Gas Exchange in Animals

1. Gas Exchange in Animals

2. Gas Exchange exchange of O2 and CO2 only via diffusion reservoir for O2 is atmosphere respiratory medium respiratory surface

3. Comparison of Respiratory Media water vs. air content rate of diffusion energy required to move medium over respiratory surface modification of body plan to allow for diffusion

5. Temperature and O2 Availability all water breathers are ectotherms as temperature rises, so does energy use and oxygen demand (Q10 relationship)

6. Temperature Effects as temp increases, dissolved O2 in water decreases as temperature increases, metabolism increases (Q10) animal performs more work to pass water over exchange surfaces

8. Altitude as altitude increases, oxygen content in the air decreases

9. Air air is a gas mixture 78.6% Nitrogen 20.9% Oxygen 0.46% Inert gases 0.04% Carbon dioxide and other inert gases air pressure is measured in atm or mmHg 760 mmHg is pressure at sea level

10. Partial Pressures in Air Dalton�s Law of Partial Pressures Ptotal = Pgas 1 + Pgas 2 + � pressure of each gas in a mixture is the partial pressure of the gas total pressure is equal to the sum of the partial pressures at sea level, the pO2 is about 159 mmHg

11. Gas Exchange problem solution enlarge respiratory surface gills, trachea, and lungs

13. Gas Exchange Systems composed of respiratory surface mechanisms used to ventilate and perfuse

14. Insect Tracheae system of air tubules open to the environment via spiracles branch to within micrometers of every mitochondrion limits size of animal as a result of diffusion rate

16. Fish Gills supported by 4 bony gill arches opercular flaps cover gills water flows into the mouth, over the gills, and under the opercular flap gill arches are lined with 100�s of gill filaments filaments are flat and have folds called lamellae gas exchange surface

17. Fish Gills afferent vessels efferent vessels countercurrent flow

21. Lungs internal structure surrounded by capillaries provide large surface area

22. Bird Lungs lungs and air sacs air sacs interconnect air sacs are not sites of gas exchange

23. Bird Lungs trachea ? bronchi ? parabronchi distribute air parabronchi conduct air unidirectionally through lungs air capillaries sites of gas exchange create enormous surface area

27. Mammalian Lungs breathing is tidal lungs are dead end sacs air enters and exits along the same route located in pleural cavity

28. Tidal Breathing problems: 1. incoming air mixes with stale air from lungs 2. doesn�t allow for countercurrent exchange between air and blood

29. Flow of Air From One Inspiration

34. Pulmonary Ventilation negative pressure breathing action of the diaphragm and external intercostal muscles pleural membranes surround lung pleural fluid lungs cling to thoracic cavity wall

35. Pulmonary Ventilation inhalation creates negative pressure in lungs exhalation creates higher pressure in lungs than in external environment

37. Gas Transport in Blood O2 is transported by hemoglobin in RBC�s Hb reversibly binds O2 in the alveoli amount is dependent upon pO2 releases some O2 around tissues that have low pO2 levels O2 binding is sigmoidal oxygen binding exhibits positive cooperativity

40. Hb�s Affinity for O2 Hb�s affinity for O2 is variable dependent upon numerous factors pH Bohr Effect as plasma pH falls, the O2 binding curve shifts to the right causes Hb to release more O2

42. CO2 Transport transported in the blood as a bicarbonate ion CO2 + H2O ? H2CO3 ? H+ + HCO3- carbonic anhydrase

45. Smoking and Disease accounts for 440,000 deaths, 1 in 5 deaths in the U.S. smoking kills more people than human immunodeficiency virus (HIV), illegal drug use, alcohol use, motor vehicle injuries, suicides, and murders combined

46. Smoking and Disease smoking can cause the following pathologies: lung cancer chronic lung disease coronary heart disease stroke pulmonary embolism acute myeloid leukemia periodontitis

47. Smoking and Disease artherosclerosis peptic ulcers stomach, cervical, kidney, oral, pharynx, tracheal, penile, vaginal, anal, and bladder cancers reduced fertility lower birth weight babies Buerger�s disease nicotine poisoning

48. Smoking and Disease tobacco amblyopia cataracts back pain (disk degeneration) Crohn�s disease wrinkling, leathery skin deficient sense of smell aortic aneurysm COPD

52. Costs of Smoking over $150 billion in annual health-related economic losses from 1995 to 1999 including $81.9 billion in mortality-related productivity losses (average for 1995�1999) and $75.5 billion in excess medical expenditures in 1998 caused an estimated 264,087 male and 178, 311 female deaths in the United States each year from 1995 to 1999

53. Costs of Smoking excluding adult deaths from exposure to secondhand smoke, adult males and females lost an average of 13.2 and 14.5 years of life respectively, because they smoked smoking during pregnancy resulted in an estimated 599 male infant and 408 female infant deaths annually

54. Costs of Smoking annually, exposure to secondhand smoke (or environmental tobacco smoke) causes an estimated 3,000 deaths from lung cancer among American adults At TCTC, smoking is not be permitted within the perimeter of the campus. Smoking will only be allowed 50� away from buildings and in designated areas