Heart

• cardiology


  the scientific study of the normal heart and the diseases associated with it
• Location of the Heart

  The heart rests on the diaphragm, near the midline of the thoracic cavity in the mediastinum

  - 2/3 of the mass of the heart lays on the LEFT of the midline
• mediastinum


  an anatomical region that extends from the sternum to the vertebral column, the first rib to the diaphragm, and between the coverings (pleurae) of the lungs
• apex of the heart

  pointed end of the heart; formed by the tip of the left ventricle (a lower chamber of the heart)

  - rests on the diaphragm

  - directed anteriorly, inferiorly, and to the left
• base of the heart

  posterior aspect of the heart; opposite the apex

  - formed mostly by theleft atrium(into which the four pulmonary veins open)

  - a portion of theright atrium(which receives the superior and inferior vena cavae and the coronary sinus)
• anterior surface


  deep to the sternum and ribs
• inferior surface


  portion of the heart that rests mostly on the diaphragm and is found between the apex and right surface
• right surface


  faces the right lung and extends from the inferior surface to the base
• left surface


  faces the left lung and extends from the base to the apex
• surface projection


  outlined shape of an organ on the surface of the body

  ---> Four point (landmarks) of the heart reveal size and shape of heart
• superior right point


  superior border of the third right costal cartilage about 3 cm to the right of midline
• superior left point


  inferior border of the second left costal cartilage about 3 cm to the left of midline
• inferior left point


  in the fifth left intercostal space, about 9 cm to the left of the midline; (located superficial to the apex of the heart)
• inferior right point


  the superior border of the sixth right costal cartilage, about 3 cm to the right of the midline
• pericardium


  membrane that surrounds and protects the heart

  consists of two parts:

  (1) fibrous pericardium

  (2) serous pericardium
• fibrous pericardium


  superficial layer, consists of touch dense irregular connective tissue

  Functions:

  - prevents overstretching of heart

  - protection

  - anchors heart to mediastinum
• serous pericardium


  deeper, thinner, more delicate membrane that forms a double layer around the heart
• parietal layer of serous pericardium

  outer layer of the serous membrane;

  fused to the fibrous pericardium
• visceral layer of serous pericardium


  inner layer of the serous membrane on the heart;

  also calledepicardium
• pericardial fluid


  serous fluid between parietal and visceral layers of pericardium

  - reduces friction when heart beats
• pericardial cavity


  space between the parietal and visceral layers of pericardium that contains pericardial fluid
• pericarditis


  inflammation of the pericardium
• cardiac tamponade


  acute compression of the heart caused by fluid accumulation in the pericardial cavity
• Cardiopulmonary resuscitation (CPR)


  refers to an emergency procedure for establishing a normal heartbeat and rate of breathing
• 3 Layers of the Heart

  (1) epicardiumm

  (2) myocardium

  (3) endocardium
• epicardium


  outermost layer of the heart

  - contains blood vessels, lymphatics, and nerves
• 2 layers of Epicardium

  (1) visceral layer of the serous pericardium

  - composed of mesothelium

  (2) fibroelastic and adipose tissue
• myocardium


  the cardiac muscle layer of the heart wall

  - responsible for pumping action of the heart

  - cardiac muscle tissue held together byintercalated discs
• intercalated discs


  junctions between cardiac muscles;

  containsdesmosomes(hold fibers together) andgap junctions(allow muscle action potentials)
• endocardium


  membrane lining the inside chambers of the heart
• Myocarditis


  is an inflammation of the myocardium that usually occurs as a complication of a viral infection, rheumatic fever, or exposure to radiation or certain chemicals or medications.
• Endocarditis


  refers to an inflammation of the endocardium and typically involves the heart valves.
• systemic pump


  left side of the heart

  - comprised of the left atrium and left ventricle

  --> circulates oxygenated blood to all systems of the body <---
• auricle


  wrinkled, pouch-like structure on the anterior surface of each atrium (left and right)

  - slightly increases their blood-holding capacity
• sulci


  series of grooves on the surface of the heart

  - contain coronary blood vessels and fat (adipose tissue)
• coronary sulcus


  encircles most of the heart and marks the external boundary between the superior atria and inferior ventricles
• anterior interventricular sulcus


  groove on the anterior surface of the heart that marks the external boundary between the right and left ventricles
• posterior interventricular sulcus


  groove that marks the external boundary between the ventricles on the posterior aspect of the heart
• 4 Chambers of the Heart

  right atrium, right ventricle, left atrium, left ventricle
• right atrium


  the upper right chamber of the heart

  - receivesde-oxygenated bloodfrom thevenae cavaeandcoronary sinus