Download Digestive System - Mercer Island School District

Digestive System
Adara, Bianca, Caroline, & Nathaniel
DeBroux, Period 7
Digestion:
- The Process by which the large complex molecule in food are broken down
into smaller molecules that can be used in the body.
Digestive System:
-
A collection of organs that breaks down food into energy that can be
used in cells.
Primary Function:
-
The function is digestion and absorption. It is the breakdown of food into
small molecules, which are absorbed into the body.
Major Organs:
- Mouth:
- Pharynx
- Esophagus
- Liver
- Stomach
- Small Intestine
- Large Intestine
- Gallbladder
Homeostasis
- The Digestive System helps the body maintain Homeostasis because it all
depends on the essential nutrients that come in from the food you eat. These
nutrients help repair the structure of the Digestive System and replenish it
when needed.
Other Systems Related:
Circulatory System:
- The organs in the digestive system need the circulatory system to continue to
digest food.
- It needs the blood that the circulatory distributes for its nutrients as well as to
have nutrients spread, so that the body can function.
Respiratory System:
-
All the other systems have to work together as well, without the intake of
oxygen and exhalation of carbon dioxide, the function of the digestive would
stop.
Diseases:
Gastroesophageal Reflux Disease (GERD)
- Weakness of the valve between esophagus and stomach allows acid to reflux
into the esophagus and irritate the lining
- Results in chest pain (heartburn)
Jaundice
- Yellowing of skin and eyes from a backup of bile from the blood into body
tissues
- Caused by blockage of ducts draining bile from the liver into intestines or
Pathway of Food
Step 1) Mouth/Pharynx- Mechanical breakdown of food by chewing and chemical
breakdown through saliva
Step 2) Esophagus- Food moves towards the stomach by peristaltic movements
Step 3) Small intestines- Where the food is broken down and also the digestion of
starches and salt
Step 4) Appendix- Dead end of cecum, some bacterial action, and produces
vitamin K and continues to digest
Step 5) Rectum- Feces (undigested material and bacteria)
Step 6) Anus- Waste leaves the body and digestive system
Major Enzymes
Amylase & Mycozyme - Aids breakdown of starches
Lipase - Increases the breakdown of fats (lipids)
Protease & Pepsin - Helps the breakdown of protein
Pancreatin - The various pancreatic enzymes
Bile - Emulsifies fats preparing them for further digestion and absorption in the
small intestine
Cellulase - an enzyme that breaks down cellulose
Intestinal Villi
- Villi are small, finger-like projections on the
epithelial lining of the small intestine’s walls.
- Each villus has many microvilli projecting from the
enterocytes collectively form the brush border.
- Much smaller than the circular folds in the
intestine
- Increase surface area of the intestinal walls
making a greater area for absorption