Chapter 05 Cardiovascular System

Transcription

1 Chapter 05 Cardiovascular System 1

2 Cardiovascular System: Heart and Blood Vessels 2

3 Points to ponder What are the functions of the cardiovascular system? What is the anatomy of the heart? Of blood vessels, such as veins and arteries? How is the heart beat regulated? What is blood pressure? What are common cardiovascular diseases and how might you prevent them? 3

4 5.1 Overview of the Cardiovascular System What is the cardiovascular system? Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CO 2 O 2 Includes Heart & blood vessels Functions: Respiratory System tissue cells Organs that refresh blood: Cardiovascular System What s involved? food kidneys liver Figure 5.1 The cardiovascular system and homeostasis. Digestive System indigestible food residues (feces) Urinary System metabolic wastes (urine) 4

5 5.3 The Heart is a Double Pump External anatomy of the heart left subclavian artery left common carotid artery brachiocephalic artery superior vena cava aorta left pulmonary artery pulmonary trunk left pulmonary veins right pulmonary artery right pulmonary veins left atrium left cardiac vein right atrium right coronary artery left ventricle right ventricle left anterior descending coronary artery inferior vena cava apex Figure 5.3 The arteries and veins associated with the human heart. 5

6 5.3 The Heart is a Double Pump Internal anatomy of the heart Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. left subclavian artery left common carotid artery brachiocephalic artery superior vena cava aorta left pulmonary artery pulmonary trunk left pulmonary veins right pulmonary artery right pulmonary veins semilunar valve left atrium right atrium atrioventricular (bicuspid) valve atrioventricular (tricuspid) valve chordae tendineae papillary muscles right ventricle septum left ventricle inferior vena cava a. Figure 5.4a The heart is a double pump. 6

7 Figure 42.7 Pulmonary artery Right atrium Aorta Pulmonary artery Left atrium Pulmonary Semilunar valve Atrioventricular Valve Tricuspid Aortic Semilunar valve Atrioventricular Valve Bicuspid/Mitral Right ventricle Left ventricle 7

8 5.3 The Heart is a Double Pump Visualizing blood flow through the heart Intercalated disc with gap junctions Figure 5.4 The heart is a double pump. 8

9 LM 15 m LM Main pathway of blood in the body? Artery Vein Red blood cells 100 m Valve Figure Basal lamina Endothelium Endothelium Smooth muscle Smooth muscle Connective tissue Capillary Connective tissue Artery Vein Arteriole Venule Red blood cell Capillary 9

10 5.5 Two Cardiovascular Pathways What are the 2 cardiovascular pathways Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. in the body? jugular vein (also subclavian vein from arms) CO 2 head and arms O 2 carotid artery (also subclavian artery to arms) Pulmonary circuit Systemic circuit pulmonary artery CO 2 O 2 O 2 CO 2 lungs pulmonary vein superior vena cava aorta heart inferior vena cava hepatic vein hepatic portal vein liver digestive tract intestinal artery renal artery renal vein iliac vein kidneys iliac artery Figure 5.10 Overview of the cardiovascular system. CO 2 trunk and legs O 2 10

11 5.5 Two Cardiovascular Pathways Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. common carotid artery internal jugular vein superior vena cava external jugular vein subclavian artery subclavian vein inferior vena cava renal artery abdominal aorta mesenteric vein common iliac vein renal vein inferior mesenteric artery common iliac artery femoral artery femoral vein great sphenoid vein Figure 5.11 The major arteries and veins of the systemic circuit. 11

12 5.2 The Types of Blood Vessels Arteries, Capillaries, Veins Arteries Arterioles Venules Veins artery connective tissue arteriole v. a. blood flow elastic tissue endothelium precapillary sphincter smooth muscle arteriovenous shunt capillary bed valve venule blood flow vein v. = vein; a. = artery (left): Ed Reschke; (right): Biophoto Associates/Photo Researchers Figure 5.2 Structure of a capillary bed. 12

13 5.2 The Types of Blood Vessels How can you tell the difference between an artery and vein? Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. artery connective tissue arteriole v. a. blood flow elastic tissue endothelium precapillary sphincter smooth muscle arteriovenous shunt valve blood flow venule vein v.=vein; a.=artery (left): Ed Reschke Figure 5.2 Structure of a capillary bed. 13

