Page 54 - Biology Form Two

Biology for Secondary Schools

Table 2.2: The end products of digestion of food substances
Complex food substances Simple, soluble, absorbable end
products
Carbohydrates such as starch and Simple sugars, such as glucose,
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sucrose fructose, and galactose
Proteins such as beef, milk, Amino acids
chicken, and fish
Fats and oils such as butter, cheese, Fatty acids and glycerol
cooking oil, groundnuts, and
coconuts
Vitamins sources such as fruits, Vitamins A, B, C, D, E, and K
milk, and vegetables
Mineral sources such as vegetables, Mineral elements like potassium,
liver, fish, iodized salt, and water sodium, iron, magnesium, iodine,
calcium, chloride, fluoride, and nitrate

The absorption of digested food the blood stream. After the absorption
takes place in the small intestine. The of the final products of digestion into
end products of digestion including the blood stream, the body uses them
glucose, galactose, fructose, amino for various functions such as growth,

acids, vitamins, and minerals are body repair, respiration, excretion, and
absorbed into the blood stream through reproduction. This process is called
blood capillaries of the villi. These assimilation.

products of digestion are transported The adaptation of ileum for digestion
to the liver through the hepatic portal and absorption of food
vein.
(i) The ileum has secretory glands that
The villi also have lymphatic vessels secrete digestive enzymes. These

called lacteals. The lacteals absorb enzymes finalise the digestion of
fatty acids and glycerol that are the end food substances.
products of digestion of fats and oils.
Thus, fatty acids and glycerol enter (ii) It contains mucus that ensures
into the blood stream through lacteals. constant lubrication of the internal

The lacteals help to increase the walls for effective digestion of
absorption rate of digested foods into foods.

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