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Human Anatomy & Physiology DIGESTIVE & EXCRETORY SYSTEMS

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Presentation on theme: "Human Anatomy & Physiology DIGESTIVE & EXCRETORY SYSTEMS"— Presentation transcript:

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

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

3 What & why do we need to eat?
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 When you eat foods—such as bread, meat, and vegetables—they are not in a form that the body can use as nourishment. Food and drink must be changed into smaller molecules of nutrients before they can be absorbed into the blood and carried to cells throughout the body. Digestion is the process by which food and drink are broken down into their smallest parts so the body can use them to build and nourish cells and to provide energy.

4 Anatomy of Digestion Digestive System Primary Organs: Mouth, Pharynx,
esophagus, stomach, small intestine, large intestine Accessory organs (add secretions to aid digestion): salivary glands, pancreas, liver Two main parts to digestive system: The primary organs & the accessory organs that add secretions to aid digestion

5 Mouth & Salivary Glands
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 Back of mouth (pharynx) leads to TWO tubes:
Esophagus (empties into stomach) Trachea (leads to lungs) DON’T want food to clog trachea! Direction controller = epiglottis

7 The Esophagus 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 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 Anatomy: 3 parts Duodenum Jejunum Ileum Villi
Function: Location where most food is digested & absorbed Bile acts as a “detergent”, helping to break down fats and allow better absorption into the small intestine Accessory organs: Pancreatic enzymes (Starch, protein, fat) Liver enzymes (Bile-fat digestion, stored in gall bladder)

10 Villi 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 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

13 Excretory System Primary functions: Maintain homeostasis
Remove toxic chemicals Anatomy: Skin Lungs Liver Kidneys Know how each organ functions as an excretory organ

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

15 Kidneys 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 If kidneys fail, a dialysis machine is required to externally maintain blood chemistry homeostasis

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