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Heart outline
• pulmonary & systemic circulation• location of heart in thorax• pericardium• external anatomy of heart• internal anatomy of heart• coronary circulation• CAD, angina and heart attacks• heart valves• conduction system of heart• EKG’s
Fibrous pericardium
Myocardium
Endocardium
Parietal pericardium
Visceral pericardium
Epicardium = visceral pericardium + adipose
cardiomyopathy
Fibrous skeleton: collagen & elastic fibers between chambers & around valves
• structural support • prevents valves from being overly distended• anchors myocardium• electrical “insulator” between atria and ventricles
aorta
Superior vena cava
Inferior vena cava
Right atrium
Right ventricle
Pulmonary artery
Anterior View
PV
LV
LA
Chambers of the Heart
• 4 chambers – 2 upper atria (atria = entry hall) (auricle = little ear)– 2 lower ventricles (ventricles = little bellies)
Auricle
Right ventricle
Pulmonary valve
Tricuspid valve
Trabeculae carneae
Papillary muscle with tendinous cords
Left ventricle
Aortic valve
Mitral (bicuspid) valve
Papillary muscleswith chordae tendineae
Trabeculae carneae
Coronarysinus
Coronary circulation
L & R coronary artery = directly off aorta just distal to aortic valvesCoronary sinus = drains into right atrium
RCA
RCA
LCA (Under auricle)
Fig. 20.12
Coronary artery disease (CAD)• narrowing of coronary arteries• leading cause of death in US
Atherosclerosis• fatty plaque on arterial walls
Myocardial infarction (MI)
• dead tissue areas in myocardium• caused by interruption of blood flow• cardiac muscles cells don’t regenerate• replaced by scar tissue• scarred or ischemic cardiac muscle can’t pump or conduct electrical impulses• arrhythmias (ventricular fibrillation)• Angina pectoris (chest pain)
Referred pain:
Organ & skin pain fibers travel to the spinal cord together
Organ pain misinterpreted as skin pain (referred pain)
Tricuspidvalve
Bicuspid or Mitralvalve
Pulmonary valve(semilunar valve)
Aortic valve(semilunar valve)
Semilunar valves• aortic & pulmonary valves• each has 3 cusps (no tendinous cords)• close when pressure in ventricles falls
Atrioventricular (AV) valves• tricuspid and bicuspid (Mitral)• tricuspid = 3 cusps, bicuspid = 2• connected to papillary muscle via tendinous cords• close when pressure in ventricles increases
Atrioventricular Valves Open
Ventricles = diastoleAtria = systole(atrial pressure > ventricle pressure)
Atrioventricular Valves Close
• Ventricles = systole• Atria = diastole
• Ventricle pressure > atrial pressure
• A-V valves close preventing backflow of blood into atria
1.What are the ventricles doing in A?
2.Is blood flowing into the coronary arteries in A or B?
Valve Function Review
A B
Murmurs – any abnormal heart sound
Stenosis – narrowing of valve orifice• Congenital, rheumatic fever• Mitral most common (aortic)
Insufficiency or regurgitation – incomplete closure of valve• Many causes (MI, RF, HF, prolapse)• Aortic and mitral most common
Prolapse: most common valve disease• CT diseases or genetic
Rheumatic fever - strepA
Conduction System of Heart
SA node – AV node – AV bundle of His (between ventricles) – Purkinje fibers
How does your heart rate change?• Nervous control (ANS)• hormones• drugs
Heart block: electrical signals blockedBundle branch block or total heart block
Ectopic focusArrhythmia: irregular heart beatFibrillations: uncoordinated contractions
• EKG = electrocardiogram– Recording electrical
currents in heart • P wave
– atrial contraction • P to Q interval
– time for impulse to travel from SA node to AV node
• QRS complex – ventricular contraction
• T wave– ventricular relaxation