The Digestive System

Anatomy and Physiology Chapter 15

What is the overall function of the digestive stystem?

To take in food, break it down into nutrients, absorb nutrients into the bloodstream, and remove indigestible waste

What are the two main groups of digestive organs?

The alimentary canal (GI tract) and accessory digestive organs

What organs make up the alimentary canal?

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

What are accessory digestive organs?

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

What is ingestion?

Taking food into the digestive tract

What is propulsion?

Movement of food through the GI Tract via swallowing and peristalsis

What is peristalsis?

Alternating waves of muscle contraction and relaxation that move food forward

What is mechanical digestion?

Physical breakdown of food (chewing, churning, segmentation)

What is chemical digestion?

Enzymatic breakdown of food into absorbable molecules

What is absorption?

Movement of digested nutrients into blood or lymph

What is defecation?

Elimination of indigestible wastes as feces

What are the four layers of the alimentary canal (inner to outer)?

Mucosa, Submucosa, muscularis externa, serosa

What are the main functions of the mucosa?

Secretion, absorption and protection

Which layer is responsible for peristalsis and segmentation?

Muscularis externa

What is the serosa?

The outer protective layer (visceral peritoneum)

What digestive processes occur in the mouth?

Ingestion, mechanical digestion, propulsion, and chemical digestion of carbohydrates

What is mastication?

chewing

What is bolus?

A mass of chewed food mixed with saliva

What enzyme is found in saliva?

Salivary amylase

What does salivary amylase digest?

Starches (Carbohydrates)

What are the 3 major salivary glands?

Parotid, Submandibular, sublingual

Which salivary gland can be affected by mumps?

Parotid gland

How many primary (baby) teeth are there?

20

How many permanent teeth are there?

32

What are the four types of teeth and their functions

Incisors: cut

Canines: tear

Premolars & molars: crush and grind

What is enamel?

The hardest substance in the body that covers the crown

What is dentin?

Bonelike tissue beneath enamel that makes up most of the tooth

What is the function of the pharynx?

Connects the mouth to the esophagus

What is the function of the esophagus?

Transports food to the stomach

What sphincter connects the esophagus to the stomach?

Cardiac (esophageal) spincter

What is the main functions of the stomach?

Protein digestion and conversion of food into chyme

What is chyme?

A semi-liquid mixture of partially digested food

What are regae?

Folds in the stomach that allow expansion

What extra muscle layer is found in the stomach?

Oblique layer

Which cells secrete hydrocholic acid?

Partiel cells

Which cells secrete pepsinogen?

Cheif cells

Which cells secrete mucus?

Mucous neck cells

Which cells release hormones like gastrin?

Enteroendocrine cells

Does absorption occur in the stomach?

No.

What is the major site of digestion and absorption?

Small intestine

Name the three parts of the small intestine.

Doudenum, jejunum, ileum

Where do bile and pancreatic juice enter the intestine?

Duodenum

What structures increase surface are for absorption?

Pilcae circilares, villi, microvilli

What is the brush border?

Area formed by microvilli that completes digestion

What is a lacteal?

A lymph capillary that absorbs fats

What is the digestive function of the liver?

Produces bile

What is bile used for?

Emulsifying fats

What is bilirubin?

Waste product form the red blood cell and breakdown

What is the function of the gallbladder?

Stores and concentrates bile

What does the pancreas secrete for digestion?

Digestive enzymes (Pancreatic juice)

Where are pancreatic enzymes release?

Duodenum

What are the main functions of the large intestine?

Absorbs water and electrolytes; stores feces

What are the three unique features of the large intestine?

Teniae coli, haustra, epiploic appendages?

Where is water mainly absorbed?

Large intestine

What is the function of the goblet cells in the large intestine?

Secrete mucus to ease passage of the feces

Where does most absorption occur?

Small intestine

How are carbohydrate absorbed?

Active transport into capillaries

How are proteins absorbed?

As amino acids via carrier proteins

How are lipids absorbed?

Via micelles into lacteals

What vitamins are fat-soluable?

A,D,E,K

What vitamins are water soluable?

B and C

What is appendicitis?

Inflammation of the appendix

What are the two types of IBD?

Crohn disease and ulcerative colitis

What causes gallstones?

Crystallized cholesterol forming in bile.