1. Copyright © 2009 Pearson Education, Inc. MECHANISMS OF INTERNAL TRANSPORT

2. Copyright © 2009 Pearson Education, Inc. 23.1 Circulatory systems facilitate exchange with all body tissues  All cells need –Nutrients –Gas exchange –Removal of wastes  Diffusion alone is inadequate for large and complex bodies

3. Copyright © 2009 Pearson Education, Inc. 23.1 Circulatory systems facilitate exchange with all body tissues  An internal transport system assists diffusion by moving materials between –Surfaces of the body –Internal tissues

4. Copyright © 2009 Pearson Education, Inc. 23.1 Circulatory systems facilitate exchange with all body tissues  A gastrovascular cavity in cnidarians and flatworms serves –Digestion –Distribution of substances  Most animals use a circulatory system –Blood –Heart –Blood vessels

5. Copyright © 2009 Pearson Education, Inc. 23.1 Circulatory systems facilitate exchange with all body tissues  Open circulatory systems –Arthropods and many molluscs –Heart pumps blood through open-ended vessels –Cells directly bathed in blood

6. Pores Tubular heart

7. Copyright © 2009 Pearson Education, Inc. 23.1 Circulatory systems facilitate exchange with all body tissues  Closed circulatory systems –Vertebrates, earthworms, squids, octopuses –Blood stays confined to vessels –A heart pumps blood through arteries to capillaries –Veins return blood to heart

8. Capillary beds Artery (O 2 -rich blood) Arteriole Artery (O 2 -poor blood) Heart Ventricle Atrium Vein Venule Gill capillaries

9. Copyright © 2009 Pearson Education, Inc. 23.2 EVOLUTION CONNECTION: Vertebrate Cardiovascular systems reflect evolution  Two-chambered heart –Fish –Pumps blood in a single circuit –From gill capillaries –To systemic capillaries –Back to heart

10. Gill capillaries Heart: Ventricle (V) Atrium (A) Systemic capillaries

11. Copyright © 2009 Pearson Education, Inc. 23.2 EVOLUTION CONNECTION: Vertebrate Cardiovascular systems reflect evolution  Land vertebrates have double circulation –Separate pulmonary and systemic circuits  Three-chambered hearts –Amphibians, turtles, snakes, lizards –Two atria –One undivided ventricle –Permits blood diversion away from lungs when diving –But some blood from body and lungs mixes in the ventricle when not diving

12. Lung and skin capillaries Pulmocutaneous circuit V Right Systemic capillaries AA Left Systemic circuit

13. Copyright © 2009 Pearson Education, Inc. 23.2 EVOLUTION CONNECTION: Vertebrate Cardiovascular systems reflect evolution  Four-chambered hearts –Crocodilians, birds, mammals –Two atria and two ventricles –Two circuits that do not mix –Right side pumps blood from body to lungs –Left side pumps blood from lungs to body –Higher blood pressure –Supports more efficient movement of blood –Needed in endothermic animals

14. Lung capillaries Pulmonary circuit V Right Systemic capillaries AA Left Systemic circuit V

15. Copyright © 2009 Pearson Education, Inc. THE HUMAN CARDIOVASCULAR SYSTEM

16. Copyright © 2009 Pearson Education, Inc. 23.3 The human cardiovascular system illustrates the double circulation of mammals  Blood flow through the double circulatory system of humans Animation: Path of Blood Flow in Mammals

17. Superior vena cava Pulmonary artery Capillaries of right lung 8 9 2 3 Aorta 4 5 10 1 6 Pulmonary vein 9 Right atrium Inferior vena cava Right ventricle 4 8 3 Pulmonary artery Capillaries of left lung Aorta Pulmonary vein Left atrium Left ventricle 2 7 Capillaries of head, chest, and arms Capillaries of abdominal region and legs

18. Copyright © 2009 Pearson Education, Inc. 23.3 The human cardiovascular system illustrates the double circulation of mammals  The mammalian heart –Two thin-walled atria that –Pump blood –To ventricles –Thick-walled ventricles that –Pump blood –To lungs and all other body regions

