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Human Anatomy & Physiology DIGESTIVE & EXCRETORY SYSTEMS Biology – Chapter 38 1.

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Presentation on theme: "Human Anatomy & Physiology DIGESTIVE & EXCRETORY SYSTEMS Biology – Chapter 38 1."— Presentation transcript:

1 Human Anatomy & Physiology DIGESTIVE & EXCRETORY SYSTEMS Biology – Chapter 38 1

2 Primary Function 2 Convert foods into simpler molecules that the body can absorb and be used by cells (Click)

3 What & why do we need to eat? 3 Nutrients – supply energy and raw materials for body to perform life functions Water – all chemical reactions in your body require water Carbohydrates – the main source of energy Fats – helps produce membranes, myelin, some hormones Proteins – raw materials for growth & repair, enzymes Vitamins – organic molecules that help regulate body processes Minerals – inorganic nutrients needed for bodily functions

4 Anatomy of Digestion 4 Digestive System Primary Organs: Mouth, Pharynx, esophagus, stomach, small intestine, large intestine Accessory organs (add secretions to aid digestion): salivary glands, pancreas, liver

5 Mouth & Salivary Glands 5 Primary function: Break down, moisten food & start chemical digestion (mechanical and chemical digestion) Teeth – mechanical digestion Salivary glands – produce amylase to start chemical digestion (Click)

6 Pathways in the Mouth 6 Back of mouth (pharynx) leads to TWO tubes: Esophagus (empties into stomach) Trachea (leads to lungs) DONT want food to clog trachea! Direction controller = epiglottis

7 The Esophagus 7 Tube connecting the mouth and the stomach Tongue and throat push chewed, moistened food (bolus) past the epiglottis into the esophagus Bolus is moved through esophagus by involuntary muscular contractions (peristalsis) (Click)

8 The Stomach 8 The bolus is mechanically (churning) and chemically digested in the stomach Chemical digestion: HCl Pepsin Produces Chyme Pushed through pyloric valve to small intestine

9 Small Intestine 9 Anatomy: 3 parts -Duodenum -Jejunum -Ileum -Villi Function: -Location where most food is digested & absorbed Accessory organs: -Pancreatic enzymes (Starch, protein, fat) -Liver enzymes (Bile-fat digestion, stored in gall bladder)

10 Villi 10 Villi greatly increase small intestine surface area for more effective absorption (can cover an area as large as a tennis court) Undigested substances (cellulose, water, etc.) leave small intestine & move to large intestine

11 Large Intestine 11 Anatomy: -Ascending colon -Appendix -Transverse colon -Descending colon Primary Function: -Reabsorb water Waste material passed to rectum (storage, bacterial colonies produce organic nutrients) Excess waste released through anus

12 Digestion Summary 12

13 Excretory System 13 Anatomy: Skin Lungs Liver Kidneys Primary functions: Maintain homeostasis Remove toxic chemicals

14 Liver 14 Converts excess amino acids (from protein digestion) into useful nutrients, producing nitrogen waste products (urea) Passed on to kidneys

15 Kidneys 15 Two kidneys in lower back Filter blood to remove waste products Ureters connect to urinary bladder - removed through urethra Kidney Anatomy: -Nephron -Filters out toxic waste -Reabsorbs water, essential nutrients

16 Dialysis 16

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