Chapter 23 Circulation

Transcription

1 Chapter 23 Circulation PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Lecture by Edward J. Zalisko

2 Introduction: How Does Gravity Affect Blood Circulation? The circulatory system of a giraffe and corn snake must Overcome gravity Transport O 2 and nutrients to cells Take away CO 2 and other wastes

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6 Introduction: How Does Gravity Affect Blood Circulation? Giraffes have Very strong hearts Higher blood pressure Sinuses that function like check valves to lower pressure to head when bending down Valves in veins of legs to keep blood moving upward Snakes have Hearts close to head Constricting blood vessels to prevent too much blood in one region

7 MECHANISMS OF INTERNAL TRANSPORT

8 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

9 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

10 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

11 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

12 Pores Tubular heart

13 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

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

15 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

16 Gill capillaries Heart: Ventricle (V) Atrium (A) Systemic capillaries

17 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

18 Lung and skin capillaries Pulmocutaneous circuit A V Right Systemic circuit A Left Systemic capillaries

19 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

20 Lung capillaries Pulmonary circuit A V Right Systemic circuit A V Left Systemic capillaries

21 THE HUMAN CARDIOVASCULAR SYSTEM

22 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

23 Superior vena cava 8 Capillaries of head, chest, and arms Pulmonary artery Pulmonary artery Capillaries of right lung 9 2 Aorta 7 2 Capillaries of left lung Pulmonary vein Right atrium Pulmonary vein Left atrium Right ventricle Left ventricle Inferior vena cava Aorta 8 Capillaries of abdominal region and legs

24 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

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

26 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

27 1 Heart is relaxed. Semilunar valves closed AV valves are open. 0.4 sec Diastole

28 1 Heart is relaxed. Semilunar valves closed 2 Atria contract. AV valves are open. 0.4 sec 0.1 sec Systole Diastole

29 1 Heart is relaxed. Semilunar valves closed 2 Atria contract. AV valves are open. 0.4 sec 0.1 sec 0.3 sec Systole 3 Ventricles contract. Diastole Semilunar valves are open. AV valves closed

30 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

31 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

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

33 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

34 Heart

35 23.6 CONNECTION: What is a heart attack? A heart attack is damage to cardiac muscle Stroke Typically from a blocked coronary artery Death of brain tissue from blocked arteries in the head

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

37 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

38 Connective tissue Smooth muscle Epithelium Plaque

39 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

40 Red blood cell Capillary Nuclei of smooth muscle cells

41 Capillary Interstitial fluid Diffusion of molecules Tissue cell

42 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

43 Epithelium Capillary Basal lamina Valve Epithelium Smooth muscle Connective tissue Epithelium Smooth muscle Connective tissue Artery Vein Arteriole Venule

44 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

45 Aorta Arteries Arterioles Capillaries Venules Veins Venae cavae Velocity (cm/sec) Pressure (mm Hg) Diastolic pressure Systolic pressure Relative sizes and numbers of blood vessels

46 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

47 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

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

49 23.9 CONNECTION: Measuring blood pressure can reveal cardiovascular problems Hypertension is a serious cardiovascular problem Consistent pressures above either 140 systolic 90 diastolic

50 Typical blood pressure 120 systolic 70 diastolic Rubber cuff inflated with air Pressure in cuff above Artery Artery closed 1 2

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

52 Typical blood pressure 120 systolic 70 diastolic Rubber cuff inflated with air Pressure in cuff above Pressure in cuff at Pressure in cuff at Artery Artery closed Sounds audible in stethoscope Sounds stop

53 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

54 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

55 Precapillary sphincters Thoroughfare channel Arteriole 1 Sphincters relaxed Capillaries Venule Thoroughfare channel Arteriole Venule 2 Sphincters contracted

56 Precapillary sphincters Thoroughfare channel Capillaries Arteriole Venule 1 Sphincters relaxed

57 Thoroughfare channel Arteriole Venule 2 Sphincters contracted

58 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

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

60 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

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

62 STRUCTURE AND FUNCTION OF BLOOD

63 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

64 Plasma (55%) Constituent Water Ions (blood electrolytes) Sodium Potassium Calcium Magnesium Chloride Bicarbonate Plasma proteins Fibrinogen Immunoglobulins (antibodies) Major functions Solvent for carrying other substances Osmotic balance, ph buffering, and maintaining ion concentration of interstitial fluid Osmotic balance and ph buffering Clotting Defense Centrifuged blood sample Substances transported by blood Nutrients (e.g., glucose, fatty acids, vitamins) Waste products of metabolism Respiratory gases (O 2 and CO 2 ) Hormones

65 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

66 Cellular elements (45%) Cell type Number per µl (mm 3 ) of blood Functions Centrifuged blood sample Erythrocytes (red blood cells) 5 6 million Transport of oxygen (and carbon dioxide) Leukocytes (white blood cells) 5,000 10,000 Defense and immunity Basophil Lymphocyte Eosinophil Neutrophil Monocyte Platelets 250, ,000 Blood clotting

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

68 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

69 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

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71 23.14 Blood clots plug leaks when blood vessels are injured When a blood vessel is damaged Platelets help trigger the conversion of fibrinogen to fibrin Which forms a clot that plugs the leak

72 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 A fibrin clot traps blood cells

73 1 Platelets adhere to exposed connective tissue Epithelium Connective tissue Platelet

74 1 Platelets adhere to exposed connective tissue 2 Platelet plug forms Epithelium Connective tissue Platelet Platelet plug

75 1 Platelets adhere to exposed connective tissue 2 Platelet plug forms 3 Fibrin clot traps blood cells Epithelium Connective tissue Platelet Platelet plug

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77 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

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

79 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

80 Capillary Basement membrane Epithelium Valve Smooth muscle Connective tissue Artery Vein

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

82 a. b.

83 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

84 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

85 You should now be able to 9. Describe the process of blood clotting 10. Describe the causes and treatments for leukemia