Transcript Digestive System

Digestive
System
Digestive System
• Purpose:
– To break down food into
useable molecules to be
carried to the
cells via our
blood
Digestive Pathway
(Path the food travels)
A.
B.
C.
D.
E.
Mouth
Esophagus
Stomach
Small Intestines
Large Intestines
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
Digestive Pathway…..where
food travels through.
1) Mouth-teeth physical digestion
of all food types.
2) Salivary glands
Produce saliva
Empties into mouth
Under the direction of your brain
-how commercials work
Produces the enzyme amylase
Responsible for the chemical
digestion of carbohydrates
3) Pharynx
Back of throat area
Common passage for
-food and air
No 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.
2.
3.
4.
5.
6.
7.
Ingest
Chew 10 to 30 times
Swallow 4 to 8 seconds
Churn 2 to 4 hours
Absorb 3 to 5 hours
Compact 10 hours to several days!
Eliminate
The end………….
Digestive Problems
• Acid reflux
• Ulcer
Gall stones
Made up of bile salts and cholesterol
Appendicitis
• Diverticulitis:
• Hemorrhoids