Human Physiology - The Digestive System

Flashcards covering key concepts from the digestive system lecture, including anatomy, processes, secretions, digestion/absorption, regulation, and immune functions.

List the major organs of the digestive system.

Oral cavity, salivary glands, esophagus, pancreas, stomach, small intestine, rectum, large intestine, gallbladder, liver

What are the four basic processes of the digestive system?

Digestion, absorption, secretion, motility

What are the two main purposes of GI motility?

Moving food through the tract & Mechanically mixing food to break it into uniformly small particles

Name the three patterns of contraction in the gastrointestinal smooth muscle.

Migrating motor complex, peristalsis, and segmentation

What are the main components of saliva?

Water, mucus, enzymes (lysozymes and amylase), antibodies

What are the main components of bile?

Bile salts (emulsifiers), bilirubin (waste of hemoglobin degradation), cholesterol

Salivary Amylase in mouth digests Carbohydrates in what way?

Starch, Glycogen and other Polysaccharides > Disaccharides

Carbohydrate- absorption is limited to what?

Absorption limited to Monosaccharides only

What is needed Carbohydrate to enter Enterocytes of Jejunum and Ileum

Na+K+ATPase, and GLUT on Basolateral membrane and SGLT on Apical for glucose to enter Enterocytes of Jejunum and Ileum

Name the endopeptidases involved in protein digestion.

Pepsin in the stomach, and trypsin and chymotrypsin in the small intestine.

What creates a micelle?

Bile salts (emulsifiers), lipase (from pancreas), lipids

A micelle diffuses into what and combines with Cholesterol to create what?

Micelle diffuses into Enterocytes and combines with Cholesterol to create Chylomicrons

Where are most Vitamins and minerals absorbed ?

Jejunum and Ileum

Where does water absorption occur and how?

Enterocytes and Colonocytes actively absorb Na+

What secretion happens in the Oral Cavity and Esophagus?

Saliva (salivary glands)

What secretion happens in the Stomach?

HCl (parietal cells), Pepsinogen and gastric lipase (chief cells), Mucus and bicarbonate (surface mucous cells), Gastrin (G cells), Histamine (ECL cells)

What secretion happens in the Small Intestine?

Enzymes (enterocytes), Mucus (goblet cells), Hormones: CCK, secretin, GIP, and others (endocrine cells), Enzymes and bicarbonate (exocrine pancreas), Bile (liver, stored in gallbladder)

What secretion happens in the Large Intestine?

Mucus (goblet cells)

What does Salivary Amylase breakdown in the Cephalic Phase?

Salivary Amylase partially hydrolyzes starch (and other polysaccharides) into disaccharides.

What are the three functions of the stomach in the gastric phase?

Storage, chemical and mechanical digestion, protection

Name three roles of hydrochloric acid in the stomach.

Kills bacteria, denatures proteins, activates pepsinogen into pepsin

What secretions happen in the Duodenum in the Intestinal Phase?

Bicarbonate from the pancreas, mucus, bile, hydrolases from duodenum and pancreas

Where does absorption occur in the Intestinal Phase?

Jejunum and Ileum

Absorbed AAs, peptides and monosaccharides are transported to which organ?

Liver via Hepatic Portal vein

What is the livers chief metabolic/anabolic function?

Determines if monomers should be rearranged into new polymers (anabolic)

What is Hepatic Clearance?

Hepatocytes contain enzymes that breakdown some drugs, toxins and metabolites clears them from the bloodstream

What is the main job of the Colon?

The main job of the Colon is to concentrate undigested waste via water absorption.

Name two Gut-Associated Lymphoid Tissues (GALT)

Peyer's Patches, Lacteal (in Villi)

What are the two different types of Diarrhea?

Osmotic and Secretory