Mammals

Digestive System• Purpose: To break down

food into useable molecules to be carried to cells via blood

A. MouthB. EsophagusC. StomachD. Small IntestinesE. 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

1) Mouth-teeth physical digestion of all food types.

2) Salivary glandsProduce salivaEmpties into mouthUnder the direction of your brain

-how commercials workContains enzyme amylase

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 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. 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