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Exchange of gases in human lungs and tissues

The atmospheric air contains

  • Oxygen – 20.9 %

  • Carbon dioxide – 0.04 %

  • Nitrogen and other inert gases – 79 %

  • Water Vapors – variable

The air reaches to the alveoli of the lungs. Exchange of gases in the lungs occurs between the blood of the blood capillaries and the air of the alveoli of the lungs.

The basic properties involved in gas exchange are

  • Gases always diffuse from the area of high concentration to the area of low concentration.

  • Gases always fill their container completely.

  • Gases exert pressure upon all the walls of the container.

  • Molecules of the gases… (523 more words) …

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Regulation of Respiration (control of respiration)

Regulation of ventilation

The main aim of regulation/control is to maintain level of oxygen and carbon dioxide within normal limits, during rest as well during various activities. Spontaneous respiration is controlled by

  1. Nervous regulation

  2. Chemical regulation

The Nervous regulation the neurons for this type of regulation are present in

  • Medulla; there are two groups of neurons to form

  • Inspiratory centre or dorsal medullary centre (DRG). It is present in dorsomedial region of medulla. It has autorhythmicity and can generate its own impulses even if all the external signals are cut off. Stimulation of this centre causes inspiration. Impulses are generated… (610 more words) …

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