Chapter 5 Part 2 Heart Anatomy PDF

Chapter 5: Part 2 © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Heart Hollow, four- chambered, muscular organ Consists of upper- right...

Chapter 5: Part 2 © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Heart Hollow, four- chambered, muscular organ Consists of upper- right and left atria and lower-right and left ventricles © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Heart Anterior and posterior views hollow, 4, muscle, cone- shape, 250 – 350 g, in mediastinum, 2nd – 5th intercostal space, superior surface of diaphragm, anterior to spine, posterior to sternum -2/3 – left via midsternal line -atria (interartrial septum), small, thin wall, contribute little to pump -ventricle (interventricular septum) -2 separate pumps: rt vs. left - base: 9 cm, toward rt shoulder - Apex: inferior to left hip - PMI – apex 5th & 6th rib, left nipple © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-2. Anterior View of Heart © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-2. PMI & Midsternal Line © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Posterior View of Heart © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-2. Relationship of Heart to Other Body Parts Relationship of heart to sternum, ribs, and diaphragm Cross-sectional view showing relationship of heart to thorax Relationship of heart to lung’s great vessels © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-3.  Pericardium Double-walled sac in which heart is enclosed Outer wall (fibrous pericardium) is tough, dense, connective tissue layer – Primary functions: 1. Protect heart 2. Anchor heart to surrounding structures 1. E.g., diaphragm, great vessels 3. Prevent heart from overfilling © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Walls of the Heart Composed of three layers: Heart Walls; 1) Epicardium-(squamous epithelial) older = fat 2) myocardium – thick, bulk of ♥, cross-striations (spiral or circular bundles) = fibrous skeleton of the ♥, conduction 3) Endocardium - white sheet of squamous. Inner, chambers, blood vessels, continous w/ vena cava ♥ enclosed in double-wall sac -outer: protect & anchor to surround structures: diaphragm & great blood vessles, prevent overfilling -serous: thin, slippery, serous membrane, lines outer layer © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Layers of the Pericardium and Heart Wall © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-5.  Cardiac Muscle Bundles View of spiral and circular arrangement of cardiac muscle bundles Which layer? © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-6.  Blood Supply of the Heart Originates directly from aorta by means of two arteries – Left coronary artery – Right coronary artery Left coronary artery divides into: – Circumflex branch – Anterior interventricular branch © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Blood Supply of the Heart Venous system of heart parallels coronary arteries – Venous blood from anterior side of heart empties into great cardiac veins – Venous blood from posterior portion of heart is collected by middle cardiac vein – Both 1) Great and 2) Middle Cardiac Veins empty into Right atrium via coronary sinus. – 3) Thebesian veins (cardiac muscle) Empty into: 1. Right Atrium 2. Left atrium (shunt) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Both 1) Great and 2) Middle Cardiac Veins empty into Right atrium via coronary sinus. © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. 3) Thebesian veins (cardiac muscle) Empty into: Right Atrium & Left atrium (shunt) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Internal Chambers and Valves of the Heart – Blood Flow © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-9. Vascular network of circulatory system composed of two major subdivisions: 1) Systemic system 2) Pulmonary system Both systems composed of: Arteries Arterioles Capillaries Venules Veins © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-10. Neural Control of the Vascular System Pulmonary arterioles and most arterioles in systemic circulation controlled by sympathetic impulses Sympathetic fibers found in arteries, arterioles, and, to lesser degree, veins Vasomotor center & cardiac center – medulla oblongata Normal – continous – vasomotor tone (except – arterioles of ♥, brain, & skeletal muscles – vasodilation) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Neural Control and the Vascular System Sympathetic neural fibers to arterioles are especially abundant arterioles (resistance vessels) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-11.  Baroreceptor Reflex Specialized stretch In carotid arteries, receptors called baroreceptors found in carotid baroreceptors located in sinuses located high in neck walls of carotid arteries where common carotid arteries and aorta divide into external and internal – Also known as carotid arteries pressoreceptors carotid – 9th nerve Baroreceptors regulate In aorta, baroreceptors located arterial blood pressure by in aortic arch initiating reflex aorta – 10th nerve adjustments to changes Short term regulators –BP in blood pressure adjust almost instantly long term – reset (BP) to new level © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Location of the Arterial Baroreceptors © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-12.  