Digestion and Absorption in the Small Intestine

Flashcards on the digestive system including mechanical and chemical digestion, absorption, and relevant anatomical structures.

Chyme

Liquidy mixture created in the stomach, containing partially digested carbohydrates and proteins.

Duodenum

The upper 5-10 inches of the small intestine, the primary site for digestion and absorption.

Jejunum

The middle region of the small intestine, located between the duodenum and ileum.

Ileum

The lower most region of the small intestine that communicates with the large intestine.

Mesentery

Extensions of parietal peritoneum that anchor the intestines to the abdominal cavity wall.

Greater Omentum

A large mesentery containing adipose tissue that lies over the intestinal bundle.

Hepatic Portal Vein

Vein that carries nutrient-rich blood from the digestive tract to the liver.

Plici Circulars

Permanent folds in the small intestine visible to the naked eye that increases surface area.

Villi

Microscopic folds in the mucosa of the small intestine, increasing surface area for absorption.

Microvilli

Folds in the apical membrane of columnar cells in the small intestine that increase surface area.

Intestinal Glands

Down folds of the villi that branch in all directions forming glandular regions.

Columnar Cells

Cells of the surface villi that function in absorption.

Goblet Cells

Cells that secrete mucus within the intestinal lining.

Intestinal Juice

Aqueous mixture with mucus and bicarbonate secreted in the intestinal glandular region.

Paneth Cells

Cells in the intestinal glands that secrete antimicrobial lysozyme and are phagocytic.

Enteroendocrine Cells

Hormone-producing cells in the GI tract.

Cholecystokinin (CCK)

Hormone that stimulates the digestion of fat and protein.

Secretin

A hormone that regulates water homeostasis throughout the body and influences the environment of the duodenum by regulating secretions in the stomach, pancreas, and liver

Mucosa Associated Lymphatic Tissue (MALT)

Lymphatic tissue in the submucosa of the small intestine that filters and traps pathogens.

Peristalsis

Propulsive movement that moves food through the small intestine.

Acini

Exocrine cells of the pancreas that form spherical clusters producing pancreatic juice.

Proteolytic Enzymes

Enzymes that break down proteins, produced in the pancreas.

Pancreatic Amylase

Enzyme that breaks down carbohydrates and is produced in the pancreas.

Pancreatic Lipase

Enzyme that breaks down triglycerides and is produced in the pancreas.

Bile

Produced in the liver, stored in the gallbladder, and contains bile salts

Bile Salts

Amphipathic emulsifiers derived from cholesterol that aid in the digestion of triglycerides.

Segmentation

Random asynchronous contractions in the small intestine that mix chyme with intestinal juices, pancreatic juice, and bile.

Disaccharidases

Membrane enzymes in the small intestine that break down disaccharides into monosaccharides.

Emulsification

Breaking up a large fat globule into smaller ones using bile salts and lecithin.

Micelles

Transport vesicles that carry free fatty acids, glycerol, and monoglycerides across the apical surface of absorptive cells.

Chylomicrons

Structures formed by resynthesized triglycerides surrounded by amphipathic proteins that exit the basal surface of absorptive cells.

Lacteal

Lymphatic capillary in the center of a villus that absorbs chylomicrons.

Secondary Active Transport

Process by which glucose is absorbed in the small intestine surface.