Digestive System

Question 1

What does the digestive system breakdown?

Answer 1

Macromolecules: proteins, carbohydrates, nucleic acids, and lipids into smaller subunits so that it can be absorbed and used for energy production, growth maintenance and repair

Question 2

Alimentary canal

Answer 2

a tube that runs from the mouth to the anus consisting of hollow organs including the mouth, oesophagus, stomach, small & large intestines, and anus.

Question 3

Accessory organs

Answer 3

solid organs release secretions such as enzymes into the alimentary canal

Question 4

Mechanical digestion

Answer 4

Breaks down food into smaller parts using physical movements of the body.

teeth grind food
stomach mixes and churns food
intestines squeeze and move food

Question 5

Chemical digestion

Answer 5

Breakdown of foods using chemical processes and occurs in the mouth, stomach and small intestine.

Large food molecules can be broken down by enzymes and chemicals such as acids. Large molecules called polymers are broken down into single molecules called monomers

Question 6

Mouth

Answer 6

food is broken down by the teeth as mechanical breakdown. It increases the SA of food. The ball of food that leave the mouth is called bolus.

Salivary glands secrete a watery saliva that contains the carbohydrate digesting enzyme, amylase

Lingual glands on the surface of the tongue secrete the fat-digesting lipase

Question 7

Esophagus

Answer 7

The epiglottis a small flap of cartilage blocks the entrance to the larynx which stops the food from going down the wrong way and preventing choking.

Peristalsis: series of muscle contractions and relaxation that moves food towards the stomach

Question 8

Stomach

Answer 8

Temporary holding chamber for ingested food.
Churning of content
Digested food: Chyme
Enzymatic digestion
Gastric juice secreted by epithelial cells in gastric glands

Gastric glands cells:
Parietal cell: secretes hydrochloric acid (PH2-3)
Chief cells: secrete enzyme gastric lipase and pepsinogen

Question 9

Small intestine

Answer 9

Digestion: Pancreatic juice and Bile (important in breakdown of fats)

Absorption:
Duodenum: site of absorption for fatty acids and water-soluble vitamins
Jejunum: Absorbs glucose and amino acids
Ileum: absorbs bile salts and vitamin B12