Science (Digestive system)

Question 1

1. What are the four stages of digestion?

2. What is digestion?

Answer 1

1. Ingestion, digestion, absorption, elimination

2. Process of breaking food down into molecules small enough to absorb

Question 2

What type of digestion occurs in the mouth when food is mixed or crushed with your teeth?

Answer 2

Mechanical digestion

Question 3

What is the chemical digestion that occurs in the mouth?

Answer 3

Digestive enzymes break down complex polymers into monomers

Question 4

What is an enzyme?

Answer 4

Molecule that allows a substances to be converted into smaller molecules

Question 5

1. What is amylase?

2. What does it do?

Answer 5

1. An enzyme produced by the salivary glands and found in saliva
2. Breaks down starch into maltose

Question 6

What does the tongue do to the food in the mouth?

Answer 6

Forms it into a bolus

Question 7

1. When is the swallowing reflex stimulated?
2. What is the pharynx?
3. What is an epiglottis?

Answer 7

1. When food enters the pharynx
2. Place in throat that opens up into trachea and esophagus
3. A flap that flops down over the windpipe and allows food to enter esophagus

Question 8

1. How long is the esophagus and what does it connect to?
2. What is the sphincter valve?
3. What is peristalsis?

Answer 8

1. 25cm, connects to stomach
2. Food enters it but is prevented from going back up
3. When food is pushed down the esophagus with help of involuntary muscle contractions

Question 9

What are the stomach’s 3 functions?

Answer 9

1. To store up to 2L of food and fluid
2. To break down the food into liquid mixture
3. To slowly empty liquid mixture into small intestine

Question 10

1. What is churning?

2. What is gastric juice made up of?

Answer 10

1. When the smooth muscle in the stomach mixes the food

2. Hydrochloric acid, mucous, enzyme pepsin

Question 11

1. What does the hydrochloric acid in the gastric juice do?
2. What is the role of pepsin?
3. What does mucous do?

Answer 11

1. Breaks down meat and plant material, kills bacteria in food
2. Breaks down proteins into smaller amino acid chains
3. Protects the lining of the stomach from the acid

Question 12

1. What does the bolus become?

2. This liquid is released from the stomach via what?

Answer 12

1. Acid chyme

2. Pyloric sphincter

Question 13

If the inner linings of the stomach are exposed to acid, what does this cause?

Answer 13

1. Irritation (gastritis)

2. Ulcers (sore/hole in stomach)

Question 14

1. Approx. how long is the small intestine?
2. What is its main function?
3. What are the names of the 3 parts of this organ?

Answer 14

1. 6-7m long
2. Transport nutrients into your bloodstream
3. Duodenum, jejenum, ileum

Question 15

1. What are villi?

2. What does each villi contain?

Answer 15

1. Folds on the small intestine that look like fingers and are made up of epithelial cells
2. Microvilli

Question 16

Why do villi and microvilli increase the surface area of the small intestine?

Answer 16

1. Allows more nutrients to be absorbed into the bloodstream

2. Nutrients are absorbed into the blood faster

Question 17

In the duodenum, the acid chyme mixes with digestive juices from which 3 other organs?

Answer 17

Pancreas, liver, gallbladder

Question 18

1. What enzymes does the pancreas produce and why?

2. What else does it produce and why?

Answer 18

1. Lipase, to break down fats

2. Basic solution to neutralize the acid from chyme

Question 19

1. What does the liver produce?
2. What is it?
3. Where is it stored?

Answer 19

1. Bile
2. A liquid that allows fats to be absorbed into the bloodstream
3. Gallbladder

Question 20

What are the liver’s functions?

Answer 20

1. To filter out harmful substances and turn some into more bile
2. Determines the amount of nutrients that will be distributed to the body

Question 21

1. Small intestine empties into the ______ of the large intestine.
2. Waste products will be stored in the ___.

Answer 21

1. Cecum

2. Rectum

Question 22

What is a physical change?

Give an example.

Answer 22

Physical changes: when the molecules that you started with are in the same form but just in a different place
Example: cutting a piece of paper or ice melting into water

Question 23

What is a chemical change?

Give an example.

Answer 23

Chemical changes: the molecules you have started with are no longer in the same form
Example: mixing saliva with food or lighting a match

Question 24

What are the signs that a chemical change has occurred?

Answer 24

1. Gas or precipitate (something solidifies out of solution or reaction) forms
2. Colour change
3. Production of heat or light
4. A reaction that is often very difficult/impossible to reverse without another chemical change