Cardiovascular Disorders

1.Cardiovascular Disorders
Chapter 10

2. 18
The Cardiovascular System: The Heart
DR Jones
Part A
3. Heart Anatomy
Approximately the size of your fist
Location
Superior surface of diaphragm
Left of the midline
Anterior to the vertebral column, posterior to the sternum
4. Heart Anatomy
Figure 18.1
5. Coverings of the Heart: Anatomy
Pericardium a double-walled sac around the heart composed of:
A superficial fibrous pericardium
A deep two-layer serous pericardium
The parietal layer lines the internal surface of the fibrous pericardium
The visceral layer or epicardium lines the surface of the heart
They are separated by the fluid-filled pericardial cavity
6. Coverings of the Heart: Physiology
The pericardium:
Protects and anchors the heart
Allows for the heart to work in a relatively friction-free environment
7. Pericardial Layers of the Heart
Figure 18.2
8. Heart Wall
Epicardium visceral layer of the serous pericardium
Myocardium cardiac muscle layer forming the bulk of the heart
Fibrous skeleton of the heart crisscrossing, interlacing layer of connective tissue
Endocardium endothelial layer of the inner myocardial surface
9. External Heart: Major Vessels of the Heart
Vessels returning blood to the heart include:
Superior and inferior venae cavae
Right and left pulmonary veins
Vessels conveying blood away from the heart include:
Pulmonary trunk, which splits into right and left pulmonary arteries
Ascending aorta (three branches) brachiocephalic, left common carotid, and subclavian arteries
10. Arteries right and left coronary (in atrioventricular groove), marginal, circumflex, and anterior interventricular arteries
Veins small cardiac, anterior cardiac, and great cardiac veins
External Heart: Vessels that Supply/Drain the Heart
11. External Heart: Anterior View
Figure 18.4b
12. External Heart: Major Vessels of the Heart
Vessels returning blood to the heart include:
Right and left pulmonary veins
Superior and inferior venae cavae
Vessels conveying blood away from the heart include:
Aorta
Right and left pulmonary arteries
13. Arteries right coronary artery (in atrioventricular groove) and the posterior interventricular artery (in interventricular groove)
Veins great cardiac vein, posterior vein to left ventricle, coronary sinus, and middle cardiac vein
External Heart: Vessels that Supply/Drain the Heart
14. External Heart: Posterior View
Figure 18.4d
15. Gross Anatomy of Heart: Frontal Section
Figure 18.4e
16. Atria of the Heart
Atria are the receiving chambers of the heart
Each atrium has a protruding auricle
Pectinate muscles mark atrial walls
Blood enters right atria from superior and inferior venae cavae and coronary sinus
Blood enters left atria from pulmonary veins
17. Ventricles of the Heart
Ventricles are the discharging chambers of the heart
Papillary muscles and trabeculae carneae muscles mark ventricular walls
Right ventricle pumps blood into the pulmonary trunk
Left ventricle pumps blood into the aorta
18. Pathway of Blood Through the Heart and Lungs
Right atrium tricuspid valve right ventricle
Right ventricle pulmonary semilunar valve pulmonary arteries lungs
Lungs pulmonary veins left atrium
Left atrium bicuspid valve left ventricle
Left ventricle aortic semilunar valve aorta
Aorta systemic circulation
19. Heart Valves
Figure 18.8a, b
20. Heart Valves
Figure 18.8c, d
21. Atrioventricular Valve Function
Figure 18.9
22. Semilunar Valve Function
Figure 18.10
23. Heart Valves
Heart valves ensure unidirectional blood flow through the heart
Atrioventricular (AV) valves lie between the atria and the ventricles
AV valves prevent backflow into the atria when ventricles contract
Chordae tendineae anchor AV valves to papillary muscles
24. Heart Valves
Aortic semilunar valve lies between the left ventricle and the aorta
Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk
Semilunar valves prevent backflow of blood into the ventricles
25. Coronary Circulation
Coronary circulation is the functional blood supply to the heart muscle itself
Collateral routes ensure blood delivery to heart even if major vessels are occluded
26. Coronary Circulation: Arterial Supply
Figure 18.7a
27. Coronary Circulation: Venous Supply
Figure 18.7b
28. 29. Microscopic Anatomy of Heart Muscle
Cardiac muscle is striated, short, fat, branched, and interconnected TQ
The connective tissue endomysium acts as both tendon and insertion
Intercalated discs anchor cardiac cells together and allow free passage of ions
Heart muscle behaves as a functional syncytium
PLAY
InterActive Physiology: Cardiovascular System: Anatomy Review: The Heart
30. Microscopic Anatomy of Heart Muscle
Figure 18.11
31. Cardiac Muscle Contraction
Heart muscle:
Is stimulated by nerves and is self-excitable (automaticity)
Contracts as a unit
Has a long (250 ms) absolute refractory period
Cardiac muscle contraction is similar to skeletal muscle contraction
32. Heart Physiology: Intrinsic Conduction System
Autorhythmic cells:
Initiate action potentials
Have unstable resting potentials called pacemaker potentials
Use calcium influx (rather than sodium) for rising phase of the action potential (prolonging contracture)
