Digestive System - Anatomy and Physiology

Alimentary Canal/GI Tract

the whole passage where food passes through the body through mouth to anus

• includes mouth, pharynx, esophagus, stomach (small duodenum, jejunum, ileum) intestine and large intestine/colon (ascending, transverse, descending, sigmoid, cecum, appendix), rectum, anus

Accessory Structures

organs that aid in breaking down food

• salivary glands, gallbladder, liver, pancreas, peritoneum (mesentery)

Peritoneum/Mesentary

• large structure lining the abdominal cavity

• serous membrane (type of membrane it is)

• mesentary is folds that attaches to the intestine

Mouth

• where digestion starts

• responsible for chewing, ingestion, and mechanical processing

Saliva

• contains chemical compounds that break down food in mouth

Pharynx

• bolus passes through this passageway (bolus is softened food from chewing)

• also known as throat

Uvula

• folds back to block food from going down nose and into the laryngopharynx

Epiglottis

• flap of tissue that closes opening to the larynx and trachea

Peristalsis

• wave like involuntary muscle movement that helps bolus pass through pharynx and esophagus

Stomach

• first place where chemical digestion takes place

• food enters through cardiac sphincter (helps prevents food from going back UP into esophagus)

Cardia

• attached to both esophagus and stomach and helps produce mucus

Fundus

• located on top of the stomach that produces pepsin and HCl (hydrogen chloride)

Body

• main part of the stomach that helps produce pepsin and HCl (hydrogen chloride)

Plyoric

• bottom part of stomach that attaches to the duodenum and helps produce mucus

Chyme

• partially digested food inside the stomach

• made of acid, mixture of food, and mucus

Pyloric sphinter

• helps opening region between small intestine and stomach and opens and closes to release chyme into small intestine

Duodenum

• where most digestion occurs in small intestine

• RECIEVES secretions from gallbladder and pancreas

Jejunum

• apart of small intestine

Ileum

last segment of the small intestine

Liver

• produces bile salts

Pancreas

• large gland behind stomach (skinny in frogs)

• secretes digestive enzymes into the duodenum

Gallbladder

• STORES bile in pouch located under liver

Cecum

• pouch in the first part of the large intestine and attached to the “thin” appendix

Appendix

• dead end pouch that looks like a snake/thin structure attached to cecum

Ascending colon

• attached to the cecum and below the right colic flexure

Transverse Colon

• above and parallel to the rectum and anus and after right colic flexure

Descending Colon

• connected to the left colic flexure and after the transverse colon

• going down—> “hence the name DESCENDING!”

Sigmoid colon

• the last part of the large intestine before it reaches the rectum

Rectum

• final section of large intestine where colon travels through

• stores feces

Anus

• opening where solid mass leaves the body at the end of the GI tract

Q: Which parts of the alimentary canal or GI tract are specifically functioning to absorb contents and nutrients?

small intestine and stomach

A

stomach

B

Pancreas

C

Liver

D

Lungs

E

Heart

What is the name of the sphincter that regulates the exit of food from the stomach to the duodenum?

Pyloric Sphinter

What is stored in the gallbladder and what is its function?

The gallbladder stores bile and helps break down fat

What is the cloaca?

The cavity at the end of the GI tract

Explain where in the digestive tract proteins are broken down and which enzymes are used. Give 2 examples.

The stomach breaks down the enzyme pepsin and the duodenum breaks down enzymes such as lactase, sucrase, and maltase

The SMALL INTESTINE mainly absorbs…

nutrients

The LARGE INTESTINE mainly absorbs…

water