Roles of Blood
Delivery of nutrients and oxygen
Composition Cellular Components
• Water • Electrolytes • Proteins
• Erythrocytes (RBC) • Leucocytes (WBC) • Platelets 55% 45%
+ dissolved nutrients and waste materials
Structure Biconcave disc Packed with haemoglobin No nucleus
Function Transport of oxygen (and carbon dioxide)
Removal of waste products
Straw coloured liquid
1.Transport nutrients • Glucose • Amino acids • Fatty acids • etc. 2.Transport waste products • CO2 • Urea • Lactic acid 3.Homeostasis • Temperature • Acid-base balance • etc.
Contents Water Electrolytes o Na+ (Sodium ions) o K+ (Potassium ions) o Ca2+ (Calcium ions) o Mg2+ (Magnesium ions) o Cl- (Chloride ions) o HCO3- (Bicarbonate ions) o PO43- (Phosphate ions) Proteins o Albumin o Immunoglobulins o Others
Leucocytes Lymphocyte Structure: Small, little cytoplasm, no RER (i.e. inactive) Function: Adaptive immunity to viruses
Neutrophil Structure: Multi-lobular nucleus, granules Function: 1st line defense against bacteria (Phagocytosis)
Natural Killer cell Structure: Large, lymphocyte-like, but with distinct granules Function: Destroys virus infected cells
Eosinophil Structure: Normally transparent, stain brick red, granules. Function: Defense against parasites
Monocyte Structure: Large kidney-shaped nucleus, granules Function: Develop into macrophages on entering tissues, then act by phagocytosis
Basophil Structure: Many large granules which when stained obscure a bi-lobular nucleus Function: Probably similar to mast cells
Where is blood made? Bone marrow
…fragments of huge megakaryocytes
Femur Pelvis Sternum
Function: Secrete growth factors which promote repair and regeneration of connective tissue. Blood clotting
Anaemia Definition Level of haemoglobin in blood lower than normal
Iron Deficiency Anaemia Sources
Microcytic Low Hb Low MCV
Normocytic Low Hb Normal MCV
Macrocytic Low Hb High MCV
MCV = Mean Corpuscular Volume – just a way of saying how big it is Possible Causes Iron-deficiency Thalassaemia
Possible Causes Acute blood loss Malignancy Infection Inflammation
Possible Causes Vit B12 deficiency Folate deficiency Alcohol abuse Hypothyroidism Bone marrow dysfunction
Meat, liver, green vegetables, flour, eggs… lots!
Causes Chronic blood loss • Gastrointestinal bleeding • Heavy periods Dietary inadequacy • Uncommon, can be at lower limit then exacerbated by increased demand Failure of iron absorption • Drug interaction • Malabsorption diseases, e.g. Coeliac disease Excessive requirements • Growth spurts • Pregnancy
• Commoner in the Mediterranean • Inherited abnormality of haemoglobin production • Imbalance of various Hb chains = instability and haemolysis • Some forms not compatible with life...
A very complex pathway
DNA synthesis necessary for the production of red blood cells
Sources Not synthesised by plants or animals. It must be sourced directly or indirectly from bacteria. Dietary (indirect) sources: fish, meat, poultry, eggs, milk
Sources Green leafy vegetables Fortified cereals
Absorption Bonds with a protein called ‘Intrinsic Factor’ in the stomach and is absorbed in the terminal end of the small intestine.
Absorption Upper small intestine. Only a small amount stored in the body. Metabolism is interfered with by a number of drugs.
Sickle Cell Anaemia • Autosomal recessive mutation • Forming sickle cell haemoglobin (HbS) • Easily destoryed = haemolytic anaemia • Common in West Africans and Afro Caribbeans as being a carrier, protects against malaria