33. Pacemaker and Action Potentials of the Heart
Figure 18.13
34. Calcium Channels.
In cardiac myocytesL type Ca channels open when the plasma membrane is depolarized by an action potential carried along the muscle cells by the opening of voltage gated sodium channels. This action potenial is terminated and its duration determined by the opening of K channels. Ca influx triggers massive release of Ca from intracellularstores by opening the ryanodine sensitive Ca channels in the sarcoplasmic reticulum resulting in an intracellular Ca transient. Ca influx and released Ca directly initiate contraction.Contraction is terminated by the rapid uptake into the SR by SR Ca ATPases (SERCA)
35. CA++ channel blockers
36. Heart Physiology: Sequence of Excitation
Figure 18.14a
Sinoatrial (SA) node generates impulses about 75 times/minute
Atrioventricular (AV) node delays the impulse approximately 0.1 second
Impulse passes from atria to ventricles via the atrioventricular bundle (bundle of His)
AV bundle splits into two pathways in the interventricular septum (bundle branches)
Bundle branches carry the impulse toward the apex of the heart
Purkinje fibers carry the impulse to the heart apex and ventricular walls
39. Heart Excitation Related to ECG
Figure 18.17
40. Extrinsic Innervation of the Heart
Heart is stimulated by the sympathetic cardioacceleratory center
Heart is inhibited by the parasympathetic cardioinhibitory center
Figure 18.15
41. Electrocardiography
Electrical activity is recorded by electrocardiogram (ECG)
P wave corresponds to Depolarization of the atria!!!!
QRS complex corresponds to ventricular depolarization
T wave corresponds to ventricular repolarization
Atrial repolarization record is masked by the larger QRS complex
PLAY
InterActive Physiology: Cardiovascular System: Intrinsic Conduction System
42. Electrocardiography
Figure 18.16
43. Link for Dr Dubins book..
http://www.emergencyekg.com
44. 45. 46. 47. 48. Cardiac Cycle
49. Cardiac Cycle
50. Cardiac Cycle
Cardiac cycle refers to all events associated with blood flow through the heart
Systole contraction of heart muscle
Diastole relaxation of heart muscle
51. Phases of the Cardiac Cycle
Ventricular filling mid-to-late diastole
Heart blood pressure is low as blood enters atria and flows into ventricles
AV valves are open, then atrial systole occurs
Ventricular systole
Atria relax
Rising ventricular pressure results in closing of AV valves(1)
Isovolumetric contraction phase(2)
Ventricular ejection phase opens semilunar valves(3)
Isovolumetric relaxation early diastole
Ventricles relax
Backflow of blood in aorta and pulmonary trunk closes semilunar valves
Dicrotic notch brief rise in aortic pressure caused by backflow of blood rebounding off semilunar valves
InterActive Physiology: Cardiovascular System: Cardiac Cycle
PLAY
54. Figure 18.20
55. Cardiac Output (CO) and Reserve
CO is the amount of blood pumped by each ventricle in one minute
CO is the product of heart rate (HR) and stroke volume (SV)
HR is the number of heart beats per minute
SV is the amount of blood pumped out by a ventricle with each beat (or stroke)
Cardiac reserve is the difference between resting and maximal CO
56. Stroke Volume
57. Regulation of Stroke Volume
SV = end diastolic volume (EDV) minus end systolic volume (ESV)
EDV = amount of blood collected in a ventricle during diastole
ESV = amount of blood remaining in a ventricle after contraction
58. Factors Affecting Stroke Volume
Preload amount ventricles are stretched by contained blood
Contractility cardiac cell contractile force due to factors other than EDV
Afterload back pressure exerted by blood in the large arteries leaving the heart
59. Frank-Starling Law of the Heart
Preload, or degree of stretch, of cardiac muscle cells before they contract is the critical factor controlling stroke volume
Slow heartbeat and exercise increase venous return to the heart, increasing SV
Blood loss and extremely rapid heartbeat decrease SV
60. Preload and Afterload
Figure 18.21
61. Extrinsic Factors Influencing Stroke Volume
Contractility is the increase in contractile strength, independent of stretch and EDV
Increase in contractility comes from:
Increased sympathetic stimuli
Certain hormones
Ca2+ and some drugs
62. Extrinsic Factors Influencing Stroke Volume
Agents/factors that decrease contractility include:
Acidosis
Increased extracellular K+
Calcium channel blockers
63. Contractility and Norepinephrine
Sympathetic stimulation releases norepinephrine and initiates a cyclic AMP second-messenger system
Figure 18.22
64. Regulation of Heart Rate
Positive chronotropic factors increase heart rate
Negative chronotropic factors decrease heart rate
65. Regulation of Heart Rate: Autonomic Nervous System
Sympathetic nervous system (SNS) stimulation is activated by stress, anxiety, excitement, or exercise
Parasympathetic nervous system (PNS) stimulation is mediated by acetylcholine and opposes the SNS
PNS dominates the autonomic stimulation, slowing heart rate and causing vagal tone
66. Atrial (Bainbridge) Reflex
Atrial (Bainbridge) reflex a sympathetic reflex initiated by increased blood in the atria
Causes stimulation of the SA node
Stimulates baroreceptors in the atria, causing increased SNS stimulation
67. Chemical Regulation of the Heart
The hormones epinephrine and thyroxine increase heart rate
Intra- and extracellular ion concentrations must be maintained for normal heart function
InterActive Physiology: Cardiovascular System: Cardiac Output
PLAY
68. 69. Arrhythmias
Bradycardia
AV delays and blocks
Tachyarrhythmias
Fibrillation
Flutter
70. Congestive Failure
Inadequate pump function
pump failure
R Lboth and how fast it develops
71. Left Ventricular Failure
Not pumping to the bodybacks up in lungs
Dyspnea,orthopnea,pnd, hemoptysis,occ chest pain, fatique
HR up Resp rate Up
Rales
Etiology: Table 10-1
72. Pathophysiology of Left Ventricular Failure
Hemodynamic changes- systolic dyfunction with decreased stroke volume
Diastolic dysfunction- dilitation of atrium and backup of pressure into lungs
Neurohumoral changesRenin angiotensin as a result of percieved decreased cardiac output Elevated levels of norepinephrineVasopressin release (adh) Cytokine release and Tumor Necrosis Factor and Endothelin
