exam 4 (only digestive and urinary for now)

What organs make up the lower gastrointestinal tract?

Small intestine and large intestine.

What are the three regions of the small intestine?

Duodenum, jejunum, ileum.duplicate

Where does most chemical digestion and absorption occur?

Duodenum and jejunum of the small intestine.

What organ produces bile?

The liver.

What organ stores, concentrates, and releases bile?

The gallbladder.

What organ produces pancreatic juice?

The pancreas.

What does the large intestine primarily absorb?

Water, electrolytes, and some vitamins.

What is the final product formed in the large intestine?

Feces

What is Crohn disease?

An autoimmune inflammatory bowel disease causing intermittent cramping and diarrhea anywhere in the gastrointestinal tract.

What is ulcerative colitis?

An autoimmune inflammatory bowel disease affecting only the large intestine with continuous inflammation.

What is irritable bowel syndrome?

A functional disorder of the large intestine with no inflammation or tissue damage.

How long do nutrients remain in the small intestine?

At least 12 hours.

What are the three segments of the small intestine?

Duodenum, jejunum, ileum.

What shape is the duodenum?

C‑shaped around the head of the pancreas.

What is the duodenojejunal flexure?

The junction between the duodenum and jejunum.

What is the primary function of the jejunum?

Chemical digestion and nutrient absorption.

What is the ileocecal valve?

A sphincter controlling entry of materials into the large intestine.

What are circular folds?

Internal folds of mucosa and submucosa that increase surface area and slow chyme movement.

Where are circular folds most numerous?

Duodenum and jejunum.

What are villi?

Fingerlike projections of mucosa that increase absorption.

What is a lacteal?

A lymphatic capillary in a villus that absorbs lipids and lipid‑soluble vitamins.

What are microvilli?

Microscopic extensions of epithelial cells forming the brush border with digestive enzymes.

What are intestinal glands?

Invaginations between villi that secrete intestinal juice.

What do goblet cells secrete? .

Mucin, which becomes mucus

What do enteroendocrine cells secrete?

Hormones such as cholecystokinin and secretin.

What do Paneth cells secrete?

Lysozyme and antimicrobial substances.

What do duodenal submucosal glands secrete?

Alkaline mucus to protect from acidic chyme.

Which small intestine region has the best circular folds and largest villi?

The jejunum.

Which small intestine region has many lymphoid nodules?

The ileum.

What is segmentation?

Back‑and‑forth mixing of chyme with secretions.

What is peristalsis?

Wave‑like contractions that move chyme forward.

What hormone stimulates migrating motor complexes?

Motilin

What is the biliary apparatus?

A network of ducts that transport bile from the liver and gallbladder to the duodenum.

What forms the common bile duct?

The common hepatic duct and cystic duct.

Where do the common bile duct and main pancreatic duct merge?

At the hepatopancreatic ampulla.

What is the major duodenal papilla?

The opening where bile and pancreatic juice enter the duodenum.

What is the main function of the liver?

Production of bile.

What separates the right and left lobes of the liver?

The falciform ligament.

What is the porta hepatis?

The entry/exit site for blood vessels, lymph vessels, bile ducts, and nerves.

What are hepatic lobules?

Functional units of the liver containing hepatocytes.

What is the portal triad composed of?

A bile ductule, a branch of the hepatic portal vein, and a branch of the hepatic artery.

What are Kupffer cells?

Stellate macrophages in liver sinusoids that remove harmful substances.

What do bile salts do?

Emulsify lipids.

What does the gallbladder do?

Stores, concentrates, and releases bile.

What are gallstones?

Solidified bile components that may block ducts.

What is the endocrine function of the pancreas?

Secretion of insulin and glucagon.

What is the exocrine function of the pancreas?

Secretion of pancreatic juice containing digestive enzymes.

What do acinar cells produce?

Digestive enzymes.

What do pancreatic duct cells secrete?

Alkaline bicarbonate fluid.

