Mini-FRQ

1. Mini-FRQ Enzymes are a huge part of digestion Describe structure and function of an enzyme How are enzymes tied to digestion?

2. Why do we breathe oxygen?

3. alveoli Gas Exchange Respiratory Systems elephantseals gills

4. food O2 ATP CO2 Why do we need a respiratory system? • Need O2 in • for aerobic cellular respiration • make ATP • Need CO2 out • waste product fromKrebs cycle

5. Gas exchange • O2 & CO2 exchange between environment & cells • need moist membrane • need high surface area

6. Optimizing gas exchange • Why high surface area? • maximizing rate of gas exchange • CO2 & O2 move across cell membrane by diffusion • rate of diffusion proportional to surface area • Why moist membranes? • moisture maintains cell membrane structure • gases diffuse only dissolved in water High surface area?High surface area!Where have we heard that before?

7. Evolution of gas exchange structures Aquatic organisms external systems with lots of surface area exposed to aquatic environment Terrestrial moist internal respiratory tissues with lots of surface area

8. Lungs Exchange tissue:spongy texture, honeycombed with moist epithelium Why is this exchangewith the environmentRISKY?

9. Mammalian respiratory systems • Bronchi (tube to lungs) • Bronchioles • Alveoli (air sacs) • Diaphragm (breathing muscle) • Larynx (upper part of respiratory tract) • Vocal cords (sound production) • Trachea (windpipe)

10. Alveoli • Gas exchange across thin epithelium of millions of alveoli • total surface area in humans ~100 m2

11. Negative pressure breathing • Breathing due to changing pressures in lungs • air flows from higher pressure to lower pressure • pulling air instead of pushing it

12. Take out April calendar • Share plan with tablemates to get A or B on all April quizzes 2) Change Sat, April 21 to Sat, April 14th 3) Come up with a structure is ties to function example

13. Counter current exchange system • Water carrying gas flows in one direction, blood flows in opposite direction Why does it workcounter current?Adaptation! just keepswimming….

14. water blood How counter current exchange works back front 70% 40% • Blood & water flow in opposite directions • maintains diffusion gradient over whole length of gill capillary • maximizing O2 transfer from water to blood 100% 15% water 60% 30% counter-current 90% 5% blood 50% 70% 100% 50% 30% 5% concurrent

15. Gas Exchange on Land • Advantages of terrestrial life • air has many advantages over water • higher concentration of O2 • O2 & CO2 diffuse much faster through air • respiratory surfaces exposed to airdo not have to be ventilated as thoroughly as gills • air is much lighter than water & therefore much easier to pump • expend less energy moving air in & out • Disadvantages • keeping large respiratory surface moist causes high water loss • reduce water loss by keeping lungs internal Why don’t land animalsuse gills?

16. Terrestrial adaptations • air tubes branching throughout body • gas exchanged by diffusion across moist cells lining terminal ends, not through open circulatory system Tracheae

17. Mechanics of breathing • Air enters nostrils • filtered by hairs, warmed & humidified • sampled for odors • Pharynx  glottis  larynx (vocal cords)  trachea (windpipe)  bronchi  bronchioles  air sacs (alveoli) • Epithelial lining covered by cilia & thin film of mucus • mucus traps dust, pollen, particulates • beating cilia move mucus upward to pharynx, where it is swallowed

18. ATP CO2 O2 Breathing and Homeostasis • Homeostasis • keeping the internal environment of the body balanced • need to balance O2 in and CO2 out • need to balance energy (ATP) production • Exercise • breathe faster • need more ATP • bring in more O2 & remove more CO2 • Disease • poor lung or heart function = breathe faster • need to work harder to bring in O2 & remove CO2

19. Hemoglobin • Why use a carrier molecule? • O2 not soluble enough in H2O for animal needs • blood alone could not provide enough O2 to animal cells • hemocyanin in insects = copper (bluish/greenish) • hemoglobin in vertebrates = iron (reddish) • Reversibly binds O2 • loading O2 at lungs or gills & unloading at cells heme group cooperativity

