absorbtion of materials

• oxygen from the air nutrients from food must be absorbed into the bloodstream to he delivered to the crlls for respiration
• during respiration, waste materials such as carbon dioxide must be removed from cells into the blood stream
• the features that surfaces need to make absorption more efficient such as a large surface area , thin walls and extensive blood supply
• at the end of our lungs we have airsacks called alveoli it is here where the lungs exchange gases
• there is a large number of alveoli in the lungs. the alveoli are highly efficient for the absorption of gases
• alveoli has a large surface area to absorb oxygen
• alveoli has a moist surface which allows gases to dissolve in water for diffusion
• alveoli has a thin lining to allow oxygen to diffuse in or out of the blood easily
• alveoli has a thin lining to allow oxygen to diffuse in or out of the blood easily
• alveoli has a extensive network of blood capillaries surrounding the alveoli to pick up and transport oxygen
• when you breathe in the air that reaches the alveoli oxygen is absorbed through the thin alveolar walls via diffusion into one of the many blood capillaries
• the oxgenated blood is then taken to the heart to be transported to the respiring cells around the body
• deoxygenated blood returns to the lungs with increased levels of carbon dioxide this waste gas is absorbed through the thin alveolar walls and is exhaled
• nutrients from food are absorbed into the villi in the small intestine
• in the small intestine there is a large number of thin walled villi this provides a large surface area
• like the alveoli in the lungs villi are also surrounded by a network of capillaries
• the capillaries of each villi absorb glucose and amino acids
• glucose is used as a energy for respiration
• excess glucose is converted into glycogen and stored in the liver/muscles
• amino acids are used in protein synthesis for growth, maintenance and tissue repair
• each villi has a lacteal. this vessel allows fatty acids and glycerol to be absorbed
• excess fatty acids are glycerol are converted to fat and stored in the bodys fatty tissues until required