Heart anatomy


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Dr.Waqas Nawaz
PMAS arid agriculture university rawalpindi

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Heart anatomy

  1. 1. Submitted to:Dr.Zeeshan Akbar Submitted by: Waqas Nawaz 11-arid-975
  2. 2. Heart AnatomyApproximately the size of your fist Wt. = 250-300 gramsLocation In the mediastinum between the lungs Superior surface of diaphragm ⅔’s of it lies to the left of the midsternal line Anterior to the vertebral column, posterior to the sternum
  3. 3. Heart Anatomy Figure 18.1
  4. 4. Coverings of the Heart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 called the pericardial cavity Protects and anchors the heart Prevents overfilling of the heart with blood Allows for the heart to work in a relatively friction-free environment
  5. 5. Pericardial Layers of the Heart Figure 18.2
  6. 6. Layers of the Heart WallEpicardium – visceral pericardiumMyocardium – cardiac muscle layer forming the bulk of the heartEndocardium – endothelial layer of the inner myocardial surface
  7. 7. Heart AnatomyExternal markings Apex - pointed inferior region Base - upper region Coronary sulcus  Indentation that separates atria from ventricles Anterior and posterior interventricular sulcus  Separates right and left ventriclesInternal divisions Atria (superior) and ventricles (inferior) Interventricular and interatrial septa
  8. 8. Atria of the HeartAtria - receiving chambers of the heart Receive venous blood returning to heart Separated by an interatrial septum (wall)  Foramen ovale - opening in interatrial septum in fetus  Fossa ovalis - remnant of foramen ovaleEach atrium has a protruding auriclePectinate muscles mark atrial wallsPump blood into ventriclesBlood enters right atria from superior and inferior venae cavae and coronary sinusBlood enters left atria from pulmonary veins
  9. 9. Gross Anatomy of Heart: FrontalSection Figure 18.4e
  10. 10. Ventricles of the HeartVentricles are the discharging chambers of the heartPapillary muscles and trabeculae carneae muscles mark ventricular wallsSeparated by an interventricular septum Contains components of the conduction systemRight ventricle pumps blood into the pulmonary trunkLeft ventricle pumps blood into the aorta Thicker myocardium due to greater work load  Pulmonary circulation supplied by right ventricle is a much low pressure system requiring less energy output by ventricle  Systemic circulation supplied by left ventricle is a higher pressure system and thus requires more forceful contractions
  11. 11. External Heart: Anterior View Figure 18.4b
  12. 12. Structure of Heart WallLeft ventricle – three times thicker than right Exerts more pumping force Flattens right ventricle into a crescent shape Figure 18.7
  13. 13. Heart ValvesHeart valves ensure unidirectional blood flow through the heart  Composed of an endocardium with a connective tissue coreTwo major types Atrioventricular valves Semilunar valvesAtrioventricular (AV) valves lie between the atria and the ventricles R-AV valve = tricuspid valve L-AV valve = bicuspid or mitral valveAV valves prevent backflow of blood into the atria when ventricles contractChordae tendineae anchor AV valves to papillary muscles of ventricle wall Prevent prolapse of valve back into atrium
  14. 14. Semilunar Heart ValvesSemilunar valves prevent backflow of blood into the ventriclesHave no chordae tendinae attachmentsAortic semilunar valve lies between the left ventricle and the aortaPulmonary semilunar valve lies between the right ventricle and pulmonary trunkHeart sounds (“lub-dup”) due to valves closing “Lub” - closing of atrioventricular valves “Dub”- closing of semilunar valves
  15. 15. Fibrous SkeletonSurrounds all four valves Composed of dense connective tissueFunctions Anchors valve cusps Prevents overdilation of valve openings Main point of insertion for cardiac muscle Blocks direct spread of electrical impulses
  16. 16. Heart Valves
  17. 17. Conducting SystemCardiac muscle tissue has intrinsic ability to: Generate and conduct impulses Signal these cells to contract rhythmicallyConducting system A series of specialized cardiac muscle cells Sinoatrial (SA) node sets the inherent rate of contraction
  18. 18. Conducting System
  19. 19. Innervation Heart rate is altered by external controls Nerves to the heart include: Visceral sensory fibers Parasympathetic branches of the vagus nerve Sympathetic fibers – from cervical and upper thoracic chain ganglia
  20. 20. External Heart: Posterior View Figure 18.4d
  21. 21. Major Vessels of the HeartVessels returning blood to the heart include: Superior and inferior venae cavae  Open into the right atrium  Return deoxygenated blood from body cells Coronary sinus  Opens into the right atrium  Returns deoxygenated blood from heart muscle (coronary veins) Right and left pulmonary veins  Open into the left atrium  Return oxygenated blood from lungs
  22. 22. Major Vessels of the HeartVessels conveying blood away from the heart include: Pulmonary trunk  Carries deoxygenated blood from right ventricle to lungs  Splits into right and left pulmonary arteries Ascending aorta  Carries oxygenated blood away from left atrium to body organs  Three major branches  Brachiocephalic  Left common carotid,  Left subclavian artery
  23. 23. Blood Flow Through the Heart Figure 18.6
  24. 24. Pathway of Blood Through the Heart and Lungs Figure 18.5
  25. 25. Coronary CirculationCoronary circulation The functional blood supply to the heart muscle itself R and L Coronary arteries are 1st branches off the ascending aorta Coronary sinus (vein) empties into R. atriumCollateral routes ensure blood delivery to heart even if major vessels are occluded
  26. 26. Coronary Circulation - ArteriesRight Coronary Artery  Supplies blood to  Right atrium and posterior surface of both ventricles  Branches into the  Marginal artery - extends across surface of R. ventricle  Posterior interventricular artery  Found in posterior interventricular sulcusLeft Coronary Artery  Supplies blood to  Left atrium and left ventricle  Branches into  Circumflex artery  Anterior interventricular artery  Found in anterior interventricular sulcus  Connected with posterior interventricular artery via arterial anastomoses
  27. 27. Coronary Circulation: Arterial Supply Figure 18.7a
  28. 28. Coronary Circulation - VeinsCoronary sinus - Vein that empties into right atrium Receives deoxygenated blood from:  Great cardiac vein - on anterior surface  Posterior cardiac vein  Drains area served by circumflex  Middle cardiac vein  Drains area served by posterior interventricular artery  Small cardiac vein  Drains blood from posterior surfaces of right atrium and ventricle
  29. 29. Coronary Circulation: Venous Supply Figure 18.7b
  30. 30. Microscopic Anatomy of HeartMuscle muscle cellsCardiac Short, striated, branched, and interconnected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Many mitochondria (25% of total volume)
  31. 31. Microscopic Anatomy of HeartMuscle Figure 18.11
  32. 32. Disorders of the HeartCoronary artery disease Atherosclerosis – fatty deposits Arteriosclerosis - hardening of the arteries Angina pectoris – chest pain Myocardial infarction – blocked coronary artery Silent ischemia – no pain or warning Fibrillation - irregular heart beat; may occur in either atria or ventricles