1. Ch 8 Digestive System
Structures

2. Digestive System AKA alimentary canal Aliment means to nourish
-ary means pertaining to
Responsible for
Intake & digestion of food
Absorption of nutrients from digested food
Elimination of solid waste products

3. Major Structures Oral Cavity Pharynx Esophagus Stomach Small intestine
Large intestine
Rectum
Anus
Accessory organs
Liver
Gallbladder
pancreas

4. Gastrointestinal tract
Divided into two sections
Upper GI tract
Mouth, esophagus, & stomach
Lower GI tract
Small intestine, large intestine, rectum, & anus
Sometimes referred to as the bowels

5. Oral Cavity Lips aka labia Palate Hard palate -Soft palate
Rugae -uvula
Tongue
Papillae aka taste buds

6. Oral Cavity
Teeth
Dentition refers to the natural teeth arranged in the
upper (maxillary) and lower (mandibular) arches.
Primary or deciduous dentition
Permanent dentition
Edentulous means without teeth
Periodontium – bone and soft tissues that surround teeth
Gingiva aka gums, specialized mucous membranes
That surrounds the teeth
Salivary glands secrete saliva that moistens food, begins the
digestive process, and cleanses the mouth
3 pairs; parotid, sublingual, & submandibular

7. Pharynx Aka throat Common passageway for both respiration & digestion
What structure closes off and prevents food from entering
the trachea during swallowing?

8. Esophagus Sometimes called the gullet
A collapsible tube that leads from the pharynx to the
Stomach
Has a ringlike muscle at the end that controls the flow between the esophagus and the stomach called the lower esophageal sphincter or cardiac sphincter.

9. Stomach
A saclike organ made of the fundus (upper, rounded part), the body(main part), and the antrum (lower part)
Has folds in the mucosa lining called Rugae. These folds have glands that make the gastric juices.
The pylorus is the narrow passage that connects the stomach with the small intestine
Pyloric sphincter is the muscle ring that controls the flow from the stomach to the duodenum of the small intestine.

11. Small Intestine Has 3 parts Duodenum, beginning Jejunum, middle
Ileum, last portion
Ileocecal sphincter controls the flow from the ileum of the small intestine into the cecum of the large intestine
Has little hairlike or fingerlike projections called villi that line the walls. These absorb fats and fat soluble vitamins

12. Large Intestine Major parts;
Cecum is a pouchlike structure at the beginning of the large intestine. The vermiform appendix hangs from the lower portion.
Colon
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum is the third major division
Anus is the lower opening of the digestive tract. Flow of waste controlled by two anal sphincter muscles.

13. Accessory Digestive Organs
Liver
Found in the RUQ
Removes excess glucose from bloodstream & stores it as glycogen
Destroys old erythrocytes
Bilirubin is a pigment produced from the destruction of hemoglobin
Makes & secretes bile
Digestive juice that has enzymes that break down fat

14. Accessory Digestive Organs
Gallbladder
Pear shaped sac located inferior the liver
Stores and concentrates bile for later use
Pancreas
Feather shaped organ located posterior to the stomach
Has digestive and endocrine functions. We will discuss the endocrine function in a different chapter.
Synthesizes and secretes pancreatic juices. These juices help the body process protein, carbs, & fats, as well as helping to neutralize stomach acids.

15. Digestion

16. Digestion
The process by which foods are broken down into nutrient form the body can use.
Enzymes are responsible for the chemical changes that break foods down into simpler forms of nutrients the body can use
A nutrient is a substance, usually from food, that is necessary for normal functioning of the body

17. Metabolism All the processes involved in the body’s use of nutrients.
Anabolism, the building up of body cells or substances
Catabolism, the breaking down of body cells or substances

18. Miscellaneous Terms Mastication aka chewing
Peristalsis - wavelike contractions of the smooth muscles
Chyme – semifluid mass of partly digested food
Emulsification – digestion of fats by pancreatic juices
Feces or stools
Defecation or bowel movement
Flatulence, flatus, or gas
Borborygmus is the rumbling noise created by the movement of gas in the intestine