Blood - biology and public health BIO116.pptx

Blood – biology and public health BIO116 Dr Kaaren Mathias MBChB, MPH, PhD,FNZCPHM Overview of learning objectives Students will be able to Understand the key structures in blood Increase their knowledge of the role and function of blood with a focus on red blood cells...

Blood – biology and public health BIO116 Dr Kaaren Mathias MBChB, MPH, PhD,FNZCPHM Overview of learning objectives Students will be able to Understand the key structures in blood Increase their knowledge of the role and function of blood with a focus on red blood cells Describe how haemoglobin delivers and off-loads oxygen to peripheral tissues Describe the primary causes of anaemia Outline the key public health responses to anaemia What are key structures in blood? Red blood cells (erythrocytes) Shaped like donuts No nucleus Like a raft that carries oxygen from lungs to the ‘distal’ tissues and then bring the ‘waste’ CO2 back to lungs Last around four months There are a lot – e.g. every second 2 million new RBCs enter the blood stream When they get tatty they are filtered out by liver and spleen and recycles RBCs carrying oxygen and carbon dioxide Red blood cells Carry an antibody on the outside A, B or Rh factor This mostly matters if you need a transfusion White blood cells Have ameboid movement Most can ingest other cells or particles (phagocytosis) Are attracted by specific stimuli Can migrate out of the blood stream Platelets Look like broken bits of a plate Help with clotting Release chemicals to help clots occur Patch up holes on the inside of blood vessels Help blood vessels that are damaged to contract (get smaller) What are the key functions of blood? Transport nutrients, gases, wastes and hormones Regulation of body pH (keep it at 7.4) Restrict fluid loss linked to injury Defend the body against outsiders (pathogens) and poisons (toxins) Regulate the body temperature Transport Transport nutrients, gases, hormones and wastes Restriction of fluid loss The coagulation cascade and platelets plug a hole in a blood vessel Defend the body against outsiders There are WBCs that form antibodies e.g. lymphocytes Or that ingest outsiders (phagocytosis) eg neutrophils, macrophages, eosinophils, basophils or monocytes 4000 – 11,000 per microlitre What happens with blood system disorders? Blood clotting doesn’t work Too many RBCs = leading to blood loss or polycythaemia haemorrhage Too few RBCs = anaemia e.g. too few platelets after dengue infection or problems with clotting factors (haemophilia) Too few or poorly functioning WBCs e.g. HIV/ AIDs Uncontrolled growth of WBCs = leukaemia Anaemia Haemoglobin, in the Focus of Laboratory 2 normal adult, is a red- coloured protein in the blood whose main function is to transport oxygen from the lungs to tissues and to transport carbon dioxide from tissues to the lung. What are possible symptoms of someone with anaemia? Why does anaemia matter? Anaemia contributes to poor cognitive and motor development in children Anaemia reduces work capacity in adults Anaemia increases poor outcomes of pregnancy Iron deficiency anaemia and blood Anaemia is lack of red blood cells Haemoglobin is a red protein in red blood cells that helps them carry oxygen Red blood cells are made in the bone marrow (inside long bones) What changes do you expect to see in iron deficiency anaemia? Fewer RBCs Smaller RBCs Hypochromic RBCs Which full blood slide might show iron deficiency anaemia?  Iron deficiency anaemia 29.6% of women globally 39.8% of pre-schoolers globally Why are these places in the world experiencing more anaemia? Why are women more anaemic than men? Why more children than adults? https://www.who.int/data/gho/data/themes/topics/anaemia_in_women_and_children Causes of IDA Treatment of iron deficiency Dietary Iron supplement Iron injections What would you select to address widespread anaemia in a community? Why? Sickle cell anaemia Inherited disorder causing rigid RBCs and anaemia Prevalent – people with African ancestry – also in Middle –East and South Asia Leads to increased risk of stroke, infections, kidney failure, heart problems BUT heterozygote carriers have less severe malaria = selective advantage Why does anaemia matter? Anaemia contributes to poor cognitive and motor development in children Anaemia reduces work capacity in adults Anaemia increases poor outcomes of pregnancy Sickle cell anaemia Inherited disorder causing rigid RBCs and anaemia Prevalent – people with African ancestry – also in Middle –East and South Asia Leads to increased risk of stroke, infections, kidney failure, heart problems BUT heterozygote carriers have less severe malaria = selective advantage What changes do you expect to see in someone with sickle cell anaemia? Look at the morphology of the RBCs How might your differentiate the shape of an RBC end-on vs sickled? Summary – can you answer these questions? What are the functions of blood? Can you draw the structures of RBCs, WBCs and platelets? What do each of these elements of blood do? What are some of the causes of anaemia? How might someone with anaemia present to a health provider? How is iron deficiency anaemia diagnosed ? And treated? Patai? [email protected]