1. Diet, Disease, and Digestion
Eva Murdoch, PhD
Assistant Professor, Anatomy and Physiology
Department of Natural Sciences
Joliet Junior College

2. Organs of the Digestive System
Gastrointestinal tract (GI): mouth, esophagus, stomach, small & large intestine
Accessory organs: salivary glands, liver, gall bladder, pancreas

3. Functions of the GI tract and Accessory Organs
GI tract: continuous muscular tube which passes, digests, and absorbs food molecules, and eliminates the indigestible residue
Accessory organs: release digestive juices into the muscular tubule, and aid in the breakdown of nutrients

4. Digestive System
Living organisms must obtain nutrients from their environment to sustain life
The digestive system breaks down large nutrient molecules to small nutrient molecules that all body cells can then use to:
Synthesize ATP (cell’s energy supply)
Perform structural maintenance, repair and support growth

5. Digesting and Absorbing Nutrients
Salivary glands, pancreas and liver help with the digestion of large food molecules to small molecules by secreting enzymes
Digestion Absorption
Carbs  monosacchrides blood
Fats  fatty acids blood
Proteins  amino acids blood

6. Cell Metabolism All chemical reactions that occur in a cell
Synthesis of ATP
Synthesis of new organic molecules, and other cell functions that require ATP

7. Nutrient Molecules Carbohydrates / Sugars
Function: short-term energy supply 4 Cal / 1 gram (calories are a unit of energy)
Found in: grains (wheat, rice, oats, corn), fruits, veggies

8. Lipids / Fats
Function: energy reserve, padding, insulation 9 Cal / 1 gram
Found in: nuts, red meat, milk, eggs, butter

9. Proteins
Functions: enzymes, hormones, muscle, last resort for energy 4 Cal / 1 gram
Found in: meat, nuts, beans, dairy, eggs

10. Diet Pyramid

12. Disease GERD – gastro-esophageal (acid) reflux disease
Cause: stomach acid in the esophagus, due to weak esophageal sphincter
Pathology: erosion of esophageal tissue  pain
Treatment: largely preventable by changes in lifestyle, medication, surgery

13. Stomach ulcer Stomach cancer
Cause: inflammation due to H. pylori infection
Pathology: bleeding in stomach
Treatment: antiacid, antibiotics, anti-inflammatories
Stomach cancer
Cause: H. pylori infection, genetics
Pathology: abnormal growth (tumor) in stomach tissue
Treatment: surgery, chemotherapy

14. Colon polyp Cause: irritable bowl syndrome (IBS) history
Pathology: abnormal growth, rectal bleeding
Treatment: surgery

15. Colon Cancer (3rd most commonly diagnosed cancer)
Cause: genetic, polyps, diet, smoking, excessive drinking
Pathology: uncontrolled cell growth in colon, rectal bleeding
Treatment: surgery, chemotherapy, radiation therapy

16. Liver cirrhosis Cause: chronic alcoholism and hepatitis C infection
Pathology: liver cells (hepatocytes) are replaced by fibroblasts (cells found in tendons, can’t perform liver functions)
Treatment: liver transplant

17. Pancreatic Cancer Cause: genetics, age, smoking, diet, diabetes
Pathology: mutations in the pancreatic cell and tumor growth
Treatment: surgery, chemotherapy