08 Respiration and Circulation - part 01 - Organs of respiratory Exchange

 

08 Respiration and Circulation - part 01 - Organs of respiratory Exchange


Introduction :
  • All living organisms require energy to carry out various life processes. 
  • The energy that is stored in the body in the form of complex organic compounds (potential energy)
  • This energy is not usable by the organisms unless it is converted into usable form. This conversion is achieved through the process of respiration.
Respiration :
  • Biochemical process of oxidation of organic compounds in an orderly manner for the liberation of chemical energy in the form of ATP.
  • For this, the process of gaseous exchange takes place between the organism and the environment. 
  • The site of gaseous exchange : respiratory surface
Organs of respiratory Exchange :
  • Respiratory exchange is a simple physical process. 
  • For efficient gaseous exchange, the respiratory surface should have the following features :
  1. It should have a large surface area.
  2. It should be thin, highly vascular and permeable to allow exchange of gases.
  3. It should be moist.
Gaseous exchange in plants :

  • The shape and structure of plants facilitate gaseous exchange by diffusion. 
  • A terrestrial flowering plant has many air spaces between the cells of stem, leaf and root. These air spaces are continuous. 
  • Oxygen diffuses into the air space through stomata (the pores on leaves and young stems), carbon dioxide and water vapour diffuse out. 
  • In the aerated soil, the oxygen dissolves in the film of moisture or water around the root tissue and enters it by diffusion.
  • Woody flowering plants (trees and shrubs)have an external impervious bark. Here, gaseous exchange occurs through small pores in the stem surface called lenticles.
Respiration in Animals :

  • The respiratory surfaces differ in various animals.
  • In animals, depending upon the complexity of organization and the surrounding medium, certain parts of the body have become specialized into different types of respiratory organs. 
  • In the higher animals, these respiratory organs are also associated with a transport system.

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