Digestion

Question 1

List the parts of the gastrointestinal (digestive) tract in order from the mouth to the colon.

Answer 1

mouth -> esophagus -> stomach -> small intestine -> large intestine (colon)

Question 2

List the organs that assist digestion, but are not part of the digestive tract.

Answer 2

salivary glands, pancreas, liver, gallbladder

Question 3

What is the function of the salivary glands?

Answer 3

squirt saliva (initiates digestion and protects teeth and other parts of the body) to moisten food to easily pass down the esophagus

Question 4

What is the function of the pancreas in the GI tract?

Answer 4

contributes pancreatic juices containing digestive enzymes via the pancreatic duct to the small intestine

Question 5

What is the function of the liver and gallbladder in the GI tract?

Answer 5

the liver produces bile (an emulsifier which prepares fats and oils for digestion) which is stored in the gallbladder and then squirted from there into the small intestine

Question 6

Compare/describe mechanical and chemical digestion.

Answer 6

Mechanical digestion involves physically breaking the food into smaller pieces, begins in the mouth as the food is chewed.

Chemical digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma (stomach), enzymes

Question 7

What are the secretions that break down fats in during digestion?

Answer 7

• pancreatic amylase
• salivary amylase
• maltase
• lactase

Question 8

What are the secretions that break down fats during digestion?

Answer 8

Bile and lipase (breaks down triglycerides into free fatty acids and monoglycerides)

Question 9

How does simple diffusion work?

Answer 9

Some nutrients (like water) are absorbed and cross into intestinal cells freely

Question 10

What are the 3 ways in which nutrients can be absorbed into the cells lining the GI tract following their digestion?

Answer 10

• Simple Diffusion
• Facilitated Transport
• Active Transport

Question 11

How does facilitated diffusion work?

Answer 11

Transports nutrients needing a specific carrier from one side of the cell membrane to the other (water-soluble vitamins) -> high to low concentration

Question 12

How does active transport work?

Answer 12

Carrier loads nutrients outside the cell and releases them inside the cell. Nutrients move against the concentration gradient, requiring more energy. (glucose and amino acids)

Question 13

What is the role of the circulatory (blood) system in the transport of nutrients around the body following their absorption?

Answer 13

Nutrients leaving the GI system via blood are routed to the liver before being transported to the body’s cells.

Question 14

What is the role of the lymphatic system in the transport of nutrients around the body following their absorption?

Answer 14

Nutrients leaving via the lymphatic system (large fats and fat-soluble vitamins) enter the vascular system (bypassing the liver first)

Question 15

What are the 3 major hormones that control digestion and absorption?

Answer 15

Gastrin (pH of stomach), secretin (pH of intestine), and cholecystokinin (gallbladder to release bile)

Question 16

What are the common digestive tract problems in humans?

Answer 16

Choking, vomiting, diarrhea, IBS, Colitis, Celiac, constipation, belching and gas, ulcers, etc.