Digestion and Absorption Flashcards
What is the process of digestion?
Digestion is the process of breaking down ingested food into smaller molecules that can be absorbed and utilized by the body.
Where does digestion primarily occur in the human body?
Digestion primarily occurs in the gastrointestinal tract, including the mouth, stomach, and small intestine.
Describe mechanical digestion and its role in digestion.
Mechanical digestion involves physical processes such as chewing and mixing that break down food into smaller particles, increasing its surface area for chemical digestion.
What are the enzymes involved in chemical digestion of carbohydrates, and what do they break down?
The enzymes involved in the chemical digestion of carbohydrates are salivary amylase and pancreatic amylase, which break down carbohydrates into simpler sugars like glucose.
What enzyme breaks down proteins during digestion, and where is it primarily produced?
The enzyme responsible for protein digestion is pepsin, primarily produced in the stomach as pepsinogen, which is activated by gastric acid.
What enzymes are responsible for lipid digestion, and what do they break down?
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.
Where does the digestion of carbohydrates begin, and which enzyme initiates it?
Carbohydrate digestion begins in the mouth with salivary amylase, which breaks down starches into maltose.
What enzyme continues the digestion of carbohydrates in the small intestine, and where is it produced?
In the small intestine, carbohydrate digestion continues with pancreatic amylase, produced by the pancreas.
Describe the digestion of proteins, including the role of pepsin and trypsin.
Protein digestion involves pepsin in the stomach, breaking proteins into peptides, and trypsin in the small intestine, further breaking down peptides into amino acids.
Where does lipid digestion primarily occur, and what enzymes are involved?
Lipid digestion primarily occurs in the small intestine, with lingual and gastric lipases in the stomach and pancreatic lipase in the small intestine.
Describe the action of bile salts in lipid digestion.
Bile salts emulsify lipids, breaking them into smaller droplets to increase their surface area for digestion by lipases.
What are micelles, and what is their role in lipid absorption?
Micelles are small aggregates of bile salts and lipids that enhance the absorption of lipids in the small intestine.
Describe the process of absorption in the small intestine.
Absorption in the small intestine involves the uptake of digested nutrients across the epithelial lining into the bloodstream or lymphatic system.
What are villi and microvilli, and how do they enhance absorption in the small intestine?
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.
What are the main nutrients absorbed in the small intestine?
The main nutrients absorbed in the small intestine include carbohydrates, proteins, lipids, vitamins, minerals, water, and electrolytes.
How are carbohydrates absorbed in the small intestine?
Carbohydrates are absorbed in the small intestine primarily as monosaccharides like glucose and fructose via active transport and facilitated diffusion.
How are proteins absorbed in the small intestine?
Proteins are absorbed in the small intestine as amino acids via active transport or facilitated diffusion.
How are lipids absorbed in the small intestine?
Lipids are absorbed in the small intestine as fatty acids and glycerol, primarily via diffusion and absorption into the lymphatic system.
What are lacteals, and what do they absorb?
Lacteals are lymphatic vessels in the small intestine that absorb dietary fats and fat-soluble vitamins.
Describe the absorption of water and electrolytes in the small intestine.
Water and electrolytes are absorbed throughout the small intestine via osmosis, passive diffusion, and active transport.
Where does absorption of water primarily occur in the gastrointestinal tract?
Absorption of water primarily occurs in the small intestine, especially in the jejunum and ileum.
What is the role of passive diffusion in nutrient absorption?
Passive diffusion allows nutrients to move across the epithelial membrane down their concentration gradient without requiring energy.
Describe facilitated diffusion and its role in absorption.
Facilitated diffusion involves the movement of nutrients across the epithelial membrane with the help of carrier proteins but does not require energy.
What is active transport, and how does it contribute to nutrient absorption?
Active transport requires energy to move nutrients against their concentration gradient across the epithelial membrane, often utilizing carrier proteins.
