Introduction to Blood PDF

Title Introduction to Blood Presenter Associate Professor Mike Todorovic This session will focus on 4x learning outcomes, including; 1. Describ...

Title Introduction to Blood Presenter Associate Professor Mike Todorovic This session will focus on 4x learning outcomes, including; 1. Describe the composition & function of the layers of blood as obtained by haematocrit 2. Describe the process of haemostasis & the clotting cascade Why you should attend this session 3. Outline erythrocyte production (haematopoiesis) (covered in the prac/workshop) 4. Understand the basis of blood groups and apply to safe transfusion (covered in the prac/workshop) This session will lead into the blood workshop later in the week where learning outcome 4 will be covered. The following videos have been recorded to help support your learning. LO1: Composition and Function of Blood LO2: Haemostasis and Blood Clotting What you will need to do in preparation LO3: Haematopoiesis LO4: Blood Groups More information is also available on blood in Chapter 17 of Human Anatomy and Physiology, by Marieb. What you will need to bring Laptop, notebook and/or copy of the forum notes. Marieb & Hoehn., Human Anatomy and Physiology, Global Edition.  Composition of blood plasma Solutes continued… Marieb & Hoehn., Human Anatomy and Physiology, Global Edition. Marieb & Hoehn., Human Anatomy and Physiology, Global Edition. Figure 17.12 - Marieb & Hoehn., Human Anatomy and Physiology, Global Edition. Figure 17.13 Marieb & Hoehn., Human Anatomy and Physiology, Global Edition.  Reticulocyte: Mature in bloodstream in 1-2 days; indicator of level of Figure 17.11 erythropoiesis Marieb & Hoehn., Human Anatomy and Physiology, Global Edition. Figure 17.6 Marieb & Hoehn., Human Anatomy and Physiology, Global Edition. Figure 17.4 Marieb & Hoehn. Figure 17.7 Marieb & Hoehn. Blood Group Antigens  ABO Blood Group ABO gene encodes an enzyme with glycosyltransferase activity Enzyme modifies a cell surface glycoprotein – A allele adds N-acetyl galactosamine = A antigen – B allele adds galactose = B antigen – O allele does not modify the glycoprotein Saladin, Fig. 18-12 Paternity designation Agglutination & Haemolysis ABO Blood Group System Marieb New international edition p706  Rhesus (Rh) Factor Rhesus Monkey Another important antigen on the surface of RBCs – Blood containing this antigen is Rh+ – Blood lacking this antigen is Rh- Anti-Rh antibodies (known as anti-D) are only produced after exposure to the antigen – e.g. Rh- person is given blood from an Rh+ donor  Frequency of Blood Types in Australia O+ 40% O- 9% A+ 31% A- 7% B+ 8% B- 2% AB+ 2% AB- 1% https://bloodbrothers4lives.wordpress.com/tag/blood-types/ Over 80% are Rh+ Blood Group Compatibility http://www.donateblood.com.au/about-blood/types  Haemolytic Haemolytic disease of the newborn disease of the newborn  Haemolytic disease of the newborn Reported in over 20,000 babies a year in the USA alone In the past ~50 years anti-Rhesus antibodies have become standard Further information: More on of Rh-disease: https://www.ncbi.nlm.nih.gov/books/NBK2266/ http://emedicine.medscape.com/article/273995-overview Mothers who are Rh- receive the Anti-D during pregnancy, and within 72 hours of giving birth Neutralises the Rh+ antigen Normally at ~28 and ~34 weeks gestation (as an antenatal prophylaxis). The injection is normally given slowly by deep intramuscular injection, although in some cases intravenous administration of Anti-D immunoglobulin is warranted. Additional doses can also be given earlier in the pregnancy (ie: patient has a history of premature births) If a “sensitising event” occurs (examples next slide), then anti-D is also recommended to be given at that time Human Anatomy & Physiology, Marieb & Hoehn.  Sensitising Events Besides childbirth, other events in a woman’s history can sensitise her body to generate anti-D antibodies: Ectopic Pregnancy (fertilised egg implanted outside of the womb, commonly in a fallopian tube) Termination of Pregnancy Miscarriage (loss of baby prior to 20 weeks) Ultrasound-guided procedures such as: Fetoscopy (procedure to allow access to the fetus) Amniocentesis (amniotic fluid test) Chorionic villus sampling (placenta test for genetic analysis, ie: Down’s Syndrome) Cordocentesis (Umbilical cord blood sampling) Abdominal trauma that causes uterine activity and or abdominal pain For an Rh- female, the anti-D immunoglobulin should be given prior to Antepartum haemorrhage (genital bleeding during the late stages of pregnancy) these procedures, or as soon as possible External cephalic version (turning the fetus from breech positions into a head-down position for labour) For an Rh- female, the anti-D immunoglobulin should be given prior to these procedures, or as soon as possible  Haemolytic disease of the newborn Women who are Rh+ do NOT receive the Rh(D) Immunoglobulin What if sensitisation has occurred? (ie: a Rh- woman has developed anti-D antibodies) Special care and attention is provided to the mother and foetus, under the supervision of an obstetrician. Assessments are made early-on regarding the concentration of the antibodies. The foetus is managed to the best of the local health care’s requirements (ie, Foetal transfusions may be required if the foetus risks becoming anaemic, etc) In many areas of the world, appropriate healthcare is not available for this kind of occurrence. All of Australia’s anti-D plasma comes from a tiny pool of around 200 donors. Haemolytic disease of the newborn Child with Rh hemolytic disease of the newborn: The child has hydrops fetalis. Patients with Rh hemolytic disease have severe anemias, which lead to high output failure and both left and right heart failure, the latter responsible for peripheral edema and ascites. The liver in this fetus had massive hepatomegaly secondary to extramedullary hematopoiesis. USMLE Pathology Slides