Digestion

What is digestion?

This is the physical and chemical breakdown of food for use by the body.

What are the parts of the digestive system?

The alimentary canal and the accessory organs.

What are the 2 types of digestion?

Chemical and mechanical

What is mechanical digestion and where does it occur?

This is the physical breakdown of food. It occurs in the:

1. Mouth- teeth, tongue and palates

2. Esophagus- during peristalsis

3. Stomach- muscular churning action of the stomach

4. Small intestine- bile and peristalsis

What is chemical digestion?

This is the breakdown of large food molecules into smaller molecules by the action of enzymes.

What are enzymes?

This is a protein that acts as a biological catalyst by accelerating chemical reactions.

What are the important characteristics of enzymes?

1. They remain unchanged at the end of a chemical reaction

2. They do not change the products after the reaction

3. They are highly selective, catalyzing specific reactions

4. They speed up the same chemical reaction going in opposite directions

5. Nearly all known enzymes are proteins

What is the enzyme in the mouth and what is its function?

The salivary amylase. It breaks down starches into disaccharides

What is the enzyme in the stomach and what is its function?

Pepsin. It breaks down proteins into large peptides.

What are the enzymes in the mouth and what are their function?

1. Amylase- to continue the breakdown of starch

2. Trypsin- to continue the breakdown of protein

3. Lipase- to breakdown fat

What are the enzymes in the small intestines and what are their functions?

1. Maltase, sucrose, and lactase- to breakdown remaining disaccharides into monosaccarides.

2. Peptidase- to breakdown dipeptidase into amino acids.

What is the mouth?

This is the opening and cavity in the lower part of the human face, surrounded by the lips, through which food is taken in and vocal sounds are emitted.

What is the tongue?

This is the fleshy muscular organ in the mouth of a mammal used for tasting, licking, swallowing, and in humans, articulating speech.

What is the oesophagus?

This is a muscular tube lined with mucous membrane that connects the throat to the stomach. It is part of the alimentary canal.

What is the stomach?

This is a pear-shaped internal organ in which the major part of digestion occurs. It links the oesophagus to the small intestine.

What is the liver?

This is a large lobed glandular organ in the abdomen of vertebrates and is involved in many metabolic processes.

What is the gall bladder?

This is a small sac-shaped organ beneath the liver, in which bile is stored after secretion by the liver and before release into the intestine.

What is the pancreas?

This is a large gland behind the stomach which secretes digestive enzymes into the duodenum.

What is the small intestine?

This is a tube-like structure that forms part of the digestive system. It is the site where most food is absorbed. It connects the stomach and the large intestine and helps to further digest food coming from the stomach. It absorbs water and nutrients from food so they can be used by the body.

What is the large intestine?

This is a long, tube like organ that is connected to the small intestine at one end and the anus at the other. In the large intestine, partly digested food moves through the caecum into the colon, where water and some nutrients and electrolytes are removed.

What is the rectum?

This is a chamber that begins at the end of the large intestine, immediately following the sigmoid colon, and ends at the anus.

What is the anus?

This is the opening at the far end of the digestive tract through which stool leaves the body.