Human Respiratory system
11. Human Body - Respiratory system
Respiratory system
The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases is the respiratory systems means of getting oxygen to the blood. Respiration is achieved through the mouth, nose, trachea, lungs, and diaphragm. Oxygen enters the respiratory system through the mouth and the nose. The oxygen then passes through the larynx (where speech sounds are produced) and the trachea which is a tube that enters the chest cavity. In the chest cavity, the trachea splits into two smaller tubes called the bronchi. Each bronchus then divides again forming the bronchial tubes. The bronchial tubes lead directly
into the lungs where they divide into many smaller tubes which connect to tiny sacs called alveoli. The average adults lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. The inhaled oxygen passes into the alveoli and then diffuses through the capillaries into the arterial blood. Meanwhile, the waste rich blood from the veins releases its carbon dioxide into the alveoli. The carbon dioxide follows the same path out of the lungs when you exhale.
into the lungs where they divide into many smaller tubes which connect to tiny sacs called alveoli. The average adults lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. The inhaled oxygen passes into the alveoli and then diffuses through the capillaries into the arterial blood. Meanwhile, the waste rich blood from the veins releases its carbon dioxide into the alveoli. The carbon dioxide follows the same path out of the lungs when you exhale.
- The total lung capacity of an adult is 5.0 litres
- Tidal air : Volume of air entering and leaving the lungs during normal breathing (.5 litres)
- Vital capacity : Volume of air exhaled after a forceful breathing (3.5 litres)
- Residual air : Volume of air which remains after forceful expiration (1.5 litres)
The diaphragms job is to help pump the carbon dioxide out of the lungs and pull the oxygen into the lungs. The diaphragm is a sheet of muscles that lies across the bottom of the chest cavity. As the diaphragm contracts and relaxes, breathing takes place. When the diaphragm contracts, oxygen is pulled into the lungs. When the diaphragm relaxes, carbon dioxide is pumped out of the lungs.
Cellular respiration
Cellular respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water. The energy released is trapped in the form of ATP (adenosine triphosphate) for use by all the energy-consuming activities of the cell.
The process occurs in two phases:
1) glycolysis, the breakdown of glucose to pyruvic acid
2) the complete oxidation of pyruvic acid to carbon dioxide and water. This process called aerobic respiration. When the respiration takes place with out oxygen it is known as anaerobic respiration. The end product of anaerobic respiration is carbon dioxide and chemical such as lactic acid and ethanol. When the micro organisms respire anaerobically we call it as fermentation. e.g. fermentation of yeast in the preparation of ethanol.
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