The small intestine is lined with many villi and is adapted to absorb glucose. Fig. 2.1 shows two villi from the lining of the small intestine. Describe and explain how the structure of a villus is adapted for its function.

Biology

IGCSE&ALevel

CAIE

Exam No：0610_w23_qp_41 Year：2023 Question No：2(a)(iv)

Answer:

Knowledge points:

7.2.1 Define ingestion as the taking of substances, e.g.

7.2.10 Describe cholera as a disease caused by a bacterium

7.2.11 Identify the main regions of the alimentary canal and associated organs, limited to mouth, salivary glands, oesophagus, stomach, small intestine (duodenum and ileum), pancreas, liver, gall bladder and large intestine (colon, rectum, anus)

7.2.12 Describe the functions of the regions of the alimentary canal listed above, in relation to ingestion, digestion, absorption, assimilation and egestion of food

7.2.13 Explain that the cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water into the gut, causing diarrhoea, dehydration and loss of salts from blood

7.2.2 food and drink, into the body through the mouth

7.2.3 Define mechanical digestion as the breakdown of food into smaller pieces without chemical change to the food molecules

7.2.4 Define chemical digestion as the breakdown of large, insoluble molecules into small, soluble molecules

7.2.5 Define absorption as the movement of small food molecules and ions through the wall of the intestine into the blood

7.2.6 Define assimilation as the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells

7.2.7 Define egestion as the passing out of food that has not been digested or absorbed, as faeces, through the anus

7.2.8 Describe diarrhoea as the loss of watery faeces

7.2.9 Outline the treatment of diarrhoea using oral rehydration therapy

7.5.1 Identify the small intestine as the region for the absorption of digested food

7.5.2 State that water is absorbed in both the small intestine and the colon, but that most absorption of water happens in the small intestine

7.5.3 Explain the significance of villi and microvilli in increasing the internal surface area of the small intestine

The small intestine is lined with many villi and is adapted to absorb glucose. Fig. 2.1 shows two villi from the lining of the small intestine. Describe and explain how the structure of a villus is adapted for its function.

Answer:

Knowledge points:

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