Unit 8: Digestion/Excretion

1. Unit 8: Digestion/Excretion • Guided Note Packet • Science in Our Lives II 1

2. What is “Digestion” and “Excretion”? Digestion: breakdown of food (organic molecules) into a form CELLS can use! - includes the elimination of solid waste materials Excretion: removal of LIQUID and GASEOUS waste from body - includes urine, heat, water, and carbon dioxide 2

3. TWO WAYS TO OBTAIN FOOD 1. AUTOTROPHIC: means an organism can make its own food using photosynthesis Ex. Plants, algae Photosynthesis - chemical rxn where plants use the sun’s energy to make food 3

4. Photosynthesis Chemical Reaction Plants only Happens in the chloroplast CO2 + H2O --> C6H12O6 + H2O + O2 Carbon dioxide + water glucose +water+ oxygen *Remember: Photosynthesis makes glucose which is food for the plant; water and oxygen are waste products 4

5. Leaf Parts (Food Factory) Remember, this is where PHOTOSYNTHESIS takes place; in the chloroplast of the leaf! Cuticle- wax layer to protect against water loss Palisade layer- layer w/most chloroplasts; most photosynthesis takes place here Stomates- pores (openings) in bottom of leaf that allow O2 and CO2 in and out; regulated by guard cells Guard cells- cells that swell or deflate to open/close stomates 5

6. Leaf Parts (Food Factory) cont. Chloroplasts- organelles that contain chlorophyll Spongy layer- air spaces in the leaf for CO2 and O2 exchange Vein- tubes that contain xylem and phloem for transport of water and food in plant 6

7. Leaf Diagram 7

8. What affects Photosynthesis? As CO2 ____in plants, photosynthesis ______ As light ______ in plants, photosynthesis ________As temperature ______ in plants, photosynthesis _______ 8

9. Second Way to Obtain Food 2. Heterotrophic: organism must get food because it cannot make its own Ex. Humans, dogs, horses 1) Ingestion - taking in of food 2) Digestion - breaking food down into usable form for cells 3) Egestion - removing undigested food 9

10. Types of Digestion Mechanical digestion - chewing, increasing surface area; takes place in mouth & stomach; breakdown into smaller pieces Chemical digestion - use of enzymes to chemically change food into a form cells can use; takes place in mouth, stomach, and small intestine 10

11. Chemical Digestion - Enzymes Enzyme: protein type structure that increases the rate of a reaction Each enzyme is SPECIFIC! It has a unique SHAPE that only works with a particular type of nutrient! Protease only works with Proteins! Lipase only works with Lipids! Maltase only works with Carbohydrates! 11

12. Enzyme-Substrate Complex Notice that the two fit together because their SHAPES match. Enzymes that do not match the nutrient they break down Do Not Fit Together! 12

13. Parts of the Human Digestive System Aka Alimentary Canal Function Ingestion/digestion; chemical-saliva (starch); mechanical-chewing Tube between mouth and stomach (peristalsis happens here) Flap of skin that prevents food from entering the trachea(windpipe) Part Mouth Esophagus Epiglottis Peristalsis- muscle movements that keep food moving through the alimentary canal 13

14. Parts of the Digestive System continued… Stomach Pancreas Liver Gall Bladder Muscular sac for digestion; mechanical-moves food; chemical-HCl, pepsin, others Chemicals found in the stomach include: HCl-acid; protease breakdown protein; Chyme: “soup” of chemicals in the stomach Produces digestive enzymes protease, lipase, maltase; sent through a duct into the small intestine; food does not pass through this! Produces bile for emulsification(breakdown) of fats; food does not pass through this! Stores bile 14

15. Parts of the Digestive System continued… Small intestine Large intestine Anus Absorption of nutrients; longer & narrower than large intestine; where most digestion occursVilli: small finger-like tissue on inside of small intestine that increases how much nutrients can be absorbed Absorbs water out of undigested food; regulates water in body Location where waste is egested from the body 15

16. The Digestive System 16

17. Nutrient Breakdown Review broken down by digestion into Complex molecule Simple Molecules broken down by digestion into Proteins Amino acids broken down by digestion into Simple Sugars Carbohydrates broken down by digestion into Fats (lipids) Fatty Acids and Glycerol 17

18. Disruptions in Homeostasis Involving Digestion Ulcer - sore in the stomach Tooth decay - bacterial infection in the mouth Anorexia - disease where one refuses to eat; body begins to starve to death 4) Bulimia - when one eats and throws up to avoid gaining weight; also the excessive use of laxatives 18

19. Disruptions in Homeostasis Involving Digestion 5) Indigestion - an excessive amount of acid in the stomach 6) Diarrhea - when not enough water is absorbed by the large intestine 7) Constipation - when too much water is absorbed by the large intestine and feces has difficulty movingHow does the body get rid of LIQUID and GASEOUS wastes?EXCRETION 19

20. Examples of Wastes That MUST Be Excreted From The Body Carbon dioxide (gas): comes from aerobic respiration Water (liquid and gas): comes from aerobic respiration and synthesis Urea and salt (liquid): comes from breakdown of protein 20

21. Why Get Rid Of These Waste Products? Toxic: poisonous; may cause illness or death High levels of any substance is _________ to the body; we must either ____________ it or _________ it down. Main Human ORGANS OF EXCRETION include: kidneys (renal = kidney) lungs skin liver 21

22. Parts of the Human Excretory System Function CO2 and H2O are exhaled here Makes urea from broken down protein; absorbs nutrients in the blood; even alcohol Primary excretory organ; filters urea out of the blood using nephrons (renal = kidney)nephrons:tiny units in the kidney that clean urea, salt, and waste from blood Removes salt and urea and water from the body; regulates body temp Part Lungs Liver Kidney Skin 22

23. THE HUMAN URINARY SYSTEM (A DIVISION OF THE EXCRETORY SYSTEM) PART FUNCTION Kidney filters blood to make urine; renal means “kidney” Ureter tube that carries urine from kidney to bladder Bladder sac that stores urine Sphincter muscle controls release of urine Urethra location where urine exits the body 23

24. The Urinary System 24

25. Dialysis When your kidneys have a disruption in homeostasis (balance), it may mean they are unable to filter the blood. Someone who’s kidneys do not work properly usually has to go through DIALYSIS. Dialysis: medical method of filtering blood using a machine 25

26. THE SKIN (Part of the Excretory System) Skin is the ____________organ in the body. It weighs about ______pounds.The main purpose of the skin is to regulate _________________. Three layers of the skin: 1. Epidermis: __________ layer of skin and contains _________ which are small openings in the top of the skin. This layer is replaced every _______ days or so. largest 7-8 body temperature top (outer) pores 28 Perspiration (sweat) is what helps cool the body 26

27. THE SKIN (Part of the Excretory System) 2. Dermis: ______ layer of skin and contains _________ which is a pigment that gives skin color. It also contains __________ and _________________. 3. Subcutaneous: ______ layer of skin that contains _________. It provides ________ for our muscles and attaches the skin to the rest of the _______________. melanin middle nerves blood vessels deepest fat protection body 27

28. Skin Diagram Pore Epidermis Dermis Subcutaneous layer 28