Pearson's Comprehensive Medical Assisting Administrative and Clinical Competencies

Transcription

1 Pearson's Comprehensive Medical Assisting Administrative and Clinical Competencies THIRD EDITION CHAPTER 27 The Cardiovascular System Lesson 1: Overview of the Cardiovascular System

2 Lesson Objectives Upon completion of this lesson, students should be able to: 1. Define and spell the terms to learn for this chapter. 2. Identify the organs that make up the cardiovascular system. 3. Identify the structures that make up the heart and briefly explain the function of each.

3 Lesson Objectives Upon completion of this lesson, students should be able to: 4. Explain the conduction system of the heart. 5. Explain the functions of the arteries, veins, and capillaries.

4 Overview of the Cardiovascular System Cardiovascular system consists of: Heart Responsible for movement of blood through cardiovascular system throughout entire body, providing oxygen and removing waste Vessels Blood

5 FIGURE 27-1 Location of the heart in the chest cavity.

6 Overview of the Cardiovascular System The Heart Four-chambered muscular pump About size of a fist Weighs approximately 9 ounces Cone shaped, with apex at most inferior point Consists of three linings (layers)

7 Critical Thinking Question 1. What is meant by endocarditis, myocarditis, and pericarditis?

8 Overview of the Cardiovascular System The Heart Pericardium Outer lining; covers heart and large blood vessels attached to it Myocardium Middle layer, or heart muscle; thickest layer

9 Overview of the Cardiovascular System The Heart Endocardium Innermost lining; thin and smooth; contains part of electrical conduction system of heart

10 FIGURE 27-2 Linings of the heart.

11 Overview of the Cardiovascular System The Heart Septum Wall that separates left and right sides of heart Right side moves blood from body to lungs Left side pumps blood back to body

12 Overview of the Cardiovascular System The Heart Two upper chambers (atria) receive blood coming into heart from body or lungs Two lower chambers (ventricles) pump blood out of heart to lungs or body

13 FIGURE 27-3 The heart: interior view of the heart chambers.

14 Overview of the Cardiovascular System Blood Flow Through the Heart Pumping action of heart occurs with contraction of cardiac muscle Superior vena cava vein brings blood from head and upper chest Inferior vena cava vein brings blood from below heart

15 Overview of the Cardiovascular System Blood Flow Through the Heart Right atrium receives blood delivered to heart from body via superior and inferior vena cava From right atrium, heart pumps blood through a valve into right ventricle

16 Overview of the Cardiovascular System Blood Flow Through the Heart Tricuspid valve connects right atrium to right ventricle Right ventricle pumps blood out through pulmonary valve into pulmonary artery, which carries blood to lungs

17 Overview of the Cardiovascular System Blood Flow Through the Heart Blood that enters right atrium and then right ventricle is deoxygenated blood When right ventricle pumps this blood to lungs, there is a gas exchange Blood passes off its carbon dioxide into alveoli of lungs and then it is exhaled from the body

18 Overview of the Cardiovascular System Blood Flow Through the Heart Blood takes on oxygen from air that has been breathed into the same air sacs of the lungs Blood that returns to heart from lungs is now oxygenated blood

19 Overview of the Cardiovascular System Blood Flow Through the Heart Pulmonary vein carries oxygenated blood from lungs; empties it into left atrium of heart Blood leaves left atrium through bicuspid valve

20 Overview of the Cardiovascular System Blood Flow Through the Heart Blood enters left ventricle, which pumps oxygenated blood out from heart to the body Blood leaves left ventricle through aortic valve and enters aorta (largest artery in body) Blood journeys through arteries that branch off from aorta to all regions of body

21 FIGURE 27-4 The flow of blood valves of the heart.

22 Overview of the Cardiovascular System Blood Flow Through the Heart Heart valves function as gateways, never allowing blood to flow backward Damaged or diseased valve can allow blood to escape and flow backward through valve (heart murmur) Sound murmur makes is known as a bruit

23 FIGURE 27-5 The valves of the heart.

24 Critical Thinking Question 1. What happens when the coronary arteries get blocked?

25 Overview of the Cardiovascular System Vascular System of the Heart Coronary arteries supply oxygenated blood to heart After nourishing heart muscle, deoxygenated blood drained into coronary sinus by coronary veins and then back into right atrium for oxygenation Occlusion deprives heart muscle of oxygen, causing chest pain

26 FIGURE 27-6 Coronary circulation: (A) coronary vessels portraying the complexity and extent of the coronary circulation; (B) coronary vessels that supply the anterior surfaces of the heart.