What enzymes are found in pancreatic juice?

Pancreatic amylase, pancreatic lipase, inactive proteases, and nucleases.

What does cholecystokinin stimulate?

Gallbladder contraction, pancreatic enzyme release, and relaxation of the hepatopancreatic sphincter.

What does secretin stimulate?

Release of alkaline secretions from the liver and pancreas.

What are the functions of the large intestine?

Absorb water and electrolytes, compact chyme into feces, and store feces.

What is the cecum?

The first part of the large intestine receiving chyme from the ileum.

What is the vermiform appendix?

A thin sac containing lymphoid nodules that may store beneficial bacteria.

What are the four segments of the colon?

Ascending, transverse, descending, and sigmoid colon.

What is the rectum?

A muscular tube that stores feces.

What is the anal canal lined with?

Stratified squamous epithelium.

What are anal sinuses?

Depressions that release mucus when compressed.

What is the internal anal sphincter?

Involuntary smooth muscle.

What is the external anal sphincter?

voluntary skeletal muscle.

What are teniae coli?

Three thin longitudinal muscle bands in the large intestine.

What are haustra?

Sac‑like pouches formed by teniae coli.

What are omental appendices?

Fatty tags on the large intestine.

What type of epithelium lines the large intestine?

Simple columnar epithelium with many goblet cells.

Does the large intestine have villi?

No, it lacks villi.

What are intestinal glands in the large intestine responsible for?

Secreting mucin for lubrication.

What is the gut microbiome?

Bacterial flora in the large intestine that help digest nutrients and produce vitamins.

What vitamins does the gut microbiome produce?

B vitamins and vitamin K.

What is feces composed of?

Water, salts, epithelial cells, bacteria, and undigested material.

What is a fecal transplant?

Transfer of healthy donor stool to restore gut microbiota.

What is haustral churning?

Slow mixing movement in the large intestine.

What are mass movements?

Powerful contractions that move fecal material toward the rectum.

What triggers the gastrocolic reflex?

Stomach distension.

What triggers the defecation reflex?

Rectal stretch receptors activated by filling.

What happens during the defecation reflex?

Parasympathetic output increases colon contraction and relaxes the internal anal sphincter.

What is voluntary defecation dependent on?

Relaxation of the external anal sphincter and the Valsalva maneuver.

What causes constipation?

Slow movement of feces with excessive water absorption.

What causes diarrhea?

Rapid movement of feces with insufficient water absorption.

What are nutrients?

Molecules and ions needed for metabolism and life.

What begins carbohydrate digestion?

Salivary amylase.

What completes carbohydrate digestion?

Brush border enzymes such as maltase and lactase.

What are the final products of carbohydrate digestion?

Monosaccharides.

What begins protein digestion?

Hydrochloric acid and pepsin in the stomach.

What completes protein digestion?

Pancreatic enzymes and brush border peptidases.

What are the final products of protein digestion?

Amino acids.

What activates lingual lipase?

Stomach acid.

What percentage of triglycerides does gastric lipase digest?

About 30 percent.

What emulsifies lipids?

Bile salts.

What enzyme digests triglycerides in the small intestine?

Pancreatic lipase.

What are micelles?

Structures formed by bile salts that transport lipids to epithelial cells.

What are chylomicrons?

Lipid‑protein particles that transport triglycerides into lacteals.

What enzymes digest nucleic acids?

Pancreatic nucleases and brush border enzymes.

What are the final products of nucleic acid digestion?

Phosphate, sugar, and nitrogenous bases.

How is most water absorbed?

By osmosis in the small intestine.

What hormone inhibits iron absorption?

Hepcidin

How are fat‑soluble vitamins absorbed?

With lipids in micelles.

How are water‑soluble vitamins absorbed?

By diffusion or active transport.

What vitamin requires intrinsic factor for absorption?

Vitamin B12.

Where is intrinsic factor produced?

Parietal cells of the stomach.