The Heart

Characteristics of the Heart: 

• Cone shaped 

• 12 cm long, 9 cm wide, 6 cm thick 

• Male: 300 g, Female: 250 g 

• Back of our sternum, in front of vertebral column 

• 3 inches from the midline, tilts to the right 

• Base points to right shoulder, apex points to left hip 

• Pericardial: sac that surrounds the heart

  • outer layer: fibrous (parietal)

  • inner layer: double-layered (visceral/epicardium) 

  • Pericardial cavity 

• Muscle, three layers of the heard 

  • Outer: epicardium 

  • Middle: myocardium - major portion of the heart, 95% 

    • Myocardio infarction: blocking of the myocardium 

  • Inner: endocardium 

• Blood vessels: 

  • Artery: usually carries oxyblood away from the heart to a capillary 

  • Vein: usually carries deoxy blood  

  • Capillary: where you drop the blood off  

    • when you get cut and bleed it's a capillary 

• Four chambers: 

  • Atrial-Ventricular groove: over the heart like a crown  

  • Inter Atrial ventricular septum- divides atriums 

  • Interventricular septum- divides ventricles 

  • Right side deoxyblood, left side oxyblood 

  • Right atrium 

    • 2-3 mm thick  

    • First chamber to receive deoxy blood  

    • Anterior side has auricle: pouch, increases volume of blood  

      • Holds pectinate - makes it rough, granular  

  • Left Atrium 

    • Thicker 

    • oxyblood 

  • Right Ventricle 

    • 4-5 mm 

  • Left Ventricle 

    • 10-15 mm, largest chamber 

    • Both ventricles have scratches called trabecular carinae (TC) 

• Valves: 

  • Tricuspid valve: between right atrium and right ventricle  

  • Bicuspid valve (Mitral): between the left atrium and left ventricle  

  • Pulmonary Semi-Lunar: artery that leads to the lungs 

  • Aortic Valve: leads to largest artery in body = aorta 

• Veins: 

  • Superior Vena Cava: largest vein in body, brings deoxy blood from above diaphragm into right atrium 

  • Inferior Vena Cava: brings deoxy blood from below the diaphragm  

• Coronary Sinus: has a thespian valve, brings deoxyblood from the heart  

• Arteries: 

  • Pulmonary artery: carries deoxy blood to the lungs 

    • Four pulmonary veins bring, now oxyblood, back to left atrium  

  • Aorta: all oxy blood now goes to this artery and is given off to body, three branches 

    • Ascending aorta: gives off blood to right and left coronary arteries (nourishes heart) 

  • All arteries carry oxy except pulmonary 

  • All veins carry deoxy except pulmonary