19. Right atrium To lung From lung Semilunar valve Atrioventricular (AV) valve Left atrium To lung From lung Semilunar valve Atrioventricular (AV) valve Right ventricle Left ventricle

20. Copyright © 2009 Pearson Education, Inc. 23.4 The heart contracts and relaxes rhythmically  During diastole, blood flows –From veins –Into heart chambers  During systole, blood flows –From atria –Into ventricles

21. Semilunar valves closed 1 Heart is relaxed. AV valves are open. Diastole 0.4 sec

22. Semilunar valves closed 1 Heart is relaxed. AV valves are open. Diastole 0.4 sec 2 Atria contract. Systole 0.1 sec

23. Semilunar valves closed 1 Heart is relaxed. AV valves are open. Diastole 0.4 sec 2 Atria contract. Systole 0.1 sec Semilunar valves are open. 3 Ventricles contract. AV valves closed 0.3 sec

24. Copyright © 2009 Pearson Education, Inc. 23.4 The heart contracts and relaxes rhythmically  Cardiac output –Amount of blood/minute pumped into systemic circuit  Heart rate –Number of beats/minute  Heart valves –Prevent the backflow of blood  Heart murmur –A defect in one or more heart valves

25. Copyright © 2009 Pearson Education, Inc. 23.5 The pacemaker sets the tempo of the heartbeat  The pacemaker (SA node) –Sets the rate of heart contractions –Generates electrical signals in atria  The AV node –Relays these signals to the ventricles

26. Pacemaker (SA node) AV node Right atrium 1 Pacemaker generates signals to contract 2 Signals spread through atria and are delayed at AV node ECG 3 Signals relayed to apex of heart 4 Signals spread through ventricle Apex Specialized muscle fibers

27. Copyright © 2009 Pearson Education, Inc. 23.5 The pacemaker sets the tempo of the heartbeat  An electrocardiogram (ECG) –Records electrical changes in heart  Heart rate normally adjusts to body needs  Abnormal rhythms may occur in a heart attack –External defibrillator can restore rhythm –Implanted artificial pacemakers can trigger normal rhythms

28. Heart

29. Copyright © 2009 Pearson Education, Inc. 23.6 CONNECTION: What is a heart attack?  A heart attack is damage to cardiac muscle –Typically from a blocked coronary artery  Stroke –Death of brain tissue from blocked arteries in the head

30. Blockage Dead muscle tissue Right coronary artery Superior vena cava Pulmonary artery Aorta Left coronary artery

31. Copyright © 2009 Pearson Education, Inc. 23.6 CONNECTION: What is a heart attack?  Atherosclerosis –Plaques develop inside inner walls of blood vessels –Plaques narrow blood vessels –Blood flow is reduced

32. Plaque Epithelium Connective tissue Smooth muscle

33. Copyright © 2009 Pearson Education, Inc. 23.7 The structure of blood vessels fits their functions  Arteries and veins –Lined by single layer of epithelial cells –Smooth muscle in walls can reduce blood flow –Elastic fibers permit recoil after stretching –Veins have one-way valves that restrict backward flow

34. Connective tissue Capillary Venule Smooth muscle Arteriole ArteryVein Valve Epithelium Basal lamina Epithelium Smooth muscle Epithelium Connective tissue

35. Copyright © 2009 Pearson Education, Inc. 23.7 The structure of blood vessels fits their functions  Capillaries –Thin walls—a single layer of epithelial cells –Narrow—blood cells flow in a single file –Increase surface area for gas and fluid exchange

36. Nuclei of smooth muscle cells Red blood cell Capillary

37. Diffusion of molecules Capillary Interstitial fluid Tissue cell

38. Copyright © 2009 Pearson Education, Inc. 23.8 Blood pressure and velocity reflect the structure and arrangement of blood vessels  Blood pressure –The force blood exerts on vessel walls –Depends on –Cardiac output –Resistance of vessels –Decreases as blood moves away from heart

