Biology chapter 7: Human Nutrition

Lack of Vitamin C:

Scurvy
Symptoms:

• tooth loss

• swelling

• anemia

  Prevent by:

• Eating citrus fruits

Lack of Vitamin D:

Rickets

• (Poor bone development)

• Vitamin D is crucial for the absorption of calcium

  Ways to prevent:

• Eating food contains calcium, vitamin D like fish, egg, butter

Calcium, D:

• Vitamind D helps the body to absorp calcium, required for strong bones, teeth

• Strong teeth, bones, involved in the clotting of blood

• Milk, Cheese, eggs

Iron:

To make haemoglobin, the pigment in RBC

• Liver, red meat, pork

The pathway of food in Human’s body

• Mouth

• Oesophagus

• Stomach

• Small intestine:

• Duodenum

• Ileum

• Large intestine:

• Colon

• Rectum

• Anus

The digestive system

Types of teeth + roles

• hey

Stomach

• Produced Pepsin, breaking down protein in acidic condition

• The lining contains muscles

• Physically squeeze and mix it with HCl

• Digest the food for several hours

Substance produced by Liver + Their roles:

• Produced Bile, secreted it into the duodenum

• Bile roles:

• Neutralise HCl from the stomach, Which helps to create an optimum pH conditions for Enzymes in the Small Intestine to work

• Emulsify lipids, for lipase to digest it easier

Gall bladder

• Where bile is stored

Pancreas

• PANCREAS ONLY PRODUCE ENZYMES. The enzyme will be secreted into the duodenum.

• Produced Amylase, breaking down Starch into Maltose.

  After this, Maltose will be broken down into Glucose by Maltase in the small intestine

• Produced Trypsin, help to break down proteins

• Produce Lipase, help to break down lipids

Absorption (Nutrients + water)

• Movement of digestive food molecules into the blood (glucose and amino acids) and lymph (fatty acids and glycerol)

• Nutrients are absorbed in the small intestine

• Water: small intestine + colon

Adaptations of the small intestine

• Long, highly folded surface, containing millions of villi => Increase SA, allowing absorption to occur faster + more efficiently

• Presence of villi

• Villus:

• Has epithelium cells on outer surface, the EC contains microvilli on the outside. SA higher

• Epithelium cell is one cell thick => More efficient diffusion of nutrients

• Lacteals: absorption of FA + G

• Capillaries: good blood supply