Digestive system

Question 1

Functions of the digestive system

Answer 1

1. ingestion
2. Secretion
3. peristalsis
4. Digestion
5. Absorption
6. Defecation

Question 2

What is ingestion in the digestive system?

Answer 2

Ingestion involves taking foods and liquids into the mouth (eating). It occurs when materials enter the digestive tract via the mouth.

Question 3

What is secretion in the digestive system?

Answer 3

Secretion involves the cells of the walls of the gastrointestinal tract and accessory digestive organs secreting about 7 liters of water, acid, buffers, and enzymes into the lumen of the tract.

Question 3

What is peristalsis in the digestive system?

Answer 3

Peristalsis is the rhythmic, wavelike intestinal contractions that move and mix food through the gastrointestinal tract.

Question 3

What is digestion in the digestive system?

Answer 3

Digestion is the breakdown of ingested food into small molecules for use by body cells.

It includes mechanical digestion (cutting and grinding of food by teeth and mixing by stomach and small intestine muscles) and chemical digestion (breakdown of large molecules by digestive enzymes).

Question 4

What is defecation in the digestive system?

Answer 4

Defecation is the discharge of indigestible wastes, called feces, from the gastrointestinal tract.

Question 4

What is absorption in the digestive system?

Answer 4

Absorption is the entrance of ingested and secreted fluids, ions, and the products of digestion into the epithelial cells lining the lumen of the gastrointestinal tract.

These substances then pass into the blood or lymph and circulate to cells throughout the body.

Question 5

What are the main parts of the digestive system?

Answer 5

The digestive system is divided into the tubular gastrointestinal (GI) tract or alimentary canal, and accessory digestive organs.

Question 6

What is the gastrointestinal (GI) tract?

Answer 6

The GI tract is a continuous tube that extends from the mouth to the anus through the thoracic and abdominopelvic cavities, about 5–7 meters long in a living person and 7–9 meters in a cadaver.

Question 7

What are the four layers of tissue in the walls of the GI tract?

Answer 7

• Adventitia or serosa (outer covering)
• Muscle layer
• Submucosa
• Mucosa (lining)

Question 8

What is the gall bladder and where is it located?

Answer 8

The gall bladder is a pear-shaped sac located on the under surface of the liver, attached by connective tissue.

Question 9

How is the gall bladder divided for descriptive purposes?

Answer 9

• The fundus (outer expanded end)
• The body (directed upwards, backwards, and to the left on the under surface of the liver),
• The neck (narrow, passing upwards and forwards, then curving sharply downwards to become continuous with the cystic duct).

Question 10

What are the functions of the gall bladder?

Answer 10

• Serving as a reservoir for bile
• Concentrating bile by up to 10- or 15-fold through absorption of water

*Releasing stored bile