39. Systolic pressure Diastolic pressure 120 100 80 60 40 20 0 Relative sizes and numbers of blood vessels Pressure (mm Hg) Velocity (cm/sec) 50 40 30 20 10 0 Aorta Venae cavae Arteries CapillariesVenulesVeinsArterioles

40. Copyright © 2009 Pearson Education, Inc. 23.8 Blood pressure and velocity reflect the structure and arrangement of blood vessels  Blood pressure is –Highest in arteries –Lowest in veins  Blood pressure is measured as –Systolic pressure—caused by ventricular contraction –Diastolic pressure—low pressure between contractions

41. Copyright © 2009 Pearson Education, Inc. 23.8 Blood pressure and velocity reflect the structure and arrangement of blood vessels  How does blood travel against gravity, up legs? –Pressure from muscle contractions –Between two muscles –Between muscles and bone or skin –Squeezes veins –One-way valves limit blood flow to one direction, towards heart

42. Direction of blood flow in vein Valve (open) Skeletal muscle Valve (closed)

43. Copyright © 2009 Pearson Education, Inc. 23.9 CONNECTION: Measuring blood pressure can reveal cardiovascular problems  Hypertension is a serious cardiovascular problem –Consistent pressures above either –140 systolic –90 diastolic

44. Typical blood pressure 120 systolic 70 diastolic Pressure in cuff above 120 120 Rubber cuff inflated with air Artery closed Artery 1 2 Pressure in cuff at 120 120 Sounds audible in stethoscope 3 70 Sounds stop 4 Pressure in cuff at 70

45. Copyright © 2009 Pearson Education, Inc. 23.9 CONNECTION: Measuring blood pressure can reveal cardiovascular problems  Hypertension causes –Heart to work harder, weakening heart over time –Increased plaque formation from tiny ruptures –Increased risk of blood clot formation  Hypertension can cause –Heart attacks –Strokes –Kidney failure

46. Copyright © 2009 Pearson Education, Inc. 23.10 Smooth muscle controls the distribution of blood  Blood flow through capillaries –Is restricted by smooth muscle sphincters –Only about 5–10% of capillaries are open at one time

47. Capillaries Thoroughfare channel Precapillary sphincters Venule Sphincters relaxed Thoroughfare channel VenuleArteriole 2 1 Sphincters contracted Arteriole

48. Copyright © 2009 Pearson Education, Inc. 23.11 Capillaries allow the transfer of substances through their walls  Capillaries have very thin walls  Substances can cross through these thin walls –Between blood and interstitial fluids

49. Nucleus of epithelial cell Capillary lumen Interstitial fluid Capillary wall Muscle cell Clefts between the epithelial cells of the capillary wall

50. Copyright © 2009 Pearson Education, Inc. 23.11 Capillaries allow the transfer of substances through their walls  Blood and interstitial fluid exchange substances –By diffusion –By pressure flow through clefts between epithelial cells  Blood pressure forces fluid out of capillaries at the arterial end  Osmotic pressure draws in fluid at the venous end

51. Tissue cells Osmotic pressure Interstitial fluid Net fluid movement in Blood pressure Osmotic pressure Venous end of capillary Arterial end of capillary Blood pressure Net fluid movement out

52. Copyright © 2009 Pearson Education, Inc. STRUCTURE AND FUNCTION OF BLOOD

53. Copyright © 2009 Pearson Education, Inc. 23.12 Blood consists of red and white blood cells suspended in plasma  Plasma is about 90% water  Plasma contains –Various inorganic ions –Proteins, nutrients –Wastes, gases –Hormones

54. Copyright © 2009 Pearson Education, Inc. 23.12 Blood consists of red and white blood cells suspended in plasma  Red blood cells (erythrocytes) –Transport O 2 bound to hemoglobin  White blood cells (leukocytes) –Function inside and outside the circulatory system –Fight infections and cancer

