KA7: Absorption of Materials Flashcards
What happens to oxygen and nutrients?
Absorbed into the bloodstream to be delivered to cells for respiration
What is oxygen used for?
Respiration
What are nutrients used for?
Food for respiration
What happens to waste materials such as carbon dioxide from respiration?
Must be removed from cells into the bloodstream
What do tissues contain?
Capillary networks so that materials can be exchanged between the blood and cells
What do capillaries have?
Large surface area to increase absorption of materials because there is more area for diffusion
Thin walls to allow gases to diffuse easily
Extensive blood supply which increases volume of gases that can be diffused across surfaces
What are lungs?
Gas exchange organs that passed oxygen from the alveoli to the blood and carbon dioxide from the blood to alveoli
What are the features of the lungs?
Trachea (wind pipe)
Bronchi
Bronchioles
Alveoli
Why do lungs have lots of alveoli?
For an increased surface area for diffusion of gases
What happens when we breathe?
Oxygen enters the alveoli and is absorbed through the thin wall into the capillaries
Carbon dioxide leaves the capillaries and is absorbed through the thin wall into the alveoli
Why does carbon dioxide move from capillary to alveoli?
Diffusion of carbon dioxide from a high concentration to a low concentration in alveoli
What do tissues contain?
Capillary networks so that materials can be exchanged between blood and cells
Why does oxygen move from alveoli to capillary?
High oxygen concentration in alveoli to low oxygen concentration in blood
How are alveoli suited to their function?
They are surrounded by a dense network of blood capillaries
Alveolus lining in very thin and close to the walls on the blood capillaries
How thick are the walls of capillaries?
One cell thick
What presents ideal conditions for gas exchange between alveoli, air and blood?
Large surface area
Short distance
Thin walls
Good blood supply
What are the two parts of the digestive system?
Associated organs
Alimentary Canal
What are the features of associated organs?
Salivary glands
Liver
Pancreas
Gall bladder
Appendix
What are the features of the alimentary canal?
Mouth
Oesophagus
Stomach
Small intestine
Large intestine
Rectum
Anus
What are carbohydrates broken down into and using what enzyme?
Broken to glucose using amylase
What are proteins broken down into and using what enzyme?
Broken to amino acids using pepsin
What is fat broken down into and using what enzyme?
Broken to fatty acids and glycerol using lipase
What is the main function of the small intestine?
Absorb end products of digestion through its wall to pass to the circulatory system
How is the small intestine efficient?
Because of its long structure and internal folds
The inner lining of the small intestine is not smooth because…
It has thousands of microscopic projections called villi extending from it
Why is the villus wall one cell thick?
To allow diffusion to occur at a greater rate
What are lacteal?
Tiny lymph vessels which absorb glycerol and fatty acids from the breakdown of fats
What does the rich capillary network do?
Absorb glucose and amino acids from the breakdown on starch and protein
