📘 CHAPTER 18: DIGESTIVE SYSTEM – MASTER REVIEW

What are the main goals of the digestive system?

Ingestion, digestion, absorption, elimination.

What is ingestion in the context of the digestive system?

Taking in food.

What two processes make up digestion?

Mechanical (chewing) and chemical (enzymes).

What is absorption in the digestive system?

Nutrients move into blood/lymph.

What is elimination in relation to the digestive system?

Removal of undigested food as feces.

What is the alimentary canal?

A continuous tube from mouth to anus.

Can you name the parts of the alimentary canal?

Mouth, pharynx, esophagus, stomach, small intestine, large intestine.

What are accessory organs in the digestive system?

Organs that aid digestion but do not pass food through them.

Can you list the accessory organs?

Teeth, tongue, salivary glands, liver, gallbladder, pancreas.

What is the role of the mucosa in the digestive tract?

Secretes mucus and enzymes; absorbs nutrients.

What is the submucosa composed of?

Blood vessels and nerves.

What is the muscularis layer responsible for?

Movement through peristalsis and segmentation.

What is the serosa?

The outer covering of the digestive tract.

What types of teeth are present in the mouth?

Incisors, canines (cuspids), and molars/premolars.

What is the function of incisors?

To cut food.

What do canines do?

Tear food.

What is the role of molars and premolars?

Grind food.

What are the functions of the tongue?

Helps position food (bolus) and aids in swallowing.

What are the three types of salivary glands?

Parotid, submandibular, and sublingual.

What enzyme in saliva begins carbohydrate digestion?

Salivary amylase.

What is the esophagus?

A muscular tube that transports food from pharynx to stomach.

What is the function of the upper esophageal sphincter (UES)?

Blocks air from entering the esophagus.

What does the lower esophageal sphincter (LES) prevent?

Prevents acid reflux.

What condition results from LES failure?

GERD (gastroesophageal reflux disease).

What is a hiatal hernia?

Stomach protrudes through the diaphragm.

What does Barrett esophagus indicate?

A precancerous condition resulting from chronic GERD.

What are the regions of the stomach?

Cardia, fundus, body, pylorus.

What is the function of the stomach?

Churns food into chyme and starts protein digestion.

What enzyme is activated by hydrochloric acid (HCl) in the stomach?

Pepsin.

What is intrinsic factor necessary for?

Vitamin B₁₂ absorption.

What are common conditions affecting the stomach?

Gastritis, gastric ulcer, pyloric stenosis.

What is the primary function of the small intestine?

Main site for nutrient absorption.

What are the segments of the small intestine?

Duodenum, jejunum, ileum.

What happens in the duodenum?

It receives enzymes and bile.

What is the jejunum known for?

Major absorption of nutrients.

What is absorbed in the ileum?

Vitamin B₁₂ and bile salts.

What structures enhance absorption in the small intestine?

Plica, villi, and microvilli.

What functions do microvilli serve?

They are projections on epithelial cells that increase surface area for absorption.

What enzymes are produced in the small intestine?

Amylase, lipase, peptidase/trypsin, sucrase/lactase.

What condition results from inflammation of the small intestine?

Enteritis.

What does gastroenteritis affect?

It affects both the stomach and small intestine.

What is malabsorption syndrome?

A condition where nutrients are not absorbed effectively.

What does maldigestion indicate?

Deficiency of enzymes/bile.

What are the major functions of the liver?

Makes bile, detoxifies blood, processes nutrients, stores glycogen and vitamins.

Where is bile stored?

In the gallbladder.

What hormone triggers the release of bile?

CCK (cholecystokinin).

How does the pancreas function in digestion?

Produces enzymes for digestion of carbs, fats, and proteins.

What hormones does the pancreas secrete?

Insulin and glucagon.

What are gallstones?

Concretions that form in the gallbladder.

What is choledocholithiasis?

Stones in the bile duct.

What is pancreatitis?

Inflammation of the pancreas.

What is colorectal cancer?

Cancer that occurs in the colon or rectum.

What are the segments of the large intestine?

Cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anal canal.

What are the primary functions of the large intestine?

Absorbs water, salts, vitamin K, and houses gut microbiome.

What conditions can affect the large intestine?

Diarrhea, constipation, diverticulosis, colitis, Crohn's disease, ulcerative colitis.

What is the function of the appendix?

Has an immune function.

What is peritonitis?

Inflammation of the peritoneum, often from a ruptured appendix.

What is the peritoneum?

A serous membrane surrounding abdominal organs.

What is the difference between visceral and parietal peritoneum?

Visceral is on the organs; parietal is on cavity walls.

What is an extension of the peritoneum that holds intestines in place?

Mesentery.

What does the greater omentum do?

Acts as a fatty 'lace apron' covering the intestines.

What are the end products of carbohydrate digestion?

Glucose.

What are the end products of protein digestion?

Amino acids.

What are the end products of fat digestion?

Fatty acids and glycerol.

How do monosaccharides, amino acids, minerals, vitamins, and water enter the bloodstream?

Through blood capillaries.

How do fatty acids and glycerol enter the body?

Through lacteals (lymph).

What are the processes by which nutrients enter the body?

Active transport, osmosis, diffusion.

What key thing is noted about digestion starting in the mouth?

Digestion begins with salivary amylase.

Where does protein digestion begin?

In the stomach with pepsin.

Which organ is responsible for most nutrient absorption?

Small intestine.

Where is bile made and stored?

Made in the liver, stored in the gallbladder.

What enhances absorption in the small intestine?

Villi and microvilli.

What does the large intestine primarily absorb?

Water and vitamin K.

What condition signifies a problem with the lower esophageal sphincter?

GERD.

What does CCK trigger?

The release of bile.

What are the roles of pepsin, lipase, and amylase?

Pepsin digests proteins, lipase digests fats, amylase digests carbohydrates.

What are the three final products of digestion?

Carbohydrates into glucose, proteins into amino acids, fats into fatty acids and glycerol.