20. Cooperativity in Hemoglobin • Binding O2 • binding of O2 to 1st subunit causes shape change to other subunits • conformational change • increasing attraction to O2 • Releasing O2 • when 1st subunit releases O2, causes shape change to other subunits • conformational change • lowers attraction to O2

21. Tissue cells CO2 Carbonic anhydrase CO2 dissolves in plasma CO2 + H2O H2CO3 H2CO3 H+ + HCO3– CO2 combines with Hb Cl– HCO3– Plasma Transporting CO2 in blood • Dissolved in blood plasma as bicarbonate ion carbonic acid CO2 + H2O  H2CO3 bicarbonate H2CO3  H+ + HCO3– carbonic anhydrase

22. Lungs: Alveoli CO2 CO2 dissolved in plasma CO2 + H2O H2CO3 HCO3 – + H+ H2CO3 Hemoglobin + CO2 HCO3–Cl– Plasma Releasing CO2 from blood at lungs • Lower CO2 pressure at lungs allows CO2 to diffuse out of blood into lungs

23. Chapter 42 ~ • Circulation and Gas Exchange

24. Exchange of materials • Animal cells exchange material across their cell membrane • fuels for energy • nutrients • oxygen • waste (urea, CO2) • If you are a 1-cell organism that’s easy! • diffusion • If you are many-celled that’s harder

25. In circulation… • What needs to be transported • nutrients & fuels • from digestive system • respiratory gases • O2 & CO2 from & to gas exchange systems: lungs, gills • intracellular waste • waste products from cells • water, salts, nitrogenous wastes (urea) • protective agents • immune defenses • white blood cells & antibodies • blood clotting agents • regulatory molecules • hormones

26. Circulatory systems • All animals have: • circulatory fluid = “blood” • tubes = blood vessels • muscular pump = heart open closed hemolymph blood

27. Open circulatory system • Taxonomy • invertebrates • insects, arthropods, mollusks • Structure • no separation between blood & interstitial fluid • hemolymph

28. Closed circulatory system closed system = higher pressures • Taxonomy • invertebrates • earthworms, squid, octopuses • vertebrates • Structure • blood confined to vessels & separate from interstitial fluid • 1 or more hearts • large vessels to smaller vessels • material diffuses between blood vessels & interstitial fluid

29. Vertebrate circulatory system • Adaptations in closed system • number of heart chambers differs 2 3 4 high pressure & high O2to body low pressureto body low O2to body What’s the adaptive value of a 4 chamber heart? 4 chamber heart is double pump = separates oxygen-rich & oxygen-poor blood; maintains high pressure

30. Circulation system evolution • Fish: 2-chambered heart; single circuit of blood flow • Amphibians: 3-chambered heart; 2 circuits of blood flow- pulmocutaneous (lungs and skin); systemic (some mixing) • Mammals: 4-chambered heart; double circulation; complete separation between oxygen-rich and oxygen poor blood

31. Evolution of 4-chambered heart • Selective forces • increase body size • protection from predation • bigger body = bigger stomach for herbivores • endothermy • can colonize more habitats • flight • decrease predation & increase prey capture • Effect of higher metabolic rate • greater need for energy, fuels, O2, waste removal • endothermic animals need 10x energy • need to deliver 10x fuel & O2 to cells convergentevolution

32. Vertebrate cardiovascular system • Chambered heart • atrium = receive blood • ventricle = pump blood out • Blood vessels • arteries = carry blood away from heart • arterioles • veins = return blood to heart • venules • capillaries = thin wall, exchange / diffusion • capillary beds = networks of capillaries

33. Blood vessels arteries veins artery arterioles venules arterioles capillaries venules veins

34. Arteries: Built for high pressure pump • Arteries • thicker walls • provide strength for high pressure pumping of blood • narrower diameter • elasticity • elastic recoil helps maintain blood pressure even when heart relaxes

