Explain what happens to digested food enters the blood stream? lOng answer
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Answer:
The small intestine absorbs most digested food molecules, as well as water and minerals, and passes them on to other parts of the body for storage or further chemical change. Specialized cells help absorbed materials cross the intestinal lining into the bloodstream. The bloodstream carries simple sugars, amino acids, glycerol, and some vitamins and salts to the liver. The lymphatic system, a network of vessels that carry white blood cells and a fluid called lymph throughout the body, absorbs fatty acids and vitamins.
Answer:
Absorption and egestion
These are the processes that happen in the digestive system:
ingestion (eating) → digestion (breaking down) → absorption → egestion (removal from the body)
Absorption
Digested food molecules are absorbed in the small intestine. This means that they pass through the wall of the small intestine and into our bloodstream. Once there, the digested food molecules are carried around the body to where they are needed.
Only small, soluble substances can pass across the wall of the small intestine. Large insoluble substances cannot pass through. The slideshow shows how this happens:
Food in the small intestine, and the wall of the small intestine which divides it from the blood stream
Food molecules in the small intestine are too large to pass across its wall and into the bloodstream
Adaptations for absorption
Absorption across a surface happens quickly and efficiently if:
the surface is thin
its area is large
The inner wall of the small intestine has adaptation so that substances pass across it quickly and efficiently:
it has a thin wall, just one cell thick
it has many tiny villi to give a really big surface area
If the small intestine had a thick wall and a small surface area, a lot of digested food might pass out of the body before it had a chance to be absorbed.
The villi (one of them is called a villus) stick out and give a big surface area. They also contain blood capillaries to carry away the absorbed food molecules.
Shows that the walls of the villi are just one cell thick, and the network of capillaries, and the blood vesselsThe structure of villi
Egestion
Excess water is absorbed back into the body in the large intestine. What is left then is undigested food. This is stored in the rectum, the lower part of the large intestine, until we are ready to go to the toilet. It then comes out of the rectum through the anus as faeces. This process is called egestion. Take care not to confuse egestion with excretion.
The digestive system contains many bacteria and about half of the dry weight of faeces consists of bacteria. Bacteria in the digestive system are important. For example, they:
can digest some substances that humans cannot digest, such as certain carbohydrates
reduce the chance of harmful bacteria multiplying and causing disease
produce some vitamins that humans need, such as vitamins B and K
The process of how we digest our food from start to finish
Explanation:
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