circulatory system

• coronary arteries

  the two arteries that supply blood to the heart muscle
• tricuspid valve

  valve between the right atrium and the right ventricle
• bicuspid valve

  valve between the left atrium and the left ventricle.
• single circulation

  a circulatory system consisting of a single pump and circuit, in which blood passes from the sites of gas exchange to the rest of the body before returning to the heart
• Double circulatory system

  Blood passes through the heart twice in one complete circuit of the body e.g. in a human
• smooth muscle


  Involuntary muscle found inside many internal organs of the body
• pulmonary artery


  artery carrying deoxygenated blood from the heart to the lungs
• pulmonary veins


  Deliver oxygen rich blood from the lungs to the left atrium
• Semi-lunar valves


  Valves in either side of the heart that controls exit from the ventricles.
• septum


  Divides the right and left chambers of the heart
• sinoatrial (SA) node


  A specialized area of cardiac tissue, located in the right atrium of the heart, which initiates the electrical impulses that determine the heart rate; often termed the pacemaker for the heart.
• atrioventricular node


  A specialized mass of conducting cells located at the atrioventricular junction in the heart.
• Bundle of His


  a bundle of modified heart muscle that transmits the cardiac impulse from the atrioventricular node to the ventricles causing them to contract
• Purkyne fibres


  tissue that conducts the wave of excitation to the apex of the heart.
• lymph


  watery fluid derived from tissue fluid
• cardiac cycle


  A complete heartbeat consisting of contraction and relaxation of both atria and both ventricles
• Diastole


  Relaxation of the heart
• Systole


  Contraction of the heart
• Thrombin


  enzyme that converts fibrinogen to fibrin during coagulation
• thromboplastin


  essential factor in the production of thrombin and blood clotting
• Platelets


  blood clotting fragments of cells
• atheroma


  a deposit of plaque on or within the arterial wall
• Atherosclerosis


  Changes in the walls of large arteries consisting of lipid deposits on the artery walls.
• thrombus


  blood clot