Transcript Mammals

Mammals
Digestive System
• Purpose: To break down
food into useable molecules
to be carried to cells via
blood
A.
B.
C.
D.
E.
Mouth
Esophagus
Stomach
Small Intestines
Large Intestines
3 types of nutrients:
Carbohydrates:
-provide quick energy
-bun
Fats/lipids:
-long term energy
-cheese and in red meat
Protein:
-build and maintain our
cells and tissues
-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
Contains enzyme amylase
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 in form of HCl,
gastrin + pepsin to break
down proteins
– Special lining to protect
from acid; can lead to
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. Caecum/Appendix
• Caecum-pig
– “dead-end”
– Helps digest plant material
• Appendix-humans
– No apparent function
– animation
Rumen: 1st part of a four
chambered stomach
• Sheep, cows: herbivores
• Regurgitate-cud
• 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
• 4. Pancreas• makes and delivers the
following to small intestines:
– pancreatic amylase- carbs
– lipase-lipids
– trypsin- proteins
– sends these enzymes to small intestine
– Sodium bicarbinate
• -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