35. Veins: Built for low pressure flow Blood flows toward heart • Veins • thinner-walled • wider diameter • blood travels back to heart at low velocity & pressure • lower pressure • distant from heart • blood must flow by skeletal muscle contractions when we move • squeeze blood through veins • valves • in larger veins one-way valvesallow blood to flow only toward heart Openvalve Closed valve

36. Capillaries: Built for exchange • Capillaries • very thin walls • lack 2 outer wall layers • only endothelium • enhances exchange across capillary • diffusion • exchange between blood & cells

37. Controlling blood flow to tissues • Blood flow in capillaries controlled by pre-capillary sphincters • supply varies as blood is needed • after a meal, blood supply to digestive tract increases • during strenuous exercise, blood is diverted from digestive tract to skeletal muscles • capillaries in brain, heart, kidneys & liver usually filled to capacity sphincters open sphincters closed

38. Exchange across capillary walls Lymphatic capillary Fluid & solutes flows out of capillaries to tissues due to blood pressure • “bulk flow” • Interstitial fluid flows back into capillaries due to osmosis • plasma proteins  osmotic pressure in capillary BP > OP BP < OP Interstitial fluid What aboutedema? Blood flow 85% fluid returns to capillaries Capillary 15% fluid returns via lymph Arteriole Venule

39. Blood • Plasma: liquid matrix of blood in which cells are suspended (90% water) • Erythrocytes(RBCs): transport O2 via hemoglobin • Leukocytes (WBCs): defense and immunity • Platelets: clotting • Stem cells: pluripotent cells in the red marrow of bones • Blood clotting: fibrinogen (inactive)/ fibrin (active); hemophilia; thrombus (clot)

40. Lymphatic system • Parallel circulatory system • transports white blood cells • defending against infection • collects interstitial fluid & returns to blood • maintains volume & protein concentration of blood • drains into circulatory system near junction of vena cava & right atrium

41. Lymph system Production & transport of WBCs Traps foreign invaders lymph vessels (intertwined amongst blood vessels) lymph node

42. Mammalian heart to neck & head& arms Coronary arteries

43. Mammaliancirculation systemic pulmonary systemic What do bluevs.redareas represent?

44. Coronary arteries bypass surgery

45. Valves • http://www.smm.org/heart/heart/pumping.htm

46. SL AV AV Heart valves • 4 valves in the heart • flaps of connective tissue • prevent backflow • Atrioventricular (AV) valve • between atrium & ventricle • keeps blood from flowing back into atria when ventricles contract • “lub” • Semilunar valves • between ventricle & arteries • prevent backflow from arteries into ventricles while they are relaxing • “dub”

47. Lub-dub, lub-dub • Heart sounds • closing of valves • “Lub” • recoil of blood against closed AV valves • “Dub” • recoil of blood against semilunar valves • Heart murmur • defect in valves causes hissing sound when stream of blood squirts backward through valve SL AV AV

48. 110 ____ 70 systolic ________ diastolic pump(peak pressure) _________________ fill(minimum pressure) Cardiac cycle • 1 complete sequence of pumping • heart contracts & pumps • heart relaxes & chambers fill • contraction phase • systole • ventricles pumps blood out • relaxation phase • diastole • atria refill with blood

49. Measurement of blood pressure • High Blood Pressure (hypertension) • if top number (systolic pumping) > 150 • if bottom number (diastolic filling) > 90

50. Cardiovascular disease • Cardiovascular disease (>50% of all deaths) • Heart attack- death of cardiac tissue due to coronary blockage • Stroke- death of nervous tissue in brain due to arterial blockage • Atherosclerosis: arterial plaques deposits • Arteriosclerosis: plaque hardening by calcium deposits • Hypertension: high blood pressure • Hypercholesterolemia: LDL, HDL