14 5.3 The Heart is a Double Pump Visualizing the heartbeat Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Internal control SA Node (pacemaker) External control: Medulla oblongata cardiac ctr Sympathetic increase HR Parasympathetic decrease HR Hormones SA node AV node branches of atrioventricular bundle Purkinje fibers a. Figure 5.6a An electrical signal pathway through the heart. 14

15 5.3 The Heart is a Double Pump What does a normal ECG look like? Electrical event (Pacemaker) Electrical event (heart muscle excitement) Mechanical event (heart muscle contraction) R P T SA node Q AV node b. Normal ECG S b: Ed Reschke branches of atrioventricular bundle Purkinje fibers P wave QRS complex T wave Electrical events (heart muscle excitement) lead to mechanical events (contraction) Figure 5.6a-b An electrical signal pathway through the heart. 15

16 5.3 The Heart is a Double Pump What is the cardiac cycle? Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. pulmonary trunk aorta semilunar valves superior vena cava semilunar valves close ( dup ) aortic semilunar valve bicuspid valve right atrium left atrium right atrium a. left ventricle inferior vena cava c. right ventricle aorta pulmonary trunk d. How often does your heart beat? Systolic/diastolic b. atrioventricular (AV) valves close ( lub ) represents contraction Heart sounds (lup dup)? d: Biophoto Associates/ Photo Researchers Figure 5.5 The stages of the cardiac cycle. 16

17 The cardiac cycle aka The Beast 17

18 5.3 The Heart is a Double Pump What is blood pressure? Systole Diastole Average: 120/80 mmhg (systolic/diastolic) Mean arterial pressure (MAP) DP + 1/3 Pulse pressure; (PP = SP DP) 18

19 Cardiac Output Amount ejected by a ventricle in 1 minute CO = Heart Rate x Stroke Volume HR = how many times your heart beats/min SV = volume of blood ejected/beat (ml/beat) Resting values, usually about 4 to 6L/min Vigorous exercise CO to 21 L/min for fit person up to 35 L/min for world class athlete 19

20 Determining Cardiac Output End diastolic volume = End systolic volume = Ejection volume (stroke volume) = Ejection fraction = 70ml/120ml = 58% (normally 60%) If heart rate (HR) is 70 beats/minute, what is cardiac output? Cardiac output = HR * stroke volume = 70 beats/min * 70 ml/beat = 4900 ml/min 4.9 L/min 20

21 Mean Arterial Pressure 21

22 5.4 Features of the Cardiovascular System How blood pressure is measured Figure 5.7 Sphygmomanometers measure blood pressure. 22

23 5.4 Features of the Cardiovascular System How is blood pressure categorized? 23

24 5.2 The Types of Blood Vessels How can you tell the difference between an artery and vein? Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. artery connective tissue arteriole v. a. blood flow elastic tissue endothelium precapillary sphincter smooth muscle arteriovenous shunt valve blood flow venule vein v.=vein; a.=artery (left): Ed Reschke Figure 5.2 Structure of a capillary bed. 24

25 5.4 Features of the Cardiovascular System Relative magnitude What is important about blood flow? Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Blood flow slowest Why??? Pressure greatest arteries arterioles capillaries venules veins blood pressure total cross-sectional area of vessels velocity Blood flow (starting from heart) Pressure minimal, Flow increased Figure 5.8 Blood velocity and pressure in the blood vessels. 25

26 5.4 Features of the Cardiovascular System If blood pressure is so low in the veins, why does the blood flow increase? Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. to heart to heart They have help. Figure 5.9 The skeletal muscle pump. a. Contracted skeletal muscle pushes blood past open valve. b. Closed valve prevents backward flow of blood. 26

27 5.3 The Heart is a Double Pump Coronary circulation Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. left subclavian artery left common carotid artery brachiocephalic artery superior vena cava aorta left pulmonary artery Coronary sinus pulmonary trunk left pulmonary veins right pulmonary artery right pulmonary veins semilunar valve left atrium right atrium atrioventricular (bicuspid) valve atrioventricular (tricuspid) valve chordae tendineae papillary muscles right ventricle septum left ventricle inferior vena cava a. Figure 5.4a The heart is a double pump. 27

