Ch. 23-3 Digestive System Flashcards
What are the two major categories of the digestive system organs?
1) Alimentary Canal/Gastrointestinal Tract (GI) 2) Accessory Digestive Organs
List the organs included in the Alimentary Canal.
- Mouth
- Pharynx
- Esophagus
- Stomach
- Large intestine
- Small intestine
- Anus
What is the function of Accessory Digestive Organs?
Help process of digestion
List the organs classified as Accessory Digestive Organs.
- Mouth
- Tongue
- Gall bladder
- Salivary glands
- Pancreas
- Liver
What is the primary exocrine product of the pancreas?
Pancreatic juice
Where does pancreatic juice drain?
Into the duodenum via the main pancreatic duct
What does pancreatic juice contain?
- Enzymes that break down food
- Electrolytes
- Alkaline substances to neutralize chyme
What are acini in the pancreas?
Clusters of secretory acinar cells that store and secrete inactive digestive enzymes (zymogens)
What hormones do the Islets of Langerhans release?
- Insulin
- Glucagon
True or False: The pancreas is only an exocrine gland.
False
What are the major functions of the large intestine?
- Absorb water from remaining undigested food
- Temporarily store residue
- Secrete residues as feces
What is the length and diameter of the large intestine?
Approximately 1.5 m in length and 7 cm in diameter
What is the primary role of bacteria in the large intestine?
Harvest vitamins made by bacteria, reclaim remaining water and some electrolytes
List the four major subdivisions of the large intestine.
- Cecum
- Colon (ascending, transverse, descending, sigmoid)
- Rectum
- Anal canal
What are teniae coli?
Bands of smooth muscle in the large intestine
What are haustra?
Pouches formed by the tone of teniae coli in the large intestine
What triggers the relaxation of the ileocecal sphincter?
Gastroileum reflex caused by stomach activity and gastrin release
What type of epithelium is found in the mucosa of the large intestine?
Simple columnar epithelium, except in the anal canal
What is the function of goblet cells in the large intestine?
Secrete mucus to ease the passage of feces and protect the intestinal wall
What is the defecation reflex?
Parasympathetic stimulation causes contraction of sigmoid colon and rectum, and relaxation of internal anal sphincter
What is the role of beneficial bacteria in the large intestine?
- Synthesize B vitamins
- Metabolize host-derived molecules
- Ferment indigestible carbohydrates
What is digestion?
A catabolic process that breaks down large food molecules to monomers
What is required for the enzymatic breakdown of food molecules?
Hydrolysis
What initiates the digestion of carbohydrates?
Salivary amylase in the mouth
What enzymes are involved in the digestion of starches in the small intestine?
- Pancreatic amylase
- Dextrinase
- Lactase
- Maltase
- Sucrase
Where does protein digestion begin?
In the stomach with activated pepsin
What are the main enzymes that further cleave proteins in the small intestine?
- Trypsin
- Chymotrypsin
- Brush border enzymes (carboxypeptidase, amino- and di-peptidase)
What is the primary site for lipid digestion?
The small intestine
What role do bile salts play in lipid digestion?
Act as detergents to emulsify fats, making digestion more efficient
What is a gastric ulcer?
An erosion of the stomach wall causing gnawing epigastric pain
What commonly causes gastric ulcers?
Helicobacter pylori bacteria
What is gastritis?
An inflammation of the stomach lining
What is heartburn a symptom of?
Gastroesophageal reflux disease (GERD)
What causes appendicitis?
Acute inflammation resulting from a blockage, often by feces
What is diarrhea caused by?
Any condition that rushes food residue through the large intestine without sufficient time to absorb water
What is constipation?
When food remains in the colon for extended periods, causing hard stool