73. Left Heart Pphys ,continued.
Ca uptake is slowed by sarcoplasmic reticulum
Alpha one receptors upregulate and increase in number
74. Right Ventricular Failure
SOBpedal edema and abdominal discomfort and pain
Causesame as LV disfunction plus pulmonary hypertension or L-R shunt with increased pressure on the right ventricle
Elevated Jugular pressure
75. Signs and symptoms of Rt heart failure
Anasarca- generalized edema
Ascites peritoneal accumulation of fluid
Pedal edema
Hepatojugular Reflux-pressure on the liver for 5 seconds gives increased volume to RA and backs up in Jugular vein in neck
Abd pain- liver distentension
76. Valvular Heart Disease
Stenosis or Regurgitation
Rare to be found on the right side
We will concentrate on Left side valves
Aortic and Mitral valves
Murmur what is it
When and what they sound like tells you what is going on
77. Aortic Stenosis
78. Aortic Stenosis
Congenital AS is usually asymptomatic until at least age 10 or 20 yr, when symptoms may begin to develop insidiously.
exertional syncope, angina, and dyspnea
Murmur
IHSS
79. Aortic Regurgitation
80. Aortic Regurgitation
Acute or Chronic
Develops into L sided failure
Acute: SOB, pulmonary edema, hypotension, develop quickly
Increased volume load on the left ventricle eccentric hypertrophy
Wide pulse pressures
81. Mitral Stenosis
82. Mitral Stenosis
Mitral stenosis (MS), causes an obstruction in blood flow from the left atrium to left ventricle. There is therefore an increase in pressure within the left atrium, pulmonary vasculature, and right side of the heart, while the left ventricle is unaffected in pure MS
major cause of MS is rheumatic fever
Dyspnea , Fatigue and hemoptysis
83. Mitral Stenosis
increase in pulmonary venous, capillary and arterial pressures and resistance.
With mild to moderate mitral stenosis, these abnormalities are often only apparent with exercise or other conditions that increase heart rate; they eventually are seen at rest as the severity of the stenosis increases
In addition to exercise, the onset of atrial fibrillation can also lead to clinical decompensation.
84. Mitral Regurgitation
For many years, rheumatic fever was the predominant cause of mitral regurgitation. Now, the major etiologies are mitral valve prolapse and coronary disease
exercise intolerance, dyspnea, or fatigue
Compensated and uncompensated
Pulmonary hypertension along with other changes in the ventricle
ATRIAL ENLARGEMENT AND FIBRILLATION Chronic MR is often complicated by the development of left atrial enlargement and atrial fibrillation (AF), both of which may have an impact on patient outcome
Objective measures of LV size and function The severity of MR can be assessed semiquantitatively by Doppler echocardiography or angiography
85. 86. Coronary Artery disease
87. 88. 89. Coronary Artery Disease
Chest Pain, SOB, Shock (cardiogenic), Bradycardia, Nausea and Vomiting, Tachycardia
EKG CHANGES of Ischemia
Enzyme changesreleased from the myocardial damaged cells
90. Pericardial Diseases
The pain is usually sharp and stabbing.
can arise slowly or suddenly and can radiate directly to the back, to the neck or to the arm.
pain can radiate to the shoulder blade
pain can be made worse with deep breaths (pleuritic).
pain is frequently positional and made worse when lying flat and better when leaning forward.
91. Pericarditis
Friction Rub
May also have pleural effusion
Tamponade is to be avoided
AOB
Elevated Jugular pressure
Hypotension
Paradoxic Pulse and muffled heart sounds
92. Figure 18.25
Examples of Congenital Heart Defects
93. Developmental Aspects of the Heart
Fetal heart structures that bypass pulmonary circulation
Foramen ovale connects the two atria
Ductus arteriosus connects pulmonary trunk and the aorta

Documents

Cardiovascular Disorders