Blood, Heart and blood vessels

• liquid part of blood made up of about 90% water, 7% protein and 3% dissolved substances
• plasma is a pale yellow colour
• plasmas function is to transport
• dissolved materials in plasma include glucose, amino acids, minerals, vitamins and hormones
• plasma transports water including urea, salts and CO2
• plasma also transports heat (involved in homeostasis)
• RBCs have a biconcave shape (for extra surface area for transporting oxygen)
• RBCs are made in the bone marrow of long bones
• RBCs have a nucleus when first made but when they become mature their nucleus dies
• RBCs contain no mitochondria and so do not respire
• RBCs only live for about 4 months as they cannot respire themselves - broken down in the liver and spleen
• RBCs - the liver and spleen breaks down the haemoglobin into the pigments Bilirubin and biliverdin which get sent to the gall bladder and are secreted into bile
• RBCs determine blood group
• function of RBCs is to transport oxygen
• the globular protein pigment haemoglobin is responsible for carrying the oxygen
• White blood cells are large flattened discs
• WBCs do not contain a nucleus and mitochondria
• WBCs are about twice the size of RBCs
• WBCs are made in the bone marrow and some mature in the lymph system
• function of WBCs is to fight infection
• 2 main types of WBC - lymphocytes and monocytes
• lymphocytes are made in the bone marrow and are stored in the spleen and the lymphatic system - they have large rounded nucleus that almost fills the entire cell - make antibodies to fight off disease
• monocytes engulf foreign bodies which is known as phagocytosis - do not live as long as lymphocytes (only a few days) and usually have a kidney shaped nucleus
• functions of blood - to transport food (salts, CO2, hormones and heat in plasma and oxygen in RBCs), fight infection (WBCs and platelets)
• platelets are made in the bone marrow and are fragments of cells
• platelets have no nuclei
• blood clots prevent blood loss and prevent the entry of foreign cells into the body
• blood group A - can receive blood from A or O and can donate to A
• blood group B - can receive blood from B or O and donate to B
• blood group AB - can receive blood from A or B or AB or O and donate blood to AB
• Blood group O - can receive blood from O and donate to A or B or AB or O
• Because Group AB can receive blood from every type it is known as the universal recipient
• Because group O blood can be donated safely to every blood group it is known as the universal donor
• a person who is Rhplus can donate blood to a Rhplus person and can themselves receive blood from a Rhplus or Rhminus person
• a person who is Rh-minus can receive blood from a Rh-minus but if given Rh-plus blood a serious reaction can occur
• a Rh-minus person can donate blood to a Rh-plus and Rh-minus
• in an open circulatory system, blood is pumped by the heart into different blood vessels. The blood then leaves these vessels and passes slowly through different parts of the body and it then rejoins blood vessels and is carried back to the heart
• advantages of a closed system - blood can flow faster, the flow of blood to different parts off the body is easier to regulate (more blood can be directed to out muscles if needed)
• arteries have thick though elastic walls and a small lumen
• arteries do not contain valves and blood is under high pressure and flows in pulses