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DOR: Digestive System

DOR: Digestive System . ___________ is the process of smooth esophageal muscles contracting to move food down into the stomach. Name the acid located in the stomach. __________ are located in the small intestine and contain capillaries for nutrient absorption.

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DOR: Digestive System

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  1. DOR: Digestive System • ___________ is the process of smooth esophageal muscles contracting to move food down into the stomach. • Name the acid located in the stomach. • __________ are located in the small intestine and contain capillaries for nutrient absorption. • What is the main function of the large intestine? • Name the accessory organ that stores bile.

  2. Respiratory System Chapter 35

  3. Why do we need respiration???

  4. Gas-exchange, simple animals • Diffusion • Presence of capillaries help • Animal’s surface becomes important, huge surface area to allow for gas exchange • Oxygen, transport to mitochondria

  5. Gas exchange, aquatic animals • More energy spent with respiration • Possess large surface area (ex. Cnidarians, flatworms) • Invertebrates/vertebrates—gills • contain vascular/blood system • Divided growths from surface/pharynx

  6. Gills • Molluscas: gills located in mantle where water goes through • Fish—mouth and opercula (gill covers) put in a combined effort • Countercurrent exchange utilized—blood always surrounded by water with high oxygen content, prevents equilibrium

  7. Countercurrent Exchange- blood & water flow in opposite directions

  8. Countercurrent Exchange (Aquatic Animals) • Countercurrent exchange allows for the efficient transfer of oxygen to the blood • As blood flows through the capillary, it becomes more and more loaded with oxygen • Steep concentration gradient allows for efficient uptake of oxygen

  9. Insect Tracheae • Open circulation system so this transport not well-developed • Tracheae • Air tubes throughout insect, transport O2 to cells • Branching systems (small tubes—tracheoles) close to cells to ensure O2 transport/CO2 removal • Air sacs • Located at wings, legs, abdomen • Help circulate air and pass through air tubes **Insects can contract and relax air sacs at muscles to circulate air---similar to human lungs

  10. Human Lungs • Located within thoracic cavity • Air filtered as it moves into lungs • Hairs/cilia line respiratory tract to “sweep” debris out and mucus traps particles • Branching: Trachea---bronchi----bronchioles----alveoli • Alveoli— • take up most of the surface area, • surrounded by capillaries to facilitate gas exchange between lungs and blood

  11. Human Respiratory System • Air enters the lungs by a system of branching ducts • Nostrils • Pharynx • Larynx • Trachea (w/ cilia) • 2 bronchi • Bronchioles • Alveoli

  12. Human Respiratory System

  13. Mechanism of Breathing • Negative pressure— • Used to get air in lungs • Positive pressure forces air out • Ex. Birds, mammals, reptiles • Positive pressure— • Air is forced into the lungs • Ex. Amphibians

  14. Mechanism (cont.) • Inspiration— • Air movement INTO lungs • Expiration— • Air movement OUT of the lungs • Other structures • Diaphragm—horizontal muscle separating thoracic cavity and abdominal cavity • Intercostal muscles—aids in inspiration, muscles along the rib cage.

  15. Inspiration • Diaphragm moves down • Rib cage moves • Thoracic cavity expands to allow air to move in • Pressure decreased in lungs, air flows in. • Active phase, intercostal muscles contract

  16. Inspiration

  17. Expiration • Diaphragm relaxation, returns to location • Passive phase, no contractions • Air moves OUT of the lungs--- pressure increases to force air out !

  18. Expiration

  19. Tidal ventilation mechanism • Most vertebrates, not birds • Air passes through the same path going in OR out • Some air does not completely leave the lungs, air mixing occurs—water conservation

  20. What about birds? • One-way ventilation mechanism • Only with birds • Air coming in goes FIRST to posterior air sacs • Then lungs to anterior air sacs • No air mixing occurs, better gas exchange efficiency.

  21. Respiratory Gas Exchange • Mainly by diffusion • How O2 gets in/CO2 gets out of tissues and lungs • Partial pressure— • Amount of pressure given off by gases • PO2 , PCO2 • Pressure different causes diffusion to occur • Alveoli– HIGH PO2 , LOW PCO2 • Tissues—LOW PO2, HIGH PCO2

  22. Oxygen Transport • 1) External Respiration • CO2 enters lungs from tissues via hemoglobin, mostly bicarbonate (HCO3-) • Involves carbonic anhydrase • O2 combines with hemoglobin via iron • 2) Internal Respiration • PO2 in tissues < blood PO2 • Oxygen leaves hemoglobin, moves into tissues • PCO2 in tissues > blood PCO2, movies into blood

  23. Excretory/Urinary System

  24. Osmoregulation Overview • Water and salt balance in body • Doubles as excretory system

  25. Osmoregulation (cont.) • 1) Aquatic Vertebrates • Main function of kidneys: urine production • Cartilaginous fish: excrete urea, plasma isotonic in seawater • Marine bony fish: potential for dehydration due to hypertonic environment, always “drinking” water • Freshwater bony fish: potential to gain TOO much water, make “dilute” urine, no drinking of water

  26. Osmoregulation (cont.) • 2) Terrestrial Vertebrates • Specialized glands to get rid of salt • Ex. Sea birds • Kidneys produce concentrated urine • Prevents dehydration and enhances water conservation • Ex. Kangaroo rat

  27. Excretion • Metabolic waste removal • Many molecules broken down into nitrogen-containing compounds • Toxic in excess so removal necessary • 3 methods of removal • 1) Ammonia • 2) Urea • 3) Uric Acid

  28. 1. Ammonia Excretion • Amino groups formed from immediate removal from amino acids • Easily eliminated, no energy needed • Potentially toxic, requires lots of water available • Ex. Fish, animals with gills in aquatic environment.

  29. 2. Urea Excretion • Moderately toxic, can be eliminated as a slightly toxic substance • Helps with water conservation • Production via liver, does require energy • Ex. Sharks, amphibians, mammals

  30. 3. Uric Acid • Very energy intensive • Requires a series of reactions to be produced • Does not dissolve in water, great for water conservation • Least toxic • Protects reptilian and bird eggs from toxic nitrogen excess in developing eggs • Ex. Insects, reptiles, birds, humans occasionally.

  31. Invertebrate Excretion • 1) Flatworms • Excretory tubules that secrete wastes through pores • Removes water and waste • 2) Earthworms • Nephridia located at every segment and reabsorbs nutrients • Urine eliminated via pores • 3) Insects • Malpighian tubules • Uric acid moves from hemolymph to tubules • Water moves down salt gradient • Reabsorption occurs at rectum but uric acid eliminated • Aquatic---waste removal through gills

  32. Homework • Read Chapter 35, pp. 681-684 • Pp. 678-679, “Testing Yourself” #1-13

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