Cardiovascular

• Cardiovascular system


  The transport system of the body that pumps and channels blood containing glucose and oxygen around the body
• Cardiovascular system


  • Consists of three parts: the blood, the heart, and the blood vessels
• Double circulatory system


  Consists of pulmonary circulation and systemic circulation
• As a student nurse, understanding the structure and function of the cardiovascular system is essential
• Knowledge of the cardiovascular system has clinical relevance and application
• Functions of the cardiovascular system


  Transport, protection, homeostasis and regulation
• Blood


  Viscous fluid, red body fluid that flows through all the vessels except the lymphatic vessels, constitutes about 8% of the total body weight
• Functions of blood


  • Transport oxygen, carbon dioxide, nutrients, waste products, hormones
  • Regulate normal body temperature, pH, protect against blood loss and foreign microbes
• Components of blood


  • Formed elements (45% of blood volume)
  • Plasma (55% of blood volume)
• Erythrocytes (red blood cells)

  • Produced in bone marrow, contain haemoglobin, life span of 120 days, broken down in the spleen
• Leucocytes (white blood cells)

  • Granular leucocytes: neutrophils, eosinophils, basophils
  • Agranular leucocytes: lymphocytes, monocytes
• Thrombocytes (platelets)


  • Produced from megakaryocytes, play a major role in haemostasis (blood clotting)
• Haemostasis


  Has three main components: vasoconstriction, platelet aggregation, coagulation
• Red blood cells contain haemoglobin which is an oxygen binding molecule and carries the waste product carbon dioxide away to the lungs
• Platelets are used in the blood clotting cascade and have surface receptors which attract white blood cells such as leukocytes
• White blood cells are used for the inflammation response process and are made up of monocytes, eosinophils, basophils, lymphocytes, and neutrophils
• Plasma


  Straw-coloured liquid when the formed elements are removed from the blood, consists of water, mineral salts, plasma proteins, foodstuffs, enzymes, hormones, antibodies and antitoxins
• Venepuncture


  Withdrawing of blood for laboratory testing, veins are used instead of arteries because they are closer to the surface and more readily accessible, and contain blood at a much lower pressure
• Plasmapheresis


  A procedure in which blood is withdrawn from the body, its components are selectively separated, the undesirable component causing disease is removed and the remainder is returned to the body
• Mechanisms to prevent blood loss

  1. Vascular spasm

  2. Platelet plug formation

  3. Blood coagulation
• Haemophilia


  An inherited condition that affects the blood's ability to clot, leading to spontaneous bleeding and bleeding following injuries or surgery
• ABO blood group system


  Based on two agglutinogens A and B, individuals can have blood type A, B, AB, or O
• Rhesus (Rh) factor


  Genetically determined antigens on the surface of erythrocytes
• Blood group A individuals manufacture only agglutinogen A, blood group B individuals manufacture only agglutinogen B, blood group AB individuals manufacture both agglutinogens A and B, and blood group O individuals manufacture neither
• Blood group O is the universal donor, and blood group AB is the universal recipient
• Agglutinated cells can block blood vessels and may lead to kidney or brain damage and death
• An example of an incompatible blood transfusion is transfusing blood group A to someone with blood group B