Digestive System

Food changed to energy (ATP) through digestion & cell respiration Function – to break food down into simpler molecules that can be absorbed & used by cells Food changed to energy (ATP) through digestion & cell respiration Cellular respiration: Glucose (simple sugar) + Oxygen  ATP (energy) Takes place in the mitochondria of the cell

Nutrition Study of food & it’s effect Calories 1 Cal = 1000 calories or 1kc 1 calorie = amount of energy needed to raise temp. of 1 gram of water by 1 degree Celsius

Nutrients are need by the body for growth, repair, and maintenance Water Carbohydrates c. Lipids (Fats) e. Vitamins d. Proteins f. Minerals

a. Water – our body is made of appr. 70% water, many cell reactions b. Carbohydrates – main energy source Starches are broken down into simple sugars to make ATP Lipids (Fats) – glycerol & fatty acids Used to make cell membranes & hormones Saturated fats are solid at RT Unsat. Fats are liquids at RT Diet high in fat leads to high BP, heart disease, obesity & diabetes

Proteins- composed of AA Used for growth Repair Hormones & oxygen transport 8 essential AA must be obtained from diet Vitamins – organic molecules that regulate body processes Vitamin D- bone health Vitamin A – night blindness

Minerals - inorganic molecules needed by body Calcium- bones & teeth Iron - hemoglobin Sodium nerve & Potassium impulse transmission

Food Pyramid

Organs of Digestive System: Mouth  Pharynx  Esophagus  Stomach  Small Intestine  Large Intestine Food & air can pass through the pharynx Peristalsis – muscle contractions in the esophagus that squeeze food to the stomach Absorption of nutrients occurs in the small intestine Water is removed from undigested material in the large intestine

Organs of Digestive System: (con’t) Accessory Organs: Liver – produces bile that helps break down fats Gall Bladder – stores the bile Pancreas – Produces hormones to regulate blood sugar Produces enzymes (insulin) to break down nutrients Produces a base that neutralizes stomach acid

Functions of Digestive System: Mechanical digestion - chewing, mixing in stomach Chemical digestion by enzymes, breaking large food molecules into smaller parts Example: Amylase - from salivary glands; breaks down carbohydrates Hydrochloric acid and pepsin - digests protein in stomach Bile - from liver that dissolves fat

Absorption of nutrient molecules into the bloodstream occurs in the small intestine Villi are small finger-like projections that increase the surface area of small intestine

Disorders Stomach ulcers Diarrhea Constipation

Excretory System

General Information: Function is to remove wastes from the blood & excrete them from the body Important in maintaining homeostasis

Organs of the Excretory System: Skin, liver, and lungs – remove wastes from the body Kidneys – the main organ: Remove wastes produced by the metabolism of proteins in the cells Purify the blood Adjust the pH Maintain the water balance of the blood (retain/eliminate water)

Organs of the Excretory System: Nephron: Functional unit of the kidney Filters blood and many materials are reabsorbed by veins Urine is collected and passes out through the Loop of Henle where water is reabsorbed

Kidney function is controlled by: Regulatory hormones Water and salt concentrations in the blood, which is influenced by what you eat and drink

Kidney Nephron Cortex Medulla Renal artery Renal vein Ureter To the bladder Bowman’s capsule Glomerulus Capillaries Collecting duct To the ureter Loop of Henle Artery Vein

Kidney Stones: