1. Circulation and Gas Exchange:
    • Unicellular organisms exchange directly with environment.
    • Multicellular organisms cannot exchange directly with environment
    • Complex animals have internal transport systems that circulate fluid.
  2. Gastrovascular Cavity:
    • Simple animals with two cell body walls enclose a gastrovascular cavity.
    • This functions as digestion and distribution.
  3. Open and Closed Circulatory Systems:
    Present with complex animals.
  4. List Three Basic Components of Both Circulatory Systems:
    • Circulatory Fluid [blood(closed) hemolymph(open)]
    • Set of Tubes (blood vessels)
    • Muscular Pump (the heart)
  5. Open Circulatory System:
    • Blood bathes the organs directly
    • Arthropods and Molluscs.
    • Hemolymph = Blood + Internal Fluid.
  6. Closed Circulatory System:
    • Blood is confined to vessels and distinct from interstitial fluid.
    • Closed systems are more efficient at transporting circulatory fluids.
  7. Vertebrate Circulatory System:
    • Vertebrates have a closed circulatory system.
    • Called the cardiovascular system.
  8. Three Main Blood Vessel Types:
    • Arteries
    • Veins
    • Capillaries
  9. Arteries:
    Branch into arterioles and carry blood to capillaries.
  10. Capillaries:
    • Network of capillaries called capillary beds.
    • Site of chemical exchange.
  11. Veins:
    • Venules converge into veins.
    • Return blood from capillaries to heart.
  12. Vertebrate hearts:
    • Contain two or more chambers.
    • Blood enters through an atrium.
    • Pumped out through a ventricle.
  13. Single Circulation:
    • Two-Chambered Heart
    • Blood leaving heart passes two capillary beds before returning.
    • Bony fishes, Rays, and Sharks.
  14. Double Circulation:
    • Amphibian, reptiles, and mammals have double circulation.
    • O2-poor and O2-rich blood pump seperately from right and left sides of heart.
    • Higher blood pressure in organs relative to Single Circulation.
    • Oxygen-rich blood delivers oxygen through systemic circuit.
  15. Oxygen-Poor Blood Flow in Double Circulation:
    • Through pulmonary circuit to get oxygen from lungs. (Most)
    • Through pulmocutaneous circuit to get oxygen from lungs and skin. (Amphibian)
  16. Benefit of Double Circulation:
    Can counteract gravity
  17. Amphibian Heart:
    • Three-chambered heart: two atria and one ventricle.
    • Ventricle pumps blood into forked artery
    • Ventricle output is split to pulmocutaneous circuit and systemic circuit.
    • Blood flow to lungs is nearly shut off underwater.
  18. Reptile (excluding Birds) Heart:
    • Three-chambered heart: two atria and one ventricle.
    • In crocodilians a septum divides the ventricle.
    • Reptiles have a pulmonary circuit (lungs) and a systemic circuit.
  19. Mammal and Bird Heart:
    • Four-chambered heart with two atria and two ventricles.
    • Left side pumps and receives only oxygen-rich blood.
    • Right side receives and pumps only oxygen-poor blood.
    • Endotherms require more O2 than ectotherms.
  20. Gas Exchange:
    • Supplies oxygen for respiration and disposes carbon dioxide.
    • Gas diffuses down pressure gradients in lungs and organs by partial pressure.
  21. Partial Pressure:
    • Pressure exerted by a particular gas in a mixture of gases.
    • A gas diffuses from region of high to low partial pressure.
    • In the lungs and tissues O2 and CO2 diffuse.
    • Animals use air or water as source of respiratory medium.
  22. O2 in Water:
    • There is less O2 available in water than in air.
    • Getting O2 from water needs higher efficiency than breathing.
    • Large, moist respiratory surfaces are needed for gas exchange.
    • Gas exchange takes place by diffusion.
    • Respiratory surfaces can include skin, gills, tracheae, and lungs.
  23. Gills in Aquatic Animals:
    Outfoldings of body creating large surface area for gas exchange.
  24. Ventilation:
    • Moves respiratory medium over respiratory surface.
    • Moving through water or moving water over gills for ventilation.
    • Gills use countercurrent exchange system.
  25. Countercurrent Exchange System:
    • Blood flows in opposite direction to water passing over the gills.
    • Blood is less saturated with O2 than water.
  26. Tracheal System in Insects:
    • Consists of tiny branching tubes that penetrate the body.
    • Tracheal tubes supply O2 directly to body cells.
    • Respiratory and circulatory systems are separate.
    • Larger insects must ventilate their tracheal system to meet O2 demands.
  27. Lungs:
    • Infolding of body surface.
    • Circulatory system transports gases between lungs and rest of body.
    • Size and complexity of lungs correlate with metabolic rate.
  28. Mammalian Respiratory System:
    • System of branching ducts conveys air to lungs.
    • Exhaled air passes over vocal cords to create sounds.
    • Secretions called surfactants coat the surface of the alveoli.
  29. Pathway of Inhaled Air:
    Nostrils > Pharynx > Larynx > Trachea > Bronchi > Bronchioles > Alveoli
  30. Breathing:
    • Ventilating the lungs is breathing.
    • Alternate inhalation and exhalation of air.
  31. How an Amphibian Breathes:
    • An amphibian ventilates lungs by positive pressure breathing.
    • Forces air down the trachea.
  32. How a Mammal Breathes:
    • Mammals ventilate their lungs by negative pressure breathing.
    • Which pulls air into the lungs.
    • Lung volume increases as rib muscles and diaphragm contract.
    • The tidal volume is volume air inhaled with each breath.
    • The maximum tidal volume is the vital capacity.
    • After exhalation residual volume of air remains in lungs.
  33. How a Bird Breathes:
    • Eight or nine air sacs function as bellows keeping air flow.
    • Air passes through lungs in one direction.
    • Every exhalation completely renews air in lungs.
  34. Gas Exchanges:
    Metabolic demands require blood to transport large quantities of O2 and CO2.
  35. Blood Arriving in Lungs:
    • Low partial pressure of O2.
    • High partial pressure of CO2.
    • Relative to air in the alveoli.
  36. Alveoli:
    • O2 diffuses into blood.
    • CO2 diffuses into air.
  37. Tissue capillaries:
    Partial pressure diffuses O2 into interstitial and CO2 into blood.
  38. Respiratory Pigments:
    • Proteins that transport oxygen.
    • Greatly increases amount of oxygen that blood can carry.
    • Arthropods and molluscs have hemocyanin with copper as oxygen-binding component.
    • Most vertebrates and some invertebrates use hemoglobin within erythrocytes.
  39. Hemoglobin:
    • Can carry four molecules of O2.
    • Small change in partial pressure of oxygen means large changes in O2 delivery.
  40. Bohr Shift:
    • CO2 produced in respiration lowers blood pH and hemoglobin affinity for O2.
    • Hemoglobin helps transport CO2 and assists in buffering.
    • CO2 from respiring cells diffuse into blood and transport into either blood plasma, bound to hemoglobin, or bicarbonate ions (HCO3-).
  41. Diving Mammals:
    • Deep-diving air breathers stockpile O2 and deplete it slowly.
    • Weddell seals have high blood to body volume ratio.
    • Also store oxygen in muscles via myoglobin proteins.
Card Set
BIOL 1215-17 Circulation