28 5.3 The Heart is a Double Pump Coronary circulation left subclavian artery left common carotid artery brachiocephalic artery superior vena cava aorta left pulmonary artery pulmonary trunk left pulmonary veins right pulmonary artery right pulmonary veins left atrium left cardiac vein right atrium right coronary artery left ventricle right ventricle left anterior descending coronary artery inferior vena cava apex Figure 5.3 The arteries and veins associated with the human heart. 28

29 .5 Two Cardiovascular Pathways What is the hepatic portal system? Portal system capillary to capillary Hepatic portal btn intestines & liver Amino acids Glucose cleanses blood from GI tract Returns blood via inferior vena cava 29

30 5.6 Exchange at the Capillaries Exchange at the capillary beds is primarily a result of osmotic and blood pressure Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. from heart to heart Arterial End Blood pressure is higher than osmotic pressure. Net pressure out. water oxygen amino acids Tissue Fluid glucose carbon dioxide wastes Venous End Osmotic pressure is higher than blood pressure. Net pressure in. water salt plasma protein arteriole smooth muscle fiber osmotic pressure blood pressure venule Figure 5.12 The movement of solutes in a capillary bed. 30

31 5.6 Exchange at the Capillaries Exchange at the capillaries Precapillary sphincter Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. arteriole tissue cells lymphatic capillary Figure 5.13 Interaction of lymphatic and capillary beds. blood capillary venule Lymphatic duct with lymph subclavian veins 31

32 5.7 Cardiovascular Disorders Cardiovascular disease (CVD) Disorders of: heart (cardio) and blood vessels (vascular) 32

33 Cardiovascular disease (CVD) Risk Factors 33

34 5.7 Cardiovascular Disorders Disorders of the blood vessels Hypertension/high blood pressure Atherosclerosis Stroke Heart attack Aneurysm 34

35 5.7 Cardiovascular Disorders Hypertension Often due to arterial plaque. 140/90 mmhg is considered hypertension. Silent killer few symptoms It can lead to a heart attack, stroke, or kidney failure 35

36 Hypertension 36

37 5.7 Cardiovascular Disorders Atherosclerosis coronary artery Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. ulceration lumen of vessel fat cholesterol crystals Build up of plaque Biophoto Associates/Photo Researchers Thrombus Embolus dislodged thrombus Associated with stroke, heart attacks and aneurysms atherosclerotic plaque Figure 5B Coronary arteries and plaque. 37

38 Treatments for Atherosclerotic Plaque in Coronary Arteries Bypass surgery Stents: wire mesh cylinder inserted Angioplasty: a tube with a balloon inflated 38

39 5.7 Cardiovascular Disorders Stroke Stroke aka cerebrovascular accident (CVA) Cranial artery is blocked or bursts Part of the brain dies Symptoms may include: numbness of hands or face difficulty speaking inability to see in one eye Sudden burst 39

40 5.7 Cardiovascular Disorders Aneurysm Blood vessel balloons (weaken walls) Atherosclerosis and hypertension Most commonly affected abdominal artery or the arteries leading to the brain. 40

41 5.7 Cardiovascular Disorders Heart attack Heart attack or myocardial infarction (MI) Angina pectoris: 41

42 5.7 Cardiovascular Disorders How are disorders of the blood vessels treated? Dissolving blood clots t-pa (tissue plasmogen activator) drug that dissolves clots 42

43 5.7 Cardiovascular Disorders Disorders of the heart and its treatment Disorders Congestive heart failure Treatments Left ventricular assist device (LVAD) Heart transplant either natural or artificial 43

44 5.7 Cardiovascular Disorders Disorders of the heart and its treatment Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. replacement heart wireless energytransfer system external wireless driver Figure 5.15 An artificial heart. internal controller external battery pack (right): Courtesy SynCardia Systems, Inc. rechargeable internal battery photograph of artificial heart 44

45 5.7 Cardiovascular Disorders Cardiovascular Disease Prevention 45