Respiration in humans grade 7 notes

respiration, breathing, cellular respiration, aerobic and anaerobic respiration, organs of breathing, lungs, inhalation , exhalation.

1. Respiration in H umans 1 LIKE AND SUBSCRIBE MEERA CHAVDA

2. → The process of taking oxygen into the body and then oxidation of food with this oxygen and release of carbon dioxide and energy is called respiration . → Process of respiration :- 2 LIKE AND SUBSCRIBE MEERA CHAVDA

3. Anaerobic respiration Fermentation by Yeast:- Anaerobic breakdown of sugars into alcohol is called fermentation. Yeast is single cell organism. It respires anaerobically and gives ethyl alcohol. That is why yeast is used for making alcohol, vine, beer. Yeast is used in baking industry. Lactic acid formation in muscles:- During vigorous muscular activity, demand of oxygen is increased but the supply of oxygen is limited. So, glucose of the muscles cells breaks down into lactic acid in less supply of oxygen. Lactic acid produced in the muscles gets accumulated and give rise to muscles cramp. During massage with oil, blood supply in muscles increases and stored lactic acid is now broken down into carbon dioxide and water. 3 LIKE AND SUBSCRIBE MEERA CHAVDA

4. Breathing and cellular respiration B reathing Cellular respiration Mechanical process Takes place in lungs External respiration Its process of pumping air into and out of the lungs Chemical process Takes place in each and every cell of our body. Release of energy 4 LIKE AND SUBSCRIBE MEERA CHAVDA

5. Aerobic and anaerobic respiration Aerobic Respiration Anaerobic Respiration or (fermentation) Breakdown of glucose occurs in presence of oxygen. Organisms that use oxygen for respiration are called aerobes. Glucose is completely oxidised. More energy is produced(38 ATP from one mole of glucose). End products are carbon dioxide and water. Example :- Most plants and animals. Glucose is broken down in absence of oxygen. Organisms that can survive and produce energy in absence of oxygen are called anaerobes. Incomplete oxidation of glucose takes place. Very little energy is produced ( 2 ATP from one mole of glucose). End products are ethyl alcohol and carbon dioxide or lactic acid. Example:- yeast, anaerobic bacteria and parasitic worms. 5 LIKE AND SUBSCRIBE MEERA CHAVDA

6. Organs of breathing Nose, nasal passage and wind pipe:- We breath air through nose or nostrils. In nasal passage the air gets filtered, warmed, and moistened before entering lungs. That is why we should breath with nose and not with mouth. From nasal passage air goes to the wind pipe . Wind pipe is divided into two bronchi which enters into each lung . Inside the lungs the bronchi re-divide into smaller and smaller pipes and finally end into air sacs or alveoli. 6 LIKE AND SUBSCRIBE MEERA CHAVDA

7. 7 LIKE AND SUBSCRIBE MEERA CHAVDA

8. Lungs:- (Main respiratory organ) Lungs are a pair of spongy, highly elastic and bag like structure . They enclosed thin walled and tiny air sacs called Alveoli. The surface of alveoli is covered with a network of blood capillaries. Functions of alveoli :- 1. When we breath in, these alveoli are filled with oxygenated air. The oxygen from air enters the blood capillaries and the carbon dioxide from blood comes out . 2. Alveoli has large surface area for the exchange of oxygen and carbon dioxide between the air in the alveoli and blood in the alveolar capillaries. 8 LIKE AND SUBSCRIBE MEERA CHAVDA

9. Breathing and breathing rate:- Breathing:- Breathing is a mechanical process which involves taking in of oxygen rich air into the lungs and giving out carbon dioxide from the lungs. Inhalation:- Taking in of air rich in oxygen into the lungs is called inhalation. Exhalation:- Giving out the air rich in carbon dioxide is known as exhalation. One breath:- One breath mean one inhalation and one exhalation. Breathing rate:- The number of times a person breathes in a minute is termed as breathing rate. 9 LIKE AND SUBSCRIBE MEERA CHAVDA

10. Mechanism of breathing:- 10 LIKE AND SUBSCRIBE MEERA CHAVDA

11. Inhalation and exhalation:- Inhalation Exhalation Ribs move upwards and outwards Diaphragm moves down. Due to this the volume of thoracic cavity increases. Lungs increase in size and air pressure in the lungs decreases. Atmosphere have higher air pressure so, air from atmosphere rush into the lungs and lungs get filled with fresh air. Ribs move downward and inward. Diaphragm moves up. Due to this volume of thoracic cavity decreases. Size of the lungs decrease and air pressure inside lungs increases. Increased air pressure inside the lungs push the carbon dioxide rich air out in atmosphere. 11 LIKE AND SUBSCRIBE MEERA CHAVDA

12. Like and subscribe LIKE AND SUBSCRIBE MEERA CHAVDA 12