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Unit 16 (Ch. 22) Gas Exchange & Excretion

Unit 16 (Ch. 22) Gas Exchange & Excretion. How do organisms: Obtain oxygen and eliminate carbon dioxide? (or vice versa…in plants?) Maintain osmotic balance? Excrete nitrogenous waste products?. 300. Part 2. Excretion of metabolic waste & Maintenance of Osmotic Balance ch . 22.2.

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Unit 16 (Ch. 22) Gas Exchange & Excretion

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  1. Unit 16 (Ch. 22)Gas Exchange & Excretion How do organisms: Obtain oxygen and eliminate carbon dioxide? (or vice versa…in plants?) Maintain osmotic balance? Excrete nitrogenous waste products? 300 Part 2

  2. Excretion of metabolic waste &Maintenance of Osmotic Balancech. 22.2

  3. Excretion of metabolic waste…is different from the elimination of digestive wastes!

  4. Excretion • What is excretion? • removal of wastes produced from metabolism of nutrients (& other non-useful materials) • CO2 • excess water • nitrogenous waste • All metabolic wastes removed through excretory organs (nephridia, Malpighian tubules, kidneys) • exception = CO2, excreted with water vapor through lungs

  5. Excretion • Why must cellular wastes be removed? • can be toxic • Which life characteristic does excretion relate to? • homeostasis

  6. Nitrogenous Waste • mostly from protein metabolism • & some from nucleic acids • amino groups quickly pick up H • to become ammonia • highly toxic • may be excreted directly or converted to less toxic forms • urea • uric acid

  7. How is the production of urea/uric acid an adaptation to life on land/dry environments? Nitrogenous Wastes • ammonia • excreted by aquatic organisms • urea • excreted in small amount of water •  urine • uric acid • insoluble • excreted as crystals • in arid environments H2O conservation

  8. Importance of H2O: reactions, part of blood, disperse heat Osmotic Balance • concentration of dissolved particles in liquid inside & outside cell is the same (isotonic) • What if the concentrations are different? • hypotonic • cytolysis • hypertonic • plasmolysis • Adaptations for waste removal may also be responsible for maintaining osmotic balance

  9. excretion ammonia is soluble diffuses from (cells) into water osmotic balance naturally in balance no special adaptations needed SALT WATER ORGANISMS

  10. excretion waste diffuses from (cells) into water osmotic balance not naturally in balance (hypotonic environment) Adaptations to help maintain? contractile vacuole ex. Paramecium Fresh Water Organisms Video of Paramecium--Contractile Vacuole

  11. Planaria excretion of wastes & osmotic balance system of excretory canals & flame cells canals branch into excretory ducts open as pores on the surface Fresh Water Organisms

  12. Land Animals • cannot diffuse ammonia • must convert to urea or uric acid • can safely build up in body fluids until excreted • wastes transported by blood or tissue fluid • system excretes N-wastes & is a factor in osmotic balance • H2O conservation emphasized Uric acid Uric acid

  13. LAND ANIMALS: EARTHWORM • ammonia • diffuses through skin • into soil moisture • urea • eliminated through nephridia • filtering organs

  14. LAND ANIMALS: GRASSHOPPER • Malpighian tubules • filter blood • reabsorb water • uric acid enters intestine • excreted thru anus • Why is ammonia converted uric acid (crystals)? • H2O conservation

  15. Habitat? desert Can survive without drinking H2O. How is this possible? gets water from food extremely efficient kidneys reabsorbs almost all water that passes through them excretes very concentrated urine Land Animals: Kangaroo Rat

  16. Which parts of the human body carryout excretion? lungs CO2 & H2O (vapor) skin H2O & salts = sweat urinary system urea, H2O, salts = urine Human Excretion

  17. HUMAN EXCRETION • What are the parts of the urinary system? • kidneys (& associated blood vessels) • main excretory organ • ureters • (urinary) bladder • urethra

  18. HUMAN EXCRETION: THE KIDNEY • main excretory organ • 3 parts • outer part • cortex • inner layer • medulla • inner collecting area • pelvis

  19. 5 STEPS TO HOW KIDNEYS WORK • blood w/ waste brought to kidneys from renal artery • blood is filtered by nephrons (by diffusion) • wastes pass thru ureters to bladder as urine • clean blood sent back to body thru renal vein • bladder stores urine (until passes out of body thru urethra) How Kidneys Work Video 1 million nephrons per kidney!!!

  20. NEPHRON • What is a nephron? • functional unit of the kidney • responsible for filtration of waste from blood • ~1 million nephrons per kidney!!!

  21. nephron consists of: Bowman’s capsule cup-shaped surrounds glomerulus narrows into coiled tubule NEPHRON: STRUCTURE

  22. glomerulus mass of capillaries in center of Bowman’s capsule that forms from branch of renal artery carries unfiltered “waste-filled” blood to nephron another arteriole loops away from glomerulus & divides into capillaries that surround tubule NEPHRON: STRUCTURE

  23. capillaries surround tubule merge to form venules & veins which merge to form renal vein which returns filtered blood back to body NEPHRON: STRUCTURE

  24. PROCESSES IN THE NEPHRON • filtration of blood/ urine production • requires three distinct processes: • glomerular filtration • tubular reabsorption • tubular secretion • excretion of urine

  25. PROCESSES IN THE NEPHRON • 1. filtration • “waste-filled” blood brought to kidney by renal artery • blood pressure forces plasma from blood in glomerulus into Bowman’s capsule of nephron • this liquid =filtrate(water, urea, salts, glucose, amino acids & other dissolved materials) • large proteins & blood cells do not enter

  26. PROCESSES IN THE NEPHRON • 2. tubular reabsorption • filtrate travels through nephron in tubule • needed materials are reabsorbed into surrounding capillaries • ex. most of water, salts, glucose, vitamins, etc. • by active or passive transport • excess materials remain in the collecting duct • water , urea, salts • concentrated fluid = urine tubule.

  27. PROCESSES IN THE NEPHRON • 3. tubular secretion • molecules present in blood in great excess (or natural poisons) may be removed from capillaries & transferred to tubules for excretion • often by active transport • ex. drugs such as antibiotics • “clean” blood sent back to body through renal vein

  28. excretion urine (urea, excess salt, small amount of water) leaves nephron & passes from collecting duct to renal pelvis leaves kidney via ureters to bladder where stored until once filled & urine is excreted through urethra (urination) PROCESSES IN THE NEPHRON How Kidneys Work Video

  29. PROCESSES IN THE NEPHRON

  30. PROCESSES IN THE NEPHRON

  31. PROCESSES IN THE NEPHRON

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