Generated digestive system questions

Parts of the digestive tract

Mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus; accessory organs include salivary glands, liver, pancreas, gallbladder.

Layers of the wall of the GI tract

Mucosa, submucosa, muscularis, serosa

Inner lining epithelium of the GI tract

Simple columnar epithelium; esophagus has stratified squamous epithelium.

Functions of villi and microvilli

Increase surface area for absorption in the small intestine.

Sympathetic nerve stimulation on GI motility

Inhibits motility and secretions; prepares body for 'fight or flight'.

Parasympathetic nerve stimulation on GI motility

Stimulates motility and secretions; promotes 'rest and digest' functions.

Peristalsis

Wave-like muscle contractions that move food through the GI tract, occurring throughout the digestive system.

Mixing movements

Churning movements that blend food with digestive juices, primarily in the stomach.

Segmentation movements

Rhythmic contractions that mix food in the small intestine, enhancing absorption.

Mass movements

Strong peristaltic waves that move waste toward the rectum, primarily in the large intestine.

Phases of swallowing

Oral phase, pharyngeal phase, esophageal phase.

Salivary glands

Parotid, sublingual, submandibular; produce saliva containing amylase, mucin, and antibacterial compounds.

Functions of saliva

Moistens food, begins digestion of carbohydrates, contains antibacterial agents.

Function of the esophagus

Transports food from the pharynx to the stomach; lower esophageal sphincter prevents acid reflux.

Condition from loose lower esophageal sphincter

Gastroesophageal reflux disease (GERD).

Parts of the stomach

Cardia, fundus, body, pylorus.

Functions of the stomach

Stores food, begins digestion of proteins, regulates the passage of food to the small intestine.

Composition of gastric juice

Hydrochloric acid, pepsin, intrinsic factor, mucous.

Functions of components of gastric juice

Acidic environment for digestion, protein digestion (pepsin), absorption of vitamin B12 (intrinsic factor), mucus protects the stomach lining.

Importance of the gastric mucosal barrier

Protects the stomach lining from acidic gastric juice and prevents ulcers.

Condition from intrinsic factor deficiency

Pernicious anemia.

Factors disrupting gastric mucosal barrier

NSAIDs, alcohol, H. pylori infection, excessive acid production.

Factors controlling gastric secretion

Neural (vagal stimulation), hormonal (gastrin), local factors (food presence).

Three phases of gastric secretion

Cephalic phase, gastric phase, intestinal phase; gastric juice is maximally secreted during the gastric phase.

Hormone that stimulates gastric secretion

Gastrin; secreted from gastric mucosa.

Composition of pancreatic juice

Digestive enzymes (amylase, lipase, proteases), bicarbonate.

Functions of components of pancreatic juice

Amylase for carbohydrate digestion, lipase for fat digestion, proteases for protein digestion, bicarbonate for neutralizing stomach acid.

Hormones controlling pancreatic secretion

Secretin (stimulates bicarbonate secretion), cholecystokinin (stimulates enzyme secretion).

Release location of secretin and cholecystokinin

Secretin is released from the small intestine; cholecystokinin is released from the small intestine.

Stimulus for secretin release

Acidic chyme entering the small intestine.

Stimulus for cholecystokinin release

Fats and proteins entering the small intestine.

Inactivity of protein-digesting enzymes

Prevent autodigestion; activated in the small intestine by enterokinase.

Components of bile

Bile salts, cholesterol, bilirubin, electrolytes.

Functions of bile

Emulsifies fats, aids in fat digestion and absorption.

Emulsification of fats

Process of breaking down large fat globules into smaller droplets to enhance digestion.

Action of cholecystokinin on bile secretion

Stimulates gallbladder contraction to release bile into the small intestine.

Part of small intestine bile is released into

Duodenum.

Parts of the small intestine

Duodenum, jejunum, ileum.

Maximum digestion and absorption site in small intestine

Jejunum.

Enzymes on microvilli of small intestine

Disaccharidases, peptidases, and enterokinase.

Parts of the large intestine

Cecum, colon (ascending, transverse, descending, sigmoid), rectum, anus.

Functions of the large intestine

Absorbs water and electrolytes, forms and stores feces.

Digestion and absorption of carbohydrates

Involves salivary amylase, pancreatic amylase, and brush border enzymes; absorbed as monosaccharides.

Digestion and absorption of proteins

Involves pepsin and pancreatic proteases; absorbed as amino acids.

Digestion and absorption of fats

Requires bile and lipases; absorbed as fatty acids and glycerol.

Lactose intolerance

Inability to digest lactose due to deficiency of lactase.

Digestion and absorption of fats in small intestine

Involves emulsification by bile and breakdown by lipases for absorption of fatty acids.

Digestion and absorption of disaccharides

Broken down into monosaccharides (glucose, fructose, galactose) by specific enzymes on the brush border.