Arterial Blood Pressure When arterial blood pressure decreases, baroreceptor reflex causes the following to increase: – Heart rate – Myocardial force of contraction – Arterial constriction – Venous constriction Net Result – Increased cardiac output CO = HR x SV – Increase in total peripheral resistance – Return of blood pressure to normal © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Types of Pressures Used to Study Blood Flow Three different types of pressures used to study blood flow: 1. Intravascular (intraluminal) pressure Actual blood pressure in lumen of any vessel at any point relative to barometric pressure 2. Transmural pressure 3. Driving pressue Pressure difference between pressure at one point in vessel and pressure at any other point downstream in vessel © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Transmural Pressure Difference between intravascular pressure of vessel and pressure surrounding vessel Positive when pressure inside vessel exceeds pressure outside vessel Negative when pressure inside vessel is less than pressure surrounding vessel Pi – Po © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Types of Blood Pressures Used to Study Blood Flow © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-14.  Sequence of Cardiac Contraction Systolic pressure – Maximum pressure generated during ventricular contraction Diastolic pressure – Lowest pressure that remains in arteries prior to next ventricular contraction (relaxation) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Sequence of Cardiac Contraction A. Ventricular diastole and atrial systole B. Ventricular systole and atrial diastole © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-15.  Sequence of Cardiac Contraction Systemic system Pulmonary system – Normal systolic pressure – Normal systolic pressure is approximately 120 is approximately 25 mmHg mmHg – Normal diastolic – Normal diastolic pressure is pressure is approximately 80 mmHg approximately 8 mmHg – 120/80 – 25/8 © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Systemic Circulation Summary of diastolic and systolic pressures in various segments of circulatory system Red vessels – Oxygenated blood Blue vessels – Deoxygenated blood © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-16. Mean Arterial Blood Pressure (MAP) MAP can be estimated by measuring systolic blood pressure (SBP) and diastolic blood pressure (DBP) and using the following formula: © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  MAP For example, mean MAP = SBP + (2 x DBP) arterial blood 3 pressure of systemic = 120 + (2 x 80) system, which has 3 SBP of 120 mmHg = 280 and DBP of 80 mmHg, would be 3 calculated as follows: = 93 mmHg © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  MAP & Driving Pressure Systemic MAP = 80 – 100, < 60 = brain & kidney – organ deterioration & failure Pulmonary art – 15, left at = 5, driving pressure? Vs. Systemic vs Pulmonary Aorta MAP: 100 mmHg RAP = 2 mmHg driving pressure? Compare these 2 systems © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Normal Values CVP: 2 to 6 (4 to 12) mmHg Right Ventricle: 25/0 PAP: 25 / 8 (Sys/Dia) – Systolic 20 to 30 – Diastolic 5 to 15 PWP: 4 to 12 Left Atrium: 2 to 6 Left Ventricle: 120 / 0 © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Major Arterial Pulse Sites © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-18.  Blood Volume and Its Effect on Blood Pressure Stroke volume -40 – 80 ml Cardiac output – 5L (4 to 8) Blood volume –5L – 75% - systemic (60% veins, 10% arteries) – 15% - ♥ – 10% - pulmonary (capillary bed – 75 – 200ml) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Cardiac Output (CO) Calculated by multiplying stroke volume (SV) by heart rate (HR) 4 to 8 L/min © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Example If stroke volume is 70 mL, and heart rate is 72 beats per minute (bpm), cardiac output is: © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Cardiac Output and Blood Pressure Cardiac output directly influences blood pressure Cardiac Output = Stroke Volume x HR CO = SV x HR QT = SV x HR – When either SV or HR increase, blood pressure increases – When either SV or HR decrease, blood pressure decreases © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Distribution of Pulmonary Blood Flow In upright lung, blood flow steadily increases from apex to base (30 cm) Apex - > 15 cm H20 -intraluminal pressures- greater where? Poiseuille’s law (V=Pr) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-19. Distribution of Pulmonary Blood Flow Linear distribution is function of: 1. Gravity 2. Cardiac output 3. Pulmonary vascular resistance © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  1.Gravity Because blood is relatively heavy substance, it is gravity-dependent Blood naturally moves to portion of body, or portion of organ, closest to ground © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Distribution of Pulmonary Blood Flow Blood flow normally moves into gravity- dependent areas of lungs A. Erect B. Supine C. Lateral D. Upside-down © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-20.  