Respiration study notes (in plants and humans), Study notes of Biology

Download Respiration study notes (in plants and humans) and more Study notes Biology in PDF only on Docsity! Biolog yChapter -10 Respiration ~Introduction~ Respiration is the process by which energy is released from food. This usually requires oxygen. The reaction of food and oxygen is called as oxidation. Substances that release energy are called as fuels. Thus, food that we consume is a fuel of our body. The substance that is oxidized during respiration is called glucose. The oxidation reaction is as follows: C6H12O6 +6O2+6H2O+ Energy Glucose + Oxygen  Carbon dioxide + water ~Breathing and Cellular respiration~ External Representation or breathing involves the exchange of 2 gases oxygen and carbon dioxide. Cellular respiration involves the release of energy in cells. Carbon dioxide and water vapor are the waste products of this process. ~External Respiration in Humans~ The main organs of respiration in humans are the lungs.  Air is drawn into the nostrils during breathing and the dust particles, germs get trapped by the mucus of the nostrils. The hair present in the nostrils are used to filter the air. The air also gets warm.  The clean warm air now passes through the pharynx into the trachea or windpipe and then into the lungs by 2 tubes called bronchi.  Each bronchi enters the lungs. Lungs are spongy air sacs. They are protected by the flexible rib cage. At the bottom of  In the lungs the bronchi branch into bronchioles. At the end of the bronchioles is the alveoli that are richly supplied with blood. They are also called as air sacs. They have a dense network of capillaries.  They have very thin walls so that the exchange of air and blood takes place ~Mechanism of breathing~ There are two mechanisms of breathing. Inhalation: The process of taking in air is called inhalation. When in inhalation, the muscles present in between the lungs contract and move the ribs upwards and outwards. The diaphragm also contracts and becomes flat. The breastbone also moves outwards. As a result, the volume of the cavity increases and the pressure decreases. The air then flows into the lungs. Exhalation: The process of breathing out air is called as exhalation. During exhalation, the muscles present in between the ribs come to its original place. The diaphragm also becomes dome shaped. The breastbone returns to its original state. The volume hence decreases causing the pressure to increase which forces the air to go out of the lungs. ~Exchange of gases in the alveoli ~ The process by which a substance flows from an area of lower pressure to an area of high pressure is called diffusion.  The blood carrying oxygen is sent to the heart through the blood vessels. The heart then pumps it to all the parts of the body.  Carbon dioxide is the product of cellular respiration, is carried to the alveoli by the blood. It diffuses from the blood to the air in the alveoli. The carbon dioxide rich air is sent out of the body when the air is exhaled. ~External respiration in other organisms~ Breathing takes place in other living organisms as well. In fact, all of them!  Single celled organisms like amoeba and paramecium exchange gases through their cell membranes through the process of diffusion.  In the hydra the breathing occurs through diffusion on their outer surface of the body.  Earthworms exchange gases through their, moist skin. They have a system of