digestionnotes

We can get an idea of how much of each nutrient to eat by referring to the Food Guide Pyramid.

Food Guide Pyramid: model for a healthy diet. Shows # of servings.

Ways to Eat Healthy

1. Eat a variety of food

2. Maintain healthy weight

3. Don’t eat a lot of fat/cholesterol

4. Plenty of veggies, fruit, grain

5. Sugar in moderation

6. Salt and sodium in moderation

Fiber: aides in digestion, pushes food through digestive tract Sources: veggies, fruit, grain

Body Mass Index Calculation:

1.  Weight (in pounds)/height (in inches) 2 X 704.5 = BMI

Digestion

This is our small intestine. It is 6 meters long!!!

Digestion: breakdown of food into simplest compounds,

1. Mechanical: food is crushed, broken into small pieces ex: mouth chews

2. Chemical: food hydrolyzed complex to simple ex: proteins to amino acids

Alimentary Canal: (Gastrointestinal tract)- tube within a tube

Accessory Organs: secrete enzymes into alimentary canal
 a) salivary glands

b) Liver

c) Pancreas

Label Digestive Tract Diagram

1. Mouth

Mechanical- teeth chew/grind food

Saliva- moisten, sofien food

Chemical- salivary amylase (starchà maltose disaccharide)

2. Epiglottis

-tissue covering larynx

-prevent food from going into lungs

Where would food go if the epiglottis wasn’t there?

-trachea, we cough

3. Esophagus

Peristalsis- muscles contract to move food from mouth-> stomach show balloon pushing beads through

Valve- sphincter prevent acid from coming up

4. Stomach

Mechanical- contract muscles to breakdown food

Mucous secreted (lines stomach)- prevent from acid

Chemical- gastric juice (HCI) from walls (unfolds proteins)

Pepsin (enzyme)- large proteins-> polypeptides (smaller proteins)

chyme: a soupy mixture of food + HC1 + enzymes

hormone: gastrin-regulates HC1 production, pH more than 1.5, produce

HC1

5. Small intestine -coiled tube (6 m long)

Mechanical- bile (liver, stored in gallbladder)

Emulsification: break fats/oils into little droplets chemical-

a) pancreatic juice (pancrease)

protease- digest proteins

amylase- digest carbs

lipase- digest lipids (fatty acids and glycerol) contains sodium bicarbonate- neutralize acid

b) intestinal juice (intestine)

peptidase- digest proteins to amino acids

maltase- maltose-) glucose

villi(fingerlike projections): absorb amino acids, glucose, fatty acids, glycerol.

Lactéals: fatty acids and glycerol absorbed through lacteals to lymphatic system

Increase surface area

99% water absorbed

nutrients go to liver

6. Large intestine

- no digestion

- reabsorb % water

- absorb vitamins from bacteria (K, B)

- elimination- remove undigested/indigestible material (cellulose, bacteria)

stool: stored in rectum, out anus

Problems, Disorders

1. Ulcer

-caused by bacteria H. pylon

- mucous breaksdown

-wall of stomach digested with acid

treatment: antibiotics, no spicy food, surgery

2. appendicitis

-infected, inflamed appendix treatment: have removed

3. diarrhea

- too little water reabsorbed

4. constipation

-too much water reabsorbed

Anorexia and Bulemia dittos