ANAPHY Cardiovascular System

• Location of the heart

  • Thoracic Cavity

  • between lungs and inferior mediastinum
• Pericardium


  • Double Walled sac
• Fibrous Pericardium


  • Loose and superficial
• Serous Membrane


  • Deep in fibrous pericardium; has 2 layers
• Parietal Pericardium


  Outside layer; lines inner surface of the fibrous pericardium
• Visceral Pericardium


  • Next to the heart

  • also known as Epicardium
• Epicardium 


  • outer layer of the heart; visceral pericardium
• Myocardium


  • Middle Layer

  • consists of cardiac muscle
• Endocardium


  • Inner Layer

  • also known as Endothelium
• Atria


  • Receiving Chambers

  • Filling ventricles

  • Blood enters under low pressure
• Interatrial Septum


  • separates two atria longitudinally
• Ventricles


  • Discharging chambers

  • Thick walled pumps of the heart

  • During contraction, blood is propelled into circulation
• Interventricular Septum


  • separates two ventricles longitudinally
• Heart functions as double pump


  • Arteries carry blood away from the heart

  • Veins carry blood towards the heart
• Arteries


  • Pumps blood away from the heart
• Veins


  • Pumps blood towards the heart
• Pulmonary Circulation


  • Blood flows from the right side of the heart to the lungs and back to the left side of the heart

  • Oxygen-poor Blood: pumped to the right side of the heart through the pulmonary trunk, which splits into the pulmonary arteries, and takes oxygen-poor blood into the lungs

  • Oxygen-rich Blood: returns to the heart via pulmonary veins
• Systematic circulation


  • Oxygen-rich Blood: returned to the left side of the heart and is pumped out into the aorta

  • Oxygen-poor Blood: returns to right atrium via systematic veins, which empty blood into the superior or inferior vena cava
• Blood circulates to systematic arteries and to all body tissues
• Left ventricle is thicker because it pumps blood into the body through the systematic circuit
• Atrioventricular Valves


  • located between atria and ventricles

  • Valves anchor cusps in place by chordae tendineae to the walls of the ventricles

  • Open during heart relaxation as blood fills the chambers

  • Closes during ventricular contraction
• Semilunar Valves


  • located between ventricles and artery

  • Close during heart relaxation

  • Open during ventricular contraction
• Blood in the heart chambers does not nourish in the myocardium. The heart has its own nourishing circulatory system: coronary arteries, cardiac veins, coronary sinus
• Left Atrioventricular Valve: Bicuspid (mitral) valve

  Right Atrioventricular Valve: Tricuspid valve
• Coronary Arteries


  branch from the aorta to supply the heart muscle with oxygenated blood
• Cardiac Veins


  drains the myocardium of blood
• Coronary Sinus


  • large vein on the posterior of the heart

  • receives blood from cardiac veins
• Blood empties into the right atrium via the coronary sinus
• The cardiac muscle contracts spontaneously and independently of nerve impulse in a regular and continuous way.
• The atrial cells beat 60 times per minute
• Ventricular cells beat 20 to 40 times per minute
• Two systems regulate the heart activity: the Autonomic Nervous System and the Intrinsic Conduction System
• Intrinsic Conduction System


  • also known as Nodal System

  • composed of special nervous tissue that enforces a heart rate of 75 beats per minute

  • sets the heart rhythm

  • ensures that the depolarization of the heart muscle occur in one direction only, from the atria to the ventricles
• Sinoatrial (SA) Node


  • located in the right atrium

  • serves as the heart's pacemaker
• Atrioventricular (AV) Node


  Located at the junction of the atria and ventricle
• Atrioventricular (AV) bundle and bundle branches


  Located in the interventricular septum
• Purkinje Fibers


  Spread within the ventricle wall muscles
• Cardiac Cycle


  • refers to one complete heartbeat in which both atria and ventricles contract (systole) and then relax (diastole)

  • length is normally 0.8 second.
• Atrial Diastole


  • also known as Ventricular Filling

  • The heart is relaxed and the pressure within it is low

  • Atrioventricular valves are open allowing blood to passively flow into the atria and into ventricles

  • Semilunar valves are closed during this time
• Atrial Systole


  The ventricles remain relaxed while the atria contract, forcing blood into the ventricles to complete the ventricular filling