circulatory system

• Plasma


  Liquid part of blood, 55% of blood volume

  Mixture of water with dissolved substances such as salts and sugars
• Function of plasma


  To transport the components of blood, including cells, nutrients, wastes, hormones, proteins and antibodies, throughout the body
• Formed elements


  Non-liquid part of blood, consisting of erythrocytes, leucocytes, and thrombocytes
• Erythrocytes


  Red blood cells lacking a nucleus, responsible for oxygen transport (40-45%)
• Leucocytes


  White blood cells involved in immune response and infection protection (1%)
• The 5 different leucocytes

  Neutrophils, Monocytes, Lymphocytes (T-lymphocytes + B-lymphocytes), Basophils, Eosinophils
• Thrombocytes


  Platelets aiding in blood clotting by forming a scaffold (<1%)
• Oxyhaemoglobin


  Compound of oxygen and hemoglobin, transporting oxygen in blood

  Combination is loose because oxyhaemoglobin can easily break down to release the oxygen
• The % of oxygen carried in combination with haemoglobin molecules

  97%
• Haemoglobin


  Protein in red blood cells combining with oxygen for transport
• When and where does oxygen combine with haemoglobin

  When the oxygen concentration is relatively high

  Occurs in the capillaries in the lungs, where oxygen diffuses into the blood from the air in the alveoli
• When does oxyhaemoglobin break down

  Oxyhaemoglobin breaks down to haemoglobin and oxygen when the concentration of oxygen is relatively low
• Oxygenated blood


  Blood with a high proportion of oxyhaemoglobin
• Carbaminohaemoglobin


  Compound of carbon dioxide and hemoglobin in blood
• Transport of carbon dioxide

  Carbon dioxide can be transported by dissolving in plasma as carbaminohaemoglobin or as bicarbonate ions, carried in the plasma
• Nutrients


  the essential elements and molecules that are obtained from the food we eat
• Blood clotting


  helps to minimise blood loss from the broken vessels and prevent the entry of infecting micro-organisms
• Vasoconstriction


  Immediate constriction of injured arteries to reduce blood flow
• Platelet plug


  Formation at injury site to reduce blood loss and attract more platelets
• Coagulation


  Complex process forming a fibrin mesh to trap blood cells and form a clot
• Serum


  Fluid squeezed out during clot retraction after clot formation
• What happens when a clot dries

  a scab is formed over the wound to prevent entry of infecting micro-organisms
• Organic wastes


  Substances like urea and creatinine carried in blood plasma
• Organic nutrients


  Dissolved in the blood plasma include glucose, vitamins, amino acids, fatty acids and glycerol (Contains carbon)
• Inorganic nutrients


  Ions like sodium, calcium, potassium, chloride, and iodide in blood plasma
• Metabolic waste


  substances produced by the cells that cannot be used and would be harmful if allowed to accumulate
• The heart


  The pump that pushes the blood around the body, located between the two lungs in the mediastinum, behind and slightly to the left of the sternum
• Pericardium


  A membrane that encloses the heart and holds it in place but also allows the heart to move as it beats
• Cardiac muscle


  makes up the thick middle layer of the heart
• Septum


  a wall that separates the left and right side of the heart
• The right side of the heart

  collects blood from the body and pumps it to the lungs
• The left side of the heart

  receives blood from the lungs and pumps it to the rest of the body
• Right atrium


  receives blood from the body and passes it to the right ventricle
• Right ventricle


  pumps blood to the lungs
• Left atrium


  receives blood from the lungs and passes it to the left ventricle
• Left ventricle


  pumps blood to the body
• What wall is thicker, left or right ventricle?

  The wall of the left ventricle is thicker because it needs to be much stronger to pump the blood through the blood vessels supplying the body
• Valve


  Ensure that the blood can only flow in one direction
• Atrioventricular valves


  Located between the atria and the ventricles

  Flaps of thin tissue with the edges held by tendons, called chordae tendineae, that attach to the heart on papillary muscles

  Blood must then leave the heart through the arteries and not flow back into the atria
• Semilunar valves:


  Stops blood from flowing back into the ventricles when the ventricles relax.

  Each semilunar valve has three cusps

  When blood tries to flow back into the ventricle, the cusps fill out and seal off the artery, ensuring that the blood only flows in one direction