Heart Anatomy Vid 2 Part 1

Pericardium and Heart Wall

  • Pericardium layers: fibrous pericardium (outer), parietal pericardium, visceral pericardium (epicardium).

  • Heart wall layers: epicardium, myocardium, endocardium.

  • Epicardium = visceral layer of serous pericardium; fibrous pericardium provides outer support.

Cardiac Skeleton and Valve Attachments

  • Cardiac skeleton = dense connective tissue creating four fibrous rings around the valves

    • Four fibrous rings around valves: left AV ring (mitral or bicuspid), right AV ring (tricuspid), aortic ring, pulmonary ring.

    • Functions: anchor valves; prevent over-dilation; insertion for bundles; block spread of electrical impulses.

      • Aortic and pulmonary rings have three cusps each and three c-shaped fibrous attachments for cusp bases; these extra attachments are not present with the AV rings.

      • Papillary muscles and chordae tendineae anchor AV valves to ventricle walls, preventing valve prolapse.

Chambers of the Heart

  • Four chambers: 4: two atria (left, right) and two ventricles (left, right).

    • Interatrial septum separates the atria; fossa ovalis is the fetal remnant of the foramen ovale.

    • Atria have auricles; right atrium anterior surface contains pectinate muscles; left atrium interior is smooth (pectinate muscles mainly in left auricle).

Ventricles and Internal Structures

  • Ventricles are the discharging chambers; interventricular septum separates them.

  • Internal wall has trabeculae carneae; papillary muscles anchor chordae tendineae to AV valves.

  • Right ventricle forms most of the anterior surface; left ventricle cavity is more circular and the wall is thicker.

  • Thicker myocardium = greater force/pressure; both ventricles pump equal blood volume per beat and contract simultaneously.

Valves and Blood Flow

  • Right AV valve = tricuspid; Left AV valve = mitral (bicuspid).

  • Semilunar valves: pulmonary valve and aortic valve.

  • Chordae tendineae + papillary muscles stabilize AV valves during ventricular contraction.

  • Ligamentum arteriosum is a remnant of the ductus arteriosus; connects the pulmonary trunk to the aorta.

External Grooves and Fat

  • Atrioventricular groove (coronary sulcus) surrounds the heart and houses major coronary vessels.

  • Interventricular grooves (anterior and posterior interventricular sulci) also contain vessels and adipose tissue.

  • Epicardial fat in these grooves cushions vessels.

Great Vessels and Blood Flow

  • Great vessels attached to the heart: aorta, pulmonary trunk, superior vena cava, inferior vena cava, pulmonary veins.

  • Veins drain toward the heart; arteries carry blood away from the heart.

  • Fetal remnants: foramen ovale → fossa ovalis; ductus arteriosus → ligamentum arteriosum.

Right vs Left Ventricle: Shape, Thickness, Function

  • Right ventricle cavity shape: crescent; Left ventricle cavity: circular.

  • Left ventricle wall thicker; generates higher pressure to pump systemically; right ventricle pumps to the lungs.

  • Despite differences, both ventricles eject equal blood volume and contract simultaneously; atrial contraction precedes ventricular contraction.