55. Plasma (55%) Constituent Osmotic balance, pH buffering, and maintaining ion concentration of interstitial fluid Solvent for carrying other substances Water Ions (blood electrolytes) Major functions Sodium Potassium Calcium Magnesium Chloride Bicarbonate Plasma proteins ClottingFibrinogen Osmotic balance and pH buffering DefenseImmunoglobulins (antibodies) Substances transported by blood Nutrients (e.g., glucose, fatty acids, vitamins) Waste products of metabolism Respiratory gases (O 2 and CO 2 ) Hormones Cellular elements (45%) Centrifuged blood sample Number per µL (mm 3 ) of blood Cell typeFunctions Erythrocytes (red blood cells) 5–6 million Transport of oxygen (and carbon dioxide) Leukocytes (white blood cells) Basophil Lymphocyte Defense and immunity Eosinophil 5,000–10,000 250,000– 400,000 NeutrophilMonocyte Blood clotting Platelets

56. Copyright © 2009 Pearson Education, Inc. 23.14 Blood clots plug leaks when blood vessels are injured  The blood-clotting process –Platelets adhere to exposed connective tissue –Platelets form a plug –Platelets help trigger the conversion of fibrinogen to fibrin –A fibrin clot traps blood cells

57. Platelets adhere to exposed connective tissue 1 Epithelium Connective tissue Platelet

58. Platelets adhere to exposed connective tissue 1 Epithelium Connective tissue Platelet Platelet plug forms 2 Platelet plug

59. Platelets adhere to exposed connective tissue 1 Epithelium Connective tissue Platelet Platelet plug forms 2 Platelet plug Fibrin clot traps blood cells 3

61. Copyright © 2009 Pearson Education, Inc. 23.13 CONNECTION: Too few or too many red blood cells can be unhealthy  Anemia –Abnormally low amounts of hemoglobin or red blood cells –Causes fatigue due to lack of oxygen in tissues

62. Copyright © 2009 Pearson Education, Inc. 23.13 CONNECTION: Too few or too many red blood cells can be unhealthy  Hormone erythropoietin (EPO) –Regulates red blood cell production  Some athletes artificially increase red blood cell production by injecting erythropoietin –Can lead to –Clotting –Stroke –Heart failure –Death

64. Copyright © 2009 Pearson Education, Inc. 23.15 CONNECTION: Stem cells offer a potential cure for blood cell diseases  Stem cells divide in bone marrow –To produce all the types of blood cells throughout life –Are used to treat some blood disorders

65. Multipotent stem cell Lymphoid stem cell Myeloid stem cells Erythrocytes Platelets Eosinophils Basophils Neutrophils Monocytes Lymphocytes

66. Copyright © 2009 Pearson Education, Inc. 23.15 CONNECTION: Stem cells offer a potential cure for blood cell diseases  Leukemia is cancer of white blood cells –Leukemia results in extra leukocytes that do not function properly –Leukemia is usually fatal unless treated –Some treatments –Destroy all bone marrow in the patient –Transplant new bone marrow from a donor with similar bone marrow

67. Capillary Epithelium Valve Basement membrane Connective tissue Smooth muscle VeinArtery

68. a. c. d. e. f. g. h. i. b. p. o. n. m. l. k. j.

69. a. b.

70. Copyright © 2009 Pearson Education, Inc. You should now be able to 1.Explain how the circulatory systems of a giraffe and snake resist gravity 2.Describe the general need for and functions of a circulatory system 3.Compare the structures and functions of gastrovascular cavities, open circulatory systems, and closed circulatory systems 4.Compare the circulatory systems of a fish, frog, and mammal

71. Copyright © 2009 Pearson Education, Inc. You should now be able to 5.Explain how heartbeats are controlled 6.Describe the causes and consequences of a heart attack and cardiovascular disease 7.Relate the structure of blood vessels to their functions 8.Describe the components of blood and their functions

72. Copyright © 2009 Pearson Education, Inc. You should now be able to 9.Describe the process of blood clotting 10.Describe the causes and treatments for leukemia