Circulatory Systems

1. Circulatory Systems

2. Transport Systems fluid system that transports nutrients, gases, and metabolic wastes reduces diffusion distance transport and gas exchange are related functionally

3. Transport Systems Phylum Porifera seawater through spongocoel Phylum Cnidaria gastrovascular cavity is fluid filled and ciliated may branch into tentacles

5. Transport Systems Phylum Platyhelminthes branched gastrovascular cavity no circulatory system, so limited in size

6. Circulatory Systems open circulatory system Phylum Arthropoda, Phylum Mollusca (with one exception) hemolymph heart(s) ? sinuses ? ostia ? heart(s)

8. Circulatory Systems closed circulatory system Phylum Annelida, Subphylum Vertebrata, Class Cephalopoda blood vessels

10. Advantages of Closed Circulatory System 1. rapid flow 2. may direct blood to specific tissues 3. blood cells and large molecules remain within vessels

11. Fish Heart 2 chambered hearts atrium and ventricle aorta

12. Fish Heart blood flow: atrium ? ventricle gills ? aorta ? atrium

13. Fish Heart blood pressure from ventricle is reduced in gills low pressure in aorta

14. Fish Circulatory System evolutionary intermediate: African lungfish exposed to dry conditions or low O2 water outpocketing of gut air is gulped blood vessels surrounding the �lung� take up the O2

15. Fish Circulatory System partially divided atrium left side of atrium receives oxygenated blood (to tissues) right side receives deoxygenated blood (to lung or gills)

16. Amphibian Heart pulmonary and systemic circulation are partly separated 1 ventricle pumps blood to lungs and tissues 2 atria: rt. atrium receives deoxygenated blood lt. atrium receives oxygenated blood

17. Amphibian Heart blood flow: rt. atrium ventricle ? lung ? lt. atrium ? ventricle ? aorta ? body tissues

18. Amphibian Heart advantage over fish heart: separation of pulmonary and systemic circuits reduces resistance resistance no longer lies between heart and tissues

19. Reptilian Heart 2 atria 1 ventricle (2 ventricles in crocodiles and alligators) partially divided, decreases mixing may stop sending blood to lungs when not breathing

20. Reptilian Heart 2 aorta 1 aorta can receive blood from the rt. or lt. side of the ventricle constricts vessels in lung, increasing resistance

21. Reptilian Heart advantage for crocodiles and alligators: generation of different pressures when the heart contracts allows them to operate efficiently over a wide range of metabolic demands

22. Bird and Mammalian Heart 4 chambered heart: 2 atria 2 ventricles full separation of pulmonary and systemic circuits

23. Bird and Mammalian Heart Advantages: 1. no mixing of oxygenated and deoxygenated blood 2. gas exchange is maximized 3. separation allows for pulmonary and systemic circuits to operate at different pressures

24. Bird and Mammalian Heart important because: 1. endothermic high nutrient and O2 demands in tissues 2. high number of vessels great deal of resistance, so requires high pressure

25. Blood Flow in Mammals rt. side of heart: pulmonary circuit lt. side of heart: systemic circuit

26. Blood Flow in Mammals one way valves: atrioventricular valves semilunar valves

27. Blood Flow in Mammals 1. right atrium receives deO2 blood from superior and inferior venae cavae 2. from right atrium into the right ventricle through the tricuspid valve 3. pumped into the pulmonary artery through the pulmonary semilunar valve to lungs

28. Blood Flow in Mammals 4. O2 blood from lungs is returned to the left atrium via the pulmonary veins 5. enters the left ventricle via the mitrial or bicuspid valve 6. exits the left ventricle into the aorta via the aortic semilunar valve 7. circulated to body tissues

30. Cardiac Cycle atrial contraction followed by ventricular contraction systole diastole

32. Elicitation of a Heartbeat coordination is important gap junctions pacemakers

33. Elicitation of Heartbeat 1. pacemaker cells located at junction of superior venae cavae and rt. atrium form the sinoatrial node (SA node) cause atria to contract synchronously no gap junctions between atria and ventricles

34. Elicitation of a Heartbeat 2. signal passes through atrioventricular node (AV node) found in the floor of the rt. atrium imposes a short delay before ventricles contract 3. signal passes to the bundle of His which then transmits the signal to Purkinje fibers

37. The Vascular System arteries and arterioles capillaries veins and venules

39. Physical Laws Frank- Starling Law Law of Continuity

41. Regulation of Circulation arterioles regulate circulation smooth muscle contracts in an arteriole, slowing flow into the capillaries it feeds pre-capillary sphincters nervous and endocrine control

43. Lymphatic Vessels return fluid that accumulates from leaky capillaries lymph nodes

44. Blood transports fluids, cells, gases, biological molecules, and wastes 1. plasma 2. formed elements from pluripotent stem cells

46. Plasma about 90% water and dissolved substances plasma proteins albumins- regulate osmotic pressure globulins- nutrient transport and immune function fibrinogen- blood clotting protein

47. Erythrocytes transport respiratory gases about 5 million per mm3 biconcave, providing larger S.A. contain hemoglobin 1/3 of cell mass binds O2 contains Fe

48. Red Blood Cells short life span (about 120 days) spleen and liver remove dead cells no nucleus in mammals myoglobin form of hemoglobin found in muscle stores O2

49. Respiratory Pigments 1. hemoglobin 2. chlorocruorin 3. hemerythrin 4. hemocyanin

50. Hemoglobin formed in red bone marrow 4 subunits termed hemes 2 alpha and 2 beta subunits porphyrin ring with Fe bound in the center

51. Hemoglobin found in all vertebrates, most plants, protists, etc. each subunit may bind one oxygen molecule binds weakly releases oxygen in regions of low O2 concentration

52. Hemoglobin negative feedback regulates RBC numbers erythropoietin secreted in kidney causes production of RBC�s in red bone marrow about 2 million RBC�s produced per second when oxygen levels are normal, kidneys cease production of erythropoietin

53. Chlorocruorin Class Polychaeta contain Fe green in low oxygen, red when saturated

54. Hemerythrin one genus of annelids and other invertebrates (e.g. Brachiopods) violet-pink when oxygenated, colorless when deoxygenated contains Fe

55. Hemocyanin some crustaceans and arachnids blue when oxygenated and colorless when deoxygenated contain Cu

56. Leukocytes 4000 to 11000 per cubic mm3 less than 1% of blood volume protect body against invasive organisms and tumor cells diapedesis move via amoeboid motion and are positively chemotactic

58. Platelets fragments of megakaryocytes about 300,000 per mm3 blood function in clotting process

60. Hemostasis the cessation of blood flow fast and localized 3 phases: 1. vascular spasms 2. platelet plug formation 3. coagulation

61. Hemostasis vascular spasms and platelet plug formation endothelial lining is broken, platelets adhere, releasing serotonin serotonin causes blood vessels to spasm platelets form a temporary �plug�

62. Clotting Cascade thromboplastin is released from damaged tissue PF3 on the platelet interacts with thromboplastin, activating a clotting cascade prothrombin activating factor converts prothrombin in the plasma to thrombin, an enzyme thrombin converts fibrinogen into insoluble fibrin

65. Diving Physiology animals that dive: greater blood volume more myoglobin in muscles diving reflex