oxygen. The first-line physiologic response to this demand is an increase in heart rate, breathing rate, and depth of breathing.
   British physiologist Archibald Hill introduced the concepts of maximal oxygen uptake and oxygen debt in 1922. Hill and German physician Otto Meyerhof shared the 1922 Nobel Prize in Physiology or Medicine for their independent work related to muscle energy metabolism. Building on this work, scientists began measuring oxygen consumption during exercise. Notable contributions were made by Henry Taylor at the University of Minnesota, Scandinavian scientists Per-Olof Åstrand and Bengt Saltin in the 1950s and 60s, the Harvard Fatigue Laboratory, German universities, and the Copenhagen Muscle Research Centre among others.
   Section::::Storage.
   The heart functions as a pump in the circulatory system to provide a continuous flow of blood throughout the body. This circulation consists of the systemic circulation to and from the body and the pulmonary circulation to and from the lungs. Blood in the pulmonary circulation exchanges carbon dioxide for oxygen in the lungs through the process of respiration. The systemic circulation then transports oxygen to the body and returns carbon dioxide and relatively deoxygenated blood to the heart for transfer to the lungs.
   British physiologist, Archibald Hill introduced the concepts of maximal oxygen uptake and oxygen debt in 1922. German physician, Otto Meyerhof and Hill shared the 1922 Nobel Prize in Physiology or Medicine for their independent work related to muscle energy metabolism. Building on this work, scientists began measuring oxygen consumption during exercise. Notable contributions were made by Henry Taylor at the University of Minnesota, Scandinavian scientists Per-Olof Åstrand and Bengt Saltin in the 1950s and 60s, the Harvard Fatigue Laboratory, German universities, and the Copenhagen Muscle Research Centre among others.
   Cardiac muscle undergoes aerobic respiration patterns, primarily metabolizing lipids and carbohydrates. Oxygen from the lungs attaches to haemoglobin and is also stored in the myoglobin, so that a plentiful supply of oxygen is available. Lipids, and glycogen are also stored within the sarcoplasm and these are broken down by mitochondria to release ATP. The cells undergo twitch-type contractions with long refractory periods followed by brief relaxation periods when the heart fills with blood for the next cycle.
  
  Section::::Electrical conduction.
   One component of the heart-lung machine is the oxygenator. The oxygenator component serves as the lung, and is designed to expose the blood to oxygen and remove carbon dioxide. It is disposable and contains about 2–4 m² of a membrane permeable to gas but impermeable to blood, in the form of hollow fibers. Blood flows on the outside of the hollow fibers, while oxygen flows in the opposite direction on the inside of the fibers. As the blood passes through the oxygenator, the blood comes into intimate contact with the fine surfaces of the device itself. Gas containing oxygen and medical air is delivered to the interface between the blood and the device, permitting the blood cells to absorb oxygen molecules directly.
   Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.
  
  Section::::History.
  
  Section::::History.:Early experiments.
   Section::::History.
   The main function of striated muscle tissue is to create force and contract. These contractions will either pump blood throughout the body (cardiac muscle) or powers breathing, movement or posture (skeletal muscle).
  
  Section::::Function.:Contractions.
   High energy phosphates are stored in limited quantities within muscle cells. Anaerobic glycolysis exclusively uses glucose (and glycogen) as a fuel in the absence of oxygen, or more specifically when ATP is needed at rates that exceed those provided by aerobic metabolism. The consequence of such rapid glucose breakdown is the formation of lactic acid (or more appropriately, its conjugate base lactate at biological pH levels). Physical activities that last up to about thirty seconds rely primarily on the former, . Beyond this time both aerobic and anaerobic glycolysis-based metabolic systems begin to predominate.
   Three methods can synthesize ATP:
  
  BULLET::::- ATP–CP system (phosphogen system) – This system is used for durations of up to 10 seconds. The ATP–CP system neither uses oxygen nor produces lactic acid if oxygen is unavailable and is thus said to be alactic anaerobic. This is the primary system behind very short, powerful movements like a golf swing, a 100 m sprint or powerlifting.
   Oxygen is a component of many organic and inorganic molecules within the plant, and is acquired in many forms. These include: O and CO (mainly from the air via leaves) and HO, NO, HPO and SO (mainly from the soil water via roots). Plants produce oxygen gas (O) along with glucose during photosynthesis but then require O to undergo aerobic cellular respiration and break down this glucose to produce ATP.
  
  Section::::Functions of nutrients.:Macronutrients (primary).
  
  Section::::Functions of nutrients.:Macronutrients (primary).:Nitrogen.
   In a normal resting state the work of breathing constitutes about 5% of the total body oxygen consumption. It can increase considerably due to illness or constraints on gas flow imposed by breathing apparatus, ambient pressure, or breathing gas composition.
  
  Section::::Mechanism of breathing.
  
  The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work.
   Oxygen storage
  
  Methods of oxygen storage for subsequent use span many approaches, including high pressures in oxygen tanks, cryogenics, oxygen-rich compounds and reaction mixtures, and chemical compounds that reversibly release oxygen upon heating or pressure change. O is the second most important industrial gas.
  
  Section::::Air.
   The heart functions as a pump and acts as a double pump in the cardiovascular system to provide a continuous circulation of blood throughout the body. This circulation includes the systemic circulation and the pulmonary circulation. Both circuits transport blood but they can also be seen in terms of the gases they carry. The pulmonary circulation collects oxygen from the lungs and delivers carbon dioxide for exhalation. The systemic circuit transports oxygen to the body and returns relatively de-oxygenated blood and carbon dioxide to the pulmonary circuit.
   Carrying the oxygen and nutrients to various tissues and organs of our body, delivering carbon dioxide to the lungs and accepting oxygen, bringing the metabolic by products to the kidneys, regulating the body's defence mechanism, that is, the immune system and facilitating an effective heat and mass transfer across the body are some of the major functions which blood performs in the human body.
   Section::::Medical breathing gases.
  
  Medical use of breathing gases other than air include oxygen therapy and anesthesia applications. 
  
  Section::::Medical breathing gases.:Oxygen therapy.
  
  Oxygen is required by people for normal cell metabolism. Air is typically 21% oxygen by volume. This is normally sufficient, but in some circumstances the oxygen supply to tissues is compromised. 
   BULLET::::- Fast fatiguing (FF) motor units stimulate larger muscle groups, which apply large amounts of force but fatigue very quickly. They are used for tasks that require large brief bursts on energy, such as jumping or running. They gain their energy via glycolytic means and hence don't require oxygen. They are called white fibers.
   Muscles are predominantly powered by the oxidation of fats and carbohydrates, but anaerobic chemical reactions are also used, particularly by fast twitch fibers. These chemical reactions produce adenosine triphosphate (ATP) molecules that are used to power the movement of the myosin heads.
  
  The term muscle is derived from the Latin "musculus" meaning "little mouse" perhaps because of the shape of certain muscles or because contracting muscles look like mice moving under the skin.
  
  Section::::Structure.
  
  The anatomy of muscles includes gross anatomy, which comprises all the muscles of an organism, and microanatomy, which comprises the structures of a single muscle.
  
  Section::::Structure.:Types.
   During development, myoblasts (muscle progenitor cells) either remain in the somite to form muscles associated with the vertebral column or migrate out into the body to form all other muscles. Myoblast migration is preceded by the formation of connective tissue frameworks, usually formed from the somatic lateral plate mesoderm. Myoblasts follow chemical signals to the appropriate locations, where they fuse into elongate skeletal muscle cells.
  
  Section::::Physiology.
  
  Section::::Physiology.:Contraction.
  