| what must happen to oxygen and nutrients + waste materials in the bloodstream | oxygen and nutrients from food must be absorbed into the bloodstream and delivered to cells for respiration
waste materials like carbon dioxide must be removed from cells into the bloodstream
tissues contain capillary networks allow the exchange of materials at cellular levels |
| what features must surfaces involved in the absorption of materials have? | large surface area
thin walls
extensive blood supply
these features increase the efficiency of absorption |
| describe the structure of the lungs as body organs of gas exchange | when we breathe in, air moves down the trachea (wind pipe).
This then branches off into the right and left bronchus which branch into further narrower tubes called the bronchioles.
The windpipe and bronchus are supported and held open by rings of cartilage.
At the end of the bronchioles are the the alveoli (air sacs) and this is where gases are exchanged with the blood |
| how does the structure of alveoli help with gas exchange | the lungs consist of a large number of alveoli which provide a large surface area oxygen and carbon dioxide are absorbed through the thin alveolar walls to or from the many blood capillaries |
| describe what the diffusion happening between an alveolus and a blood capillary | blood which arrives in the lungs is deoxygenated. The air breathed into the alveoli in the lungs has a high oxygen concentration. The oxygen diffuses from a high oxygen concentration in the lung alveoli to a low oxygen concentration in the blood and its red blood cells. The blood then becomes oxygenated and is pumped to respiring cells.
Deoxygenated blood arriving at the lung alveoli will have a higher concentration of carbon dioxide than the air in the lungs. This means that carbon dioxide will diffuse from a high carbon dioxide concentration to a low carbon dioxide concentration in the alveoli in the lungs and will then be breathed out out the lungs. |
| what is the substrate and product of the enzyme amylase? | amylase breaks down the substrate starch (a carbohydrate) into glucose |
| what is the substrate and product of the enzyme protease? | protease breaks up the substrate protein into amino acids |
| what is the substrate and product of the enzyme lipase? | Lipase breaks up the substrate fat into fatty acids and glycerol |
| where are nutrients of food absorbed into? | the villi in the small intestine |
| how does the villi's structure make it appropriate for the absorption of materials? | there is a large number of thin walled villi which provides a large surface area.
Each villi contains a network of capillaries to absorb glucose and amino acids, and a lacteal to absorb fatty acids and glycerol |
| name each part of this villus | A - Thin Surface Layer
B - Blood Capillary
C - Lacteal |
| What is the lacteal responsible for absorbing | glycerol and fatty acids |
| What are the blood capillaries in the villi responsible for absorbing | glucose and amino acids |
| Describe what happens in our digestive systems when we eat food | When we eat food many of the food molecules are insoluble in their original form and must be digested in order to be absorbed
Enzymes in the digestive system break down large insoluble molecules in to smaller more soluble products so that they can diffuse for absorption.
The now soluble nutrients from food are absorbed into the villi in the small intestine. The large number of thin walled villi lining the small intestine provides a large surface area for absorption
There is a capillary network in each villus to absorb glucose and amino acids
There is also a lacteal in each villus to absorb glycerol and fatty acids
After these small food molecules are absorbed, they will then be transported in the blood stream and diffuse into body cells |
| What can the small food molecules that diffuse into our body cells during diffusion be used for? | Glucose can be used by body cells during the process of aerobic respiration in order to make energy
The liver will build up any extra glucose into the compound glycogen to be stored until it is needed.
The amino acids will be used by the body to make proteins.
The fatty acids and glycerol area transported to and diffuse into cells and are used as energy sources and any extra is stored under the skin or around organs as fatty tissue. |
