cardiovascular

• Main Functions of the Cardiovascular System

  • Oxygen and nutrients distribution
  • Carry cell wastes and CO2
  • Transport water, electrolytes, hormones and enzymes
  • Protect against disease
  • Prevent hemorrhage
  • Regulate blood temperature
• Components of the Cardiovascular System

  • Heart
  • Blood
  • Blood vessels (Veins, Arteries)

  
• Heart


  • Length: 12 cm (5")
  • Width: 9 cm (3.5") at broadest
  • Thick: 6 cm (2.5")
  • Mass: 250 g (female); 300 g (male)
  • About two-thirds of the mass of the heart lies to the left of the body's midline

  
• External Parts of the Heart

  • Apex
  • Base
• Distinct Surfaces of the Heart

  • Anterior
  • Inferior
  • Right
  • Left

  
• Heart Location


  • Lies in the mediastinum
  • Apex rests on diaphragm
  • Anterior surface: sternum-ribs
  • Inferior surface: diaphragm
  • Right surfaces: R lung-base
  • Left surfaces: L lung-base

  
• Parts of the Pericardium

  • Fibrous pericardium
  • Serous pericardium (Parietal layer, Visceral layer, Pericardial cavity)
• Fibrous Pericardium


  • Composed of tough, inelastic, dense irregular connective tissue
  • Prevents overstretching of the heart
  • Provides protection
  • Anchors heart in the mediastinum

  
• Serous Pericardium


  • Double layer of thinner and more delicate membrane
  • Parietal layer- outer
  • Pericardial cavity
  • Visceral layer- inner
  • Pericardial fluid reduces friction between layers
• Layers of the Heart

  • Epicardium (External)
  • Myocardium (Middle)
  • Endocardium (Inner)

  
• Epicardium


  • Smooth, slippery texture
  • Contains blood vessels, lymphatics, and vessels that supply the myocardium
  • Visceral layer: composed thin, transparent mesothelium
  • Fibroelastic tissue and adipose tissue: houses major coronary and cardiac vessels
• Myocardium


  • Responsible for pumping action of the heart
  • Cardiac muscle fibers are organized in bundles that swirl diagonally around the heart and generate the strong pumping actions
• Endocardium


  • Thin layer of connective tissue
  • Provides a smooth lining for the chambers of the heart and covers the valves
  • Continuous with the endothelial lining of the large blood vessels attached to the heart

  
• Chambers of the Heart

  • Atria (superior receiving)
  • Ventricles (inferior pumping)
• Right Atrium


  • Right border of heart
  • Receives blood from three veins: Superior vena cava, Inferior vena cava, Coronary sinus
  • Smooth posterior wall
  • Rough anterior wall: pectinate muscles
  • Interatrial septum: partition between atria
  • Prominent feature: Fossa ovalis

  
• Tricuspid Valve


  • Consists of three leaflets or cusps
  • AKA: Right Atrioventricular valve
  • Controls the flow of blood from right atrium to right ventricle
  • Prevents backflow of blood

  
• Right Ventricle


  • Anterior surface of the heart
  • Trabeculae carneae: bundles of cardiac muscle
  • Tricuspid valve are connected to tendon like cords: chordae tendineae: connected to papillary muscle
  • Interventricular septum: separates ventricles

  
• Pulmonary Valve


  • Consists of three leaflets or cusps
  • AKA: Pulmonary semilunar valve
  • Controls the flow of blood from right ventricle into large artery (pulmonary trunk)
  • Sends blood to the lungs

  
• Left Atrium


  • Forms most of the base of the heart
  • Receives blood from four pulmonary veins
  • Smooth posterior and anterior wall
  • Bicuspid (mitral) valve: AKA Left atrioventricular valve, controls flow from left atrium to left ventricle

  
• Left Ventricle


  • Thickest chamber of the heart
  • Forms apex of the heart
  • Has trabeculae tendineae and chordae tendineae- papillary muscle
  • Aortic valve: controls flow from left ventricle to ascending aorta
• Ductus arteriosus
• Differences between Atria and Ventricles

  • Atria: Deliver blood under less pressure into the adjacent ventricles, Thin walled
  • Ventricles: Pump blood under high pressure over greater distances, Thick walled
• Differences between Right and Left Ventricles

  • Right: Has a smaller workload, Pumps blood at a short distance to the lungs at lower pressure, Resistance to blood flow is small, Muscular wall is thinner, Perimeter of the lumen is somewhat crescent shaped
  • Left: Has a more workload, Pumps blood at a greater distances to all other parts of the body at higher pressure, Resistance to blood flow is larger, Muscular wall is thicker, Perimeter of the lumen is roughly circular

  
• Fibrous Skeleton
• Systole vs Diastole