Digestive System
Dec 31, 2015
Digestive System
Digestive System• Purpose:
– To break down food into useable molecules to be carried to the
cells via our blood
A. MouthB. EsophagusC. StomachD. Small IntestinesE. Large Intestines
Digestive Pathway(Path the food travels)
3 types of nutrients: Carbohydrates:
-provide quick energy-must be digested into their
simplest form/simple sugar molecule
-bun Fats/lipids:
-long term energy-must be digested -cheese and in red meat
Protein:-build and maintain our cells and tissues-must be digested down into individual amino acids-cheese and red meat
1) Mouth-teeth physical digestion of all food types.
2) Salivary glandsProduce salivaEmpties into mouthUnder the direction of your brain
-how commercials workProduces the enzyme amylase
Responsible for the chemical digestion of carbohydrates
Digestive Pathway…..where food travels through.
3) PharynxBack of throat areaCommon passage for
-food and airNo digestion occurs
Digestive System
• 4) Esophagus– Passageway for food from mouth to stomach– No digestion– peristalsis: Wave-like motion that pushes food
to stomach animation• 5) Cardiac Sphincter
– End of esophagus, beginning of stomach– Ring of muscle – Keeps food moving in 1 direction– What is “heart burn”?
if food moves back into esophagus from sphincter. Contains acid from stomach
Digestive System
• 6) Stomach– Muscular sac which
digests proteins– Physical digestion in form
of churning– Chemical digestion in
form of HCl, gastrin + pepsin to break down proteins
– Special lining to protect from acid; “sore” in this lining can lead to an ulcer
– Chyme- undigested food+enzyme+acid mixture.
Digestive System• 7) Pyloric Sphincter
– Ring of muscle which keeps food moving from stomach to sm. intestine
• 8) Small Intestine– ~20-21 ft. long– 3 sections– Duodenum: 1st 10 inches,
carries chyme to jejunum, is were all enzymes from pancreas and gall bladder empty into
– Jejunum: 8 feet, carbs, proteins, lipids digestion; were food molecules are absorbed into blood
– Ileum: 13 feet, takes undigested material to large intestine
– Has villi
Villi in Small Intestine-Villi increases surface area of small intestines so more food can be absorbed into the blood faster.
Digestive System• 9. Large Intestine/colon
– larger in diameter– 3 ft. long- removes excess water
for undigested matter– too much water
absorbed=constipation– too little water
absorbed=diarrhea
• 10. Rectum & Anus– holds solid waste until
expelled (rectum)– exit (anus)
animation
Organs part of the digestive system BUT not part of the
digestive pathway.
1. Appendix• Appendix-
– No apparent function in humans– In other mammals, it helps to
digest plant materials/cellulose
– animation
• 2. Liver:– Largest internal organ– Filters ammonia out of blood and converts it into urea– Makes bile
• 3. Gall bladder – Stores bile: for the digestion of lipids, empties into sm. Intestines via common bile duct.
• 4. Pancreas- • makes and delivers the following to small intestines:
– pancreatic amylase- carbs – lipase-lipids – trypsin- proteins– sends these enzymes to small intestine through the pancretic duct.– Sodium bicarbonate
• -is a base, neutralizes HCl so it does not damage small intestines.
To Digest…
1. Ingest
2. Chew 10 to 30 times
3. Swallow 4 to 8 seconds
4. Churn 2 to 4 hours
5. Absorb 3 to 5 hours
6. Compact 10 hours to several days!
7. Eliminate
The end………….
Digestive Problems
• Acid reflux
• Ulcer
Gall stonesMade up of bile salts and cholesterol
Appendicitis
• Diverticulitis:
• Hemorrhoids