27 Overview of the Cardiovascular System Vascular System of the Heart Permanent damage to heart tissue can occur if cardiac muscle deprived of oxygen for long period of time Ischemia Lack of blood flow to heart Myocardial infarction (MI) Death of heart muscle

28 Overview of the Cardiovascular System Vascular System of the Heart Cardiac arrest Occlusion in heart causes heart to stop beating (pumping blood) Hypoxia Lack of oxygen to tissues caused by ischemia and infarction

29 Overview of the Cardiovascular System Conduction System of the Heart Heart's rate and rhythm controlled by autonomic nervous system Sinoatrial node Atrioventricular node Atrioventricular bundle (Bundle of His)

30 FIGURE 27-7 The conduction system of the heart.

31 Overview of the Cardiovascular System Conduction System of the Heart Sinoatrial (SA) Node Pacemaker of heart Located in upper wall of right atrium Responsible for initiating heartbeat Initiate 60 to 80 beats (contractions) per minute

32 Overview of the Cardiovascular System Conduction System of the Heart Atrioventricular (AV) Node Located under endocardium of right atrium and between atria and ventricles When electrical impulse from SA node reaches this point, AV node delays impulse for fraction of a second to ensure atrium has completely emptied

33 Overview of the Cardiovascular System Conduction System of the Heart Atrioventricular (AV) Node Senses when ventricles have filled Sends an impulse that reaches Bundle of His

34 Overview of the Cardiovascular System Conduction System of the Heart Bundle of His Also known as atrioventricular (AV) bundle Made up of muscle fibers Located in septum of heart Divides into right and left bundle branches Impulse travels from bundle branches into Purkinje fibers

35 Overview of the Cardiovascular System Conduction System of the Heart Purkinje Fibers Specialized conductive fibers Located within walls of ventricles Responsible for relaying cardiac impulses to cells of the ventricles prompting ventricles to contract

36 Overview of the Cardiovascular System The Cardiac Cycle All events that occur during one heartbeat Heart beats about 70 times per minute; can vary from 60 to 110 beats per minute

37 Overview of the Cardiovascular System The Cardiac Cycle Factors that cause heart rate to increase: Exercise Stress Excitement Smoking Rise in body temperature

38 Overview of the Cardiovascular System The Cardiac Cycle Atrial diastole Atrial systole Ventricular diastole Ventricular systole Systole: contraction phase of heart Diastole: relaxation phase of heart

39 FIGURE 27-8 The cardiac cycle showing systole and diastole.

40 Overview of the Cardiovascular System The Cardiac Cycle Heartbeat produces sounds known as "lubdup" sounds as chambers contract and valves close "Lub," heard when ventricles contract and AV valves close "Dup," is sound of ventricles relaxing and semilunar valves closing Ausculation: listening for flow of blood with stethoscope

41 FIGURE 27-9 An overview of the arterial system.

42 Blood Vessels Arteries Vessels that carry blood away from heart High pressure by heartbeat propels blood forward through arteries Elastic tubes that expand with pressure and relax between beats Easy to palpate for pulse and purposes of recording heart rate

43 FIGURE The primary pulse points of the body.

44 Blood Vessels Arteries Radial Brachial Carotid Temporal Femoral Popliteal Dorsalis pedis Anterior tibial

45 Critical Thinking Questions 1. Do all arteries take blood from or to the heart? 2. Do all veins take blood from or to the heart?

46 FIGURE An overview of the veins in venous circulation.

47 Blood Vessels Veins Thin-walled vessels that transport blood to the heart Contain valves that prevent blood from flowing backward

48 Blood Vessels Veins Low pressure is reason why veins need valves to prevent backflow Have elastic walls Venipuncture (phlebotomy): process of removing blood from veins for examination

49 Critical Thinking Question 1. When do veins carry oxygenated blood?

50 Critical Thinking Question 1. How do arteries and veins get many of their names?

51 Blood Vessels Capillaries Microscopic blood vessels Blood offloads oxygen and nutrients to cells and picks up waste material from the cells Blood then transports carbon dioxide and waste material from capillaries to venules Facilitates exchange of gases and nutrients at level of the cells

52 Pulmonary and Systemic Circulation Pulmonary Circulation Route blood takes from heart to lungs via pulmonary artery and back to heart via pulmonary vein Carries deoxygenated blood from right side of heart to lungs and carries oxygenated blood back to left side of heart

53 FIGURE Systemic and pulmonary circulation.

54 Pulmonary and Systemic Circulation Systemic Circulation Delivers oxygenated blood and other nutrients to body cells Carries carbon dioxide and waste products away from cells for elimination from body

55 Critical Thinking Question 1. What are some of the problems that might cause trouble in the cardiovascular system? Be specific.

56 Blood Pressure Force exerted by blood against inner walls of arteries

57 Blood Pressure Continually changes, depending on: Activity Temperature Diet Emotional state Posture Physical condition Medication use

58 Critical Thinking Question 1. Where can you measure the pressure of the blood flow through the heart?

59 Blood Pressure Usually measured in brachial artery with a sphygmomanometer Systolic blood pressure Pressure at highest in arteries during ventricular contraction Diastolic blood pressure When ventricles relax and blood pressure at lowest

60 Blood Pressure Usually measured in brachial artery with a sphygmomanometer Recorded as fraction Systolic blood pressure over diastolic blood pressure Average resting blood pressure for young adult below 120/80

61 Blood Pressure Pulse Pressure Difference between systolic and diastolic blood pressures Normal is 30 to 50 points Indication of tone of arterial walls

62 Critical Thinking Question 1. What kind of patient education or information might you give your patient?

63 Questions?