Title BREATHING AND EXCHANGE OF GASES.pdf ✅

56 BREATHING AND EXCHANGE OF GASES SCAN CODE Breathing and Exchange of Gases Chapter 17 Breathing and Exchange of Gases Fig.17.1: Respiratory organs in Humans 1. Introduction to Breathing and Respiration ● Breathing is the most important process for survival of living organisms as we can go days without drinking and weeks without eating but can’t go minutes without breathing. ● Oxygen (O2) is utilized by the organisms to indirectly break down nutrient molecules like glucose and to derive energy for performing various activities. Carbon dioxide (CO2) which is harmful is also released during the above catabolic reactions. ● Breathing is a physical process of exchange of oxygen from the atmosphere with carbon dioxide produced by the cell. Fig.17.2: Exchange of gases during breathing
BREATHING AND EXCHANGE OF GASES 57 SCAN CODE Breathing and Exchange of Gases Table Showing the Differences Between Breathing and Respiration Breathing Respiration It is intake of fresh air and removal of foul air It is oxidation of food to form energy It is a physical process It is a biochemical process No energy is released during breathing Energy is release in form of ATP 2. Respiratory organs in Animals ● The anatomy and physiology of the respiratory system varies greatly depending upon the size of organism and atmosphere in which it lives. ● Different organisms have devised different means of obtaining oxygen from the surrounding atmosphere. ● Lower invertebrates like sponges, coelenterates, ctenophores, flatworms and roundworms, etc., exchange O2 with CO2 by simple diffusion over their entire body wall/surface. . Fig.17.3: Gas exchange in Sponge, Hydra and Planaria ● Earthworms use their moist cuticle to transport atmospheric air within the body. ● Insects have a network of tubes (tracheal tubes) to transport atmospheric air within the body. Book lungs are respiratory organs in the terrestrial form of arthropods.
58 BREATHING AND EXCHANGE OF GASES SCAN CODE Breathing and Exchange of Gases Fig.17.4: Respiration via tracheal tubes and book gills in arthropods ● Gills (branchial respiration) or book gills are respiratory organs in the aquatic form of Arthropoda. ● Many molluscs use gills for respiration. Dermal branchiae or papulae and tube feet help in respiration in echinoderms. ● In hemichordates, respiration takes place from gill slits. Fig.17.5: Respiration by gills in Pila Fig.17.6: Respiration via papulae in Asteria ● Gills are evaginated respiratory surfaces in fishes used for breathing in water. Fig.17.7: Respiration from gills in fish