Digestion and Absorption

Question 1

What is the process of digestion?

Answer 1

Digestion is the process of breaking down ingested food into smaller molecules that can be absorbed and utilized by the body.

Question 2

Where does digestion primarily occur in the human body?

Answer 2

Digestion primarily occurs in the gastrointestinal tract, including the mouth, stomach, and small intestine.

Question 3

Describe mechanical digestion and its role in digestion.

Answer 3

Mechanical digestion involves physical processes such as chewing and mixing that break down food into smaller particles, increasing its surface area for chemical digestion.

Question 4

What are the enzymes involved in chemical digestion of carbohydrates, and what do they break down?

Answer 4

The enzymes involved in the chemical digestion of carbohydrates are salivary amylase and pancreatic amylase, which break down carbohydrates into simpler sugars like glucose.

Question 5

What enzyme breaks down proteins during digestion, and where is it primarily produced?

Answer 5

The enzyme responsible for protein digestion is pepsin, primarily produced in the stomach as pepsinogen, which is activated by gastric acid.

Question 6

What enzymes are responsible for lipid digestion, and what do they break down?

Answer 6

Lipid digestion is carried out by enzymes such as lingual lipase, gastric lipase, and pancreatic lipase, which break down lipids into fatty acids and glycerol.

Question 7

Where does the digestion of carbohydrates begin, and which enzyme initiates it?

Answer 7

Carbohydrate digestion begins in the mouth with salivary amylase, which breaks down starches into maltose.

Question 8

What enzyme continues the digestion of carbohydrates in the small intestine, and where is it produced?

Answer 8

In the small intestine, carbohydrate digestion continues with pancreatic amylase, produced by the pancreas.

Question 9

Describe the digestion of proteins, including the role of pepsin and trypsin.

Answer 9

Protein digestion involves pepsin in the stomach, breaking proteins into peptides, and trypsin in the small intestine, further breaking down peptides into amino acids.

Question 10

Where does lipid digestion primarily occur, and what enzymes are involved?

Answer 10

Lipid digestion primarily occurs in the small intestine, with lingual and gastric lipases in the stomach and pancreatic lipase in the small intestine.

Question 11

Describe the action of bile salts in lipid digestion.

Answer 11

Bile salts emulsify lipids, breaking them into smaller droplets to increase their surface area for digestion by lipases.

Question 12

What are micelles, and what is their role in lipid absorption?

Answer 12

Micelles are small aggregates of bile salts and lipids that enhance the absorption of lipids in the small intestine.

Question 13

Describe the process of absorption in the small intestine.

Answer 13

Absorption in the small intestine involves the uptake of digested nutrients across the epithelial lining into the bloodstream or lymphatic system.

Question 14

What are villi and microvilli, and how do they enhance absorption in the small intestine?

Answer 14

Villi are finger-like projections in the small intestine, and microvilli are smaller projections on the surface of absorptive cells, increasing the surface area for absorption.

Question 15

What are the main nutrients absorbed in the small intestine?

Answer 15

The main nutrients absorbed in the small intestine include carbohydrates, proteins, lipids, vitamins, minerals, water, and electrolytes.

Question 16

How are carbohydrates absorbed in the small intestine?

Answer 16

Carbohydrates are absorbed in the small intestine primarily as monosaccharides like glucose and fructose via active transport and facilitated diffusion.

Question 17

How are proteins absorbed in the small intestine?

Answer 17

Proteins are absorbed in the small intestine as amino acids via active transport or facilitated diffusion.

Question 18

How are lipids absorbed in the small intestine?

Answer 18

Lipids are absorbed in the small intestine as fatty acids and glycerol, primarily via diffusion and absorption into the lymphatic system.

Question 19

What are lacteals, and what do they absorb?

Answer 19

Lacteals are lymphatic vessels in the small intestine that absorb dietary fats and fat-soluble vitamins.

Question 20

Describe the absorption of water and electrolytes in the small intestine.

Answer 20

Water and electrolytes are absorbed throughout the small intestine via osmosis, passive diffusion, and active transport.

Question 21

Where does absorption of water primarily occur in the gastrointestinal tract?

Answer 21

Absorption of water primarily occurs in the small intestine, especially in the jejunum and ileum.

Question 22

What is the role of passive diffusion in nutrient absorption?

Answer 22

Passive diffusion allows nutrients to move across the epithelial membrane down their concentration gradient without requiring energy.

Question 23

Describe facilitated diffusion and its role in absorption.

Answer 23

Facilitated diffusion involves the movement of nutrients across the epithelial membrane with the help of carrier proteins but does not require energy.

Question 24

What is active transport, and how does it contribute to nutrient absorption?

Answer 24

Active transport requires energy to move nutrients against their concentration gradient across the epithelial membrane, often utilizing carrier proteins.

Question 25

What role do sodium-glucose co-transporters (SGLTs) play in nutrient absorption?

Answer 25

Sodium-glucose co-transporters (SGLTs) actively transport glucose and galactose across the epithelial membrane into absorptive cells, coupled with the movement of sodium ions.

Question 26

How does the absorption of vitamins and minerals occur in the small intestine?

Answer 26

Absorption of vitamins and minerals occurs through various mechanisms, including active transport, passive diffusion, and facilitated diffusion.

Question 27

Describe the absorption of fat-soluble vitamins.

Answer 27

Fat-soluble vitamins (A, D, E, K) are absorbed along with dietary lipids and are transported in chylomicrons.

Question 28

What is the significance of the hepatic portal system in nutrient absorption?

Answer 28

The hepatic portal system transports absorbed nutrients from the small intestine to the liver for processing and storage before entering the systemic circulation.

Question 29

How are nutrients transported from the small intestine to the liver?

Answer 29

Nutrients absorbed in the small intestine are transported via the hepatic portal vein to the liver, where they undergo further metabolism or are stored.

Question 30

Describe the role of the lymphatic system in lipid absorption.

Answer 30

The lymphatic system plays a crucial role in lipid absorption, transporting absorbed lipids as chylomicrons via lacteals to the bloodstream.