2.3 Human Digestive System

Pn. Rohaillah binti Mohd JabidSMJK Chong Hwa,KL

1. We actually eat mixture of carbohydrates, proteins and fat.

2. All this must be broken into small molecule.3. This will involve the process of digestion.

Digestion

1. Is the process of breaking down large molecule of food into small molecule.

2. This is important, so that the small molecule can be absorbed into the body through the bloodstream.

3. Digestion involve :a) Alimentary canal or gut (tube from mouth to anus)b) Liverc) Pancreas

Secrete the enzymeto break down the food

that we eat

Liver

Pancreas

4. Digestion involve 2 process:a) Physical digestion ( No chemical-using teeth)b) Chemical digestion ( Use chemical- enzyme)

5. Three main enzyme in the human digestive system process:

a) Amylase ( Starch -> Glucose)b) Protease ( Protein -> Amino acid)c) Lipase ( Fat -> Fatty Acid + Glycerol)

AmylaseBreaks down

carbohydrates molecule(eg: Starch to glucose)

Proteases

Breaks down protein molecules

LipasesBreaks down fat molecules

Human Digestive System

1. Food chew into smaller pieces via physical digestion.2. Salivary amylase from the salivary gland will breakdown Starch into Maltose( Kind of sugar)

1. Mouth

2. Oesophagus

1. No enzyme takes place here.

2. The food will become bolus3. The food move from mouth

to stomach via wave-like movement ( Peristalsis).

1. In stomach, gastric juice will release.2. Gastric juice contain Protease and Hydrochloric

acid.3. Protease enzyme will breakdown protein into

polypeptides or peptones4. Hydrochloric acid will:

a) Stop the amylaseb) Give acidic medium for protease actionc) Kill bacteria

3. Stomach

1. Duodenum is the first part of small intestine.

2. Bile- greenish fluid produce by liver and stored in gall bladder.

3. Function of bile is to emulsifies fats into oil droplets for lipase action.

4. Duodenum

1. Pancreas will produce Pancreatic juice that contain amylase, protease and lipase enzyme.

2. Pancreatic amylase breakdown starch to maltose

5. Pancreas

3. Protease breakdown proteins to polypeptides4. Lipase breakdown fat into fatty acids and glycerol

1. Small intestine will secrete Intestinal juice that contain maltase, protease and lipase.

2. Maltase will breakdown maltose into glucose.

6. Small intestine

3. Protease breakdown polypeptides into amino acid.4. Lipase breakdown fats into fatty acids and glycerol.

Conclusion for amylase..

•Starch

Amylase (Mouth & Duodenum)

•Maltose

Maltase (Small Intestine) •Glucose

End Product

Conclusion for protease..

• Protein

Protease (Stomach & Duodenum)

• Polypeptides

Protease (Small intestine) • Amino Acid

End Product

Conclusion for lipase..

•Fat

Lipase (Duodenum &

Small Intestine)

•Fatty acid + Glycerols

End Product

End products of digestion are:

-Glucose from carbohydrates-Amino acids from proteins-Fatty Acids and glycerol from fat