Diet, Disease, and Digestion

Eva Murdoch, PhDAssistant Professor, Anatomy and PhysiologyDepartment of Natural SciencesJoliet Junior College

Organs of the Digestive System

1. Gastrointestinal tract (GI):

mouth, esophagus, stomach,

small & large intestine

2. Accessory organs: salivary

glands, liver, gall bladder,

pancreas

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

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

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

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

Nutrient Molecules

1. 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

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

3. Proteins– Functions: enzymes, hormones, muscle, last resort

for energy 4 Cal / 1 gram– Found in: meat, nuts, beans, dairy, eggs

Diet Pyramid

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

• Stomach ulcer– 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

• Colon polyp– Cause: irritable bowl syndrome (IBS)

history– Pathology: abnormal growth, rectal

bleeding– Treatment: surgery

• 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

• 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

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