Cardiovascular System

• Shaped like a blunt cone and is approximately

  the size of a closed fist. Positioned obliquely between the lungs in the

  mediastinum?

  Adult Heart
• • blunt, rounded point of the heart.
  • directed anteriorly and slightly inferiorly
  • located deep to the 5th intercostal space to the left of the sternum and medial to the midclavicular line?

  Apex
• • larger, flat part at the opposite end of the heart
  • directed posteriorly and slightly superiorly
  • located deep to the sternum and extends to the 2nd intercostal space?

  Base
• • also pericardial sac
  • is a double layered, closed sac that surrounds the heart?

  Pericardium
• • tough, fibrous connective tissue outer layer
  • prevents overdistension of the heart and anchors it within the mediastinum?

  Fibrous pericardium
• thin, transparent, inner layer of simple squamous epithelium?

  Serous Pericardium
• 2 types of Serous Pericardium?

  Parietal and Visceral
• part of the serous pericardium lining the fibrous pericardium?

  Parietal pericardium
• part covering the heart surface?

  Visceral pericardium
• Layers of the Heart?

  Pericardium cavity, Epicardium, Myocardium, Endocardium
• separates epicardium and serous pericardium?

  Pericardial cavity
• (visceral pericardium) – outermost layer?

  Epicardium
• middle muscular layer, responsible for heart’s contraction?

  Myocardium
• lines the heart and its valves?

  Endocardium
• receives blood from upper body?

  Superior vena cava (SVC)
• receives blood from lower body?

  Inferior vena cava (IVC)
• drains blood from heart?

  Coronary sinus
• • right and left artery
  • carries deoxygenated blood to lungs?

  Pulmonary trunk
• return oxygenated blood to heart?

  Pulmonary veins (four)
• • carries oxygenated blood out to body
  • Branches: Brachiocephalic, (L) common carotid, (L) subclavian
  • Aortic arch, descending thoracic, abdominal?

  Ascending aorta
• Right Atrium – has 3 major openings

  o SVC and IVC – receive blood from the body

  o Coronary sinus – receives blood from the heart itself
• receive blood from the four pulmonary veins?

  Left Atrium
• opens into the pulmonary trunk. Pumps blood into the lungs?

  Right Ventricle
• opens into the aorta. Pumps blood through the systemic circulation?

  Left Ventricle
• • Allow blood to flow from the atria into the ventricles but prevent blood from flowing back into the atria
  • Larger and have a softer closure?

  Atrioventricular Valves (AV valves)
• valve between right atrium and right ventricle?

  Tricuspid valve
• valve between left atrium and left ventricle?

  Bicuspid (Mitral) valve
• attach to ventricles by chordae tendineae?

  cusps
• • keeps blood from flowing back into the ventricles
  • Rapid snap closure, smaller openings, subjected to greater mechanical abrasion (rapid ejection of blood)?

  Semilunar Valves (SV valves)
• 2 types of Semilunar Valves (SV valves)?

  Pulmonary and Aortic
• • Right ventricle
  • Pulmonary trunk exits the heart?

  Pulmonary valve
• • Left ventricle
  • Ascending aorta leaves the heart?

  Aortic valve
• • carries deoxygenated blood to the lungs and returnsit to the left atrium of the heart
  • In the lungs, carbon dioxide diffuses from the blood into the lungs, and oxygen diffuses from the lungs into the blood?

  Pulmonary Circulation
• • Delivers oxygenated blood and its nutrients to all the remaining tissues of the body.
  • From those tissues, carbon dioxide and other waste products are carried back to the right side of the heart?

  Systemic Circulation
• • Cardiac muscle cells are elongated, branching cells that

  have one, or occasionally two, centrally located nuclei.

  • Cardiac muscle has a smooth sarcoplasmic reticulum, but

  it is not as regularly arranged as in skeletal muscle fibers
• • The T tubules in cardiac muscle are larger in diameter

  than in skeletal muscle

  • Slow onset of contraction and the prolonged contraction

  phase in cardiac muscle

  • Rich in mitochondria and extensive capillary network
• • The cells are bound end-to-end and laterally to adjacent

  cells by specialized cell-to-cell contacts called intercalated

  disks

  • Gap junctions allow cytoplasm to flow freely between

  cells, resulting in areas of low electrical resistance

  between the cells

  • Electrically, the cardiac muscle cells behave as a single

  unit
• relays action potentials through the heart. Pacemaker controls the rate of the beat of heart?

  A conducting system
• • Pacemaker of the Heart; initiates impulse (self-excitation).

  • Located superior posterolateral wall, just medial to the opening of the superior vena cava?

  Sinoatrial (SA) node
• • sends impulse to AV bundle

  • Delay of impulse from atria to ventricles

  • Located at the posterior wall of RA behind the tricuspid valve

  • Slow conduction mainly diminished number of gap junctions?

  Atrioventricular (AV) node