2. Determinants of Cardiac Output 1. Myocardial contractility 2. Ventricular preload 3. Ventricular afterload © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Myocardial Contractility Regarded as force generated by myocardium when ventricular muscle fibers shorten In general, when contractility of heart increases or decreases: – Cardiac output increases or decreases respectively No single measurement – pulse, BP, skin temp, serial hemodynamics © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Myocardial Contractility Positive inotropism – Increase in myocardial contractility Negative inotropism – Decrease in myocardial contractility © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Ventricular Preload Degree to which myocardial fiber is stretched prior to contraction (end-diastole) Reflected in: – Ventricular end-diastolic pressure (VEDP) Which, in essence, reflects: – Ventricular end-diastolic volume (VEDV) – VEDV and VEDP are directly proportional with cardiac output Within limits, the more myocardial fiber is stretched during diastole (preload), the more strongly it will contract during systole – Results in greater myocardial contractility © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Ventricular Afterload Force against which Directly influenced by: ventricles must work – Volume and viscosity to pump blood of blood ejected Best reflected by – Peripheral vascular arterial systolic blood resistance pressure – Total cross-sectional areas of vascular space into which blood is ejected © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Ventricular Afterload Blood pressure (BP) is function of CO times systemic vascular resistance (SVR) Note, can change (rewrite) formula – CO = BP / SVR Or – SVR = BP / CO © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Vascular Resistance Circulatory resistance In general, when approximated by vascular resistance dividing MAP by CO increases: – Blood pressure increases Results in increased ventricular afterload Note in previous slide – SVR = BP / CO © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Active Mechanisms: Vascular Constriction Vascular Dilation (↑ Resistance) (↓ Resistance) Abnormal blood gases Pharmacologic – ↓ PO2 stimulation Hypoxia – Oxygen – ↑ PCO2 – Isoproterenol Hypercapnia – Aminophylline – ↓ pH – Calcium-channel blocking Acidemia © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Passive Mechanisms: Vascular Constriction (↑ Resistance) ↑ Lung volume (extreme) ↓ Lung volume 2 groups: Alveolar vessel (pul capillaries) Extra-alveolar vessels © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Vessels During Inspiration Resistance Increases at both high and low lung volumes © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-25. Pulmonary Vascular Resistance Lowest near FRC Increases at both high and low lung volumes © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-27. Pulmonary Vascular Resistance Schematic drawing of extra-alveolar “corner vessels” found at junction of alveolar septa © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Figure 5-26. Passive Mechanisms: Vascular Dilation (↓ Resistance) ↑ Blood volume - recruitment & distention decrease pulmonary vascular resistance © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Passive Mechanisms: Vascular Constriction (↑ Resistance) ↑ Blood viscosity - Hct, integrity of RBC, & plasma composition – E.g. Polycythemia with Hct 55 to 60% Due to chronic low arterial blood 02 levels or hypoxemia. – Digital clubbing © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Effects of Active and Passive Mechanisms on Vascular Resistance © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Table 5-4.  Effects of Active and Passive Mechanisms on Vascular Resistance © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Table 5-4.  Formulas & Normal Values Systemic Blood CVP: 2 to 6 (4 to 12) Pressure mmHg – 120/80 mmHg Right Ventricle: 25/0 Pulmonary Blood PAP: 25 / 8 (Sys/Dia) Pressure Systolic 20 to 30 – 25/8 mmHg Diastolic 5 to 15 Mean Arterial Blood PWP: 4 to 12 Pressure (MAP) Left Atrium: 2 to 6 – MAP = [SBP + 2(DBP)] / 3 Left Ventricle: 120 / 0 © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  Formulas & Normal Values Cardiac Output (CO or Vascular Resistance QT) – Resistance = MAP / CO – 4 to 8 Lpm Systemic Vascular – CO = SV x HR Resistance – QT = SV x HR – SVR = BP / CO – CO = BP / SVR Blood Pressure – BP = CO x SVR SV = 40 to 80 ml / beat © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.  References Des Jardins, T. (2018). Cardiopulmonary Anatomy & Physiology: Essentials for Respiratory Care (7th ed.). Boston, MA: Cengage Des Jardins, T. (2012). Cardiopulmonary Anatomy & Physiology: Essentials for Respiratory Care (6th ed.). Canada: Thomson Delmar Learning Wilkins, R. L., Stoller, J. K., & Kacmarek, R. M. (2009). Egan's Fundamentals of Respiratory Care (9th Edition ed.). St. Louis, MO: Mosby, Inc. © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.