PBL Reading Summary

Plasma • • • • • Blood is 8% of body weight: - 5.5 L in men and 5 L in women Blood consists of: - Erythrocytes - Leukocytes - Thrombocytes Platelets are cell fragments not cells Haematocrit refers to packed cell volume Centrifuge is a technique used to separate the blood into layers Plasma Proteins They are made in the liver, except antibodies which are made by lymphocytes Functions: • • • Make up the colloid pressure – starling forces - Helps with preventing excessive loss of plasma from the capillaries into the interstitial space Partial role in maintain capacity to buffer changes in pH Three types of plasma proteins: - Albumins: oncotic pressure - Globulins: - ✓ Alpha and beta: transport proteins. For things that cannot be transported around the body by themselves. For example, transferrin, which is used to transport iron. ✓ Gamma: makes antibodies Fibrinogen: is a key factor in blood clotting Erythrocytes • • • About 5 million per 1 ml They have disc shape, which is suited to their function of carrying oxygen and being able to squeeze through capillaries Structure: - Flat - Disc shaped on both sides - Biconcave shape -> provides larger surface area -> allows for gas exchange - Very thin: allows oxygen to diffuse really quickly - Flexible membrane -> allows them squeeze through capillaries - Contain Hb -> allows them to transport oxygen around the body - Lack of nucleus-> maximises SA - Have glycolytic enzymes, which are needed to fuel mechanisms involved in maintaining proper ionic concentrations within the cell - Lack mitochondria - Carbonic anhydrase -> needed for CO2 transport and catalyses a key reaction that leads to conversion of metabolically produced CO2 into bicarbonate, which is the primary form in which CO2 is transported in blood. - No DNA, RNA and ribosomes -> cannot undergo cell repair, growth or cell division - 120 days life span Role of Hb • • • • Only found in RBC Has to constituents: - Globin: protein made up of four highly folded polypeptide chains (2 alpha subunits and 2 beta subunits) - 4 heme groups which contain iron Hb is coloured because of its iron content Can also combine with: - CO2 - H+ of carbonic acid -> buffering system - CO - NO -> relaxation (dilation) of blood vessels Production of RBC • • • Since it cannot repair itself, with age it become fragile and prone to rupture as the cell squeezes through the capillaries Broken down in spleen Made in the red bone marrow • • • • Erythropoiesis is controlled by erythropoietin which is produced by the kidneys The primary trigger for the RBC production is hypoxia Low O2 stimulates the kidney to make erythropoetin, which is then secreted into the blood stream, then into the blood stream, then into the kidneys. I did not summaries the RBCs production for the RBC because it is long, and already made a mechanism for it from ninja nerd videos. Types of Anaemia Types Nutritional (iron deficiency) Pernicious Description Due to low iron intake. Iron is required for erythropoiesis in order to make Hb. Due to inability to indigest B12 from the digestive tract. Vit. B 12 from the normal RBC production and maturation. It is abundant in various foods and thus is rarely deficient in the diet. The issue occurs when the parietal cells of the stomach are unable to produce intrinsic factor. Aplastic Renal Haemorrhage Haemolytic Stickle cell Red bone marrow unable to make RBC, even though all the other requirements are available. This could be due to toxic chemicals, which destroy the red bone marrow, heavy exposure to ionizing radiation, invasion of the marrow due to cancer From kidney disease, when the kidney is unable to make erythropoetin Due to blood loss Rapture of too many circulating RBCs due to external factors such as malaria or stickle cell disease Genetic mutation that changes a single amino acid that makes up the beta chain of Hb. This results in a long jam blocks blood flow through the small vessels, leading to pain and tissue damage at the affected site. This makes it defective, fragile and prone o rupture ABO Blood types Leukocytes • • • Role in immune defence system Eliminate harmful foreign materials Main functions: - Defends against invading disease-producing microorganism - Remove worn out cells - Identifies and destroy cancer cells Types Type Neutrophils Eosinophils Basophils Monocytes Function • Engulf and destroy bacteria • Release bacteria chemicals into the ECF by exocytosis of granule contents to the cell exterior (degranulation) Increase in them is associated with allergic conditions (e.g., asthma and hay fever) and internal parasite infestations Make histamine, other anti-inflammatory mediators and heparin (anti-coagulant) • emerge from the bone marrow while still immature and circulate for only a B lymphocytes T lymphocytes day or two before settling down in various tissues throughout the body. • At their new location monocytes continue to mature and greatly enlarge, becoming large tissue phagocytes known as macrophages Make antibodies Directly destroy their target cells by releasing chemicals that punch holes in the victim cell • • Anaemia is defined as low RBC count It is reported as having low Hb or low haematocrit Symptoms • • • • • • • • Dizziness Increased heart rate Headache Pain Growth issues in children and teens Shortness of breath Cold hands and feet Tiredness and weakness Types • • • • • • • • Blood loss anaemia Iron deficiency Stickle cell Vit B12 deficiency Aplastic Lead poisoning: Lead is toxic to your bone marrow, causing you to have fewer red blood cells. Lead poisoning can happen when adults come into contact with lead at work, for example, or if children eat chips of lead paint. You can also get it if your food comes into contact with some types of pottery that aren’t glazed right. Thalassemia: issues with Hb formation Anaemia by RBC destruction: - Immune system attack - Enlarged spleen - Toxins for advanced liver or kidney disease Diagnosis Complete blood count Treatment Depends on cause • • • • If you have aplastic anaemia, you might need medication, blood transfusions (in which you get blood from another person), or a bone marrow transplant (in which you get a donor’s stem cells). If you have haemolytic anaemia, you might need medication that will hold back your immune system. Your primary care doctor may refer you to a doctor who specializes in vascular problems. If it’s caused by blood loss, you might have surgery to find and fix the bleeding. If you have iron-deficiency anaemia, you’ll probably need to take iron supplements and change your diet. Sickle cell anaemia treatment includes painkillers, folic acid supplements, intermittent antibiotics or oxygen therapy. A drug. called hydroxyurea (Droxia, Hydrea, Siklos) is often • • prescribed to decrease sickle cell pain crises (complicated mechanism). The medication called voxelator (Oxbryta) whichcan help your red blood cells keep their proper shape. Crizanlizumab-tmca (Adakveo) can keep the blood cells from sticking together and blocking vessels. L-glutamine oral powder (Endari) can cut down on your trips to the hospital for pain and also guard against a condition called acute chest syndrome. If you have a vitamin B12 or folate deficiency, you will be prescribed supplements.. Thalassemia doesn’t usually need treatment, but if your case is severe, you might have blood transfusions, a bone marrow transplant, or surgery. Absorption is regulated by: • • Dietary regulator: short term increase in dietary iron results in non-avid absorption as the mucosal cells have enough iron in them and thus block additional uptake Stores regulator: when iron stores have increased in the liver, hepcidin is released and prevents mucosal iron ferroprotein release and the enterocytes retain absorbed iron Iron storage takes two forms: • • Ferritin Hemosiderin Lab tests for iron include: • • • • • • Serum iron Serum iron binding capacity Serum ferritin Complete blood count Bone marrow biopsy Liver biopsy Iron deficiency limits: • • • • • • Oxygen delivery to cells Affects strength Reduces immunity Shortness of breath Sensitivity to cold Heart palpitations Groups at risk of low Iron • • • • • Pregnant women - Premature delivery - Low birthweight in infants - Higher infant mortality - Impaired cognitive function Vegetarians and vegans Chronic renal failure patients - Those treated with dialysis they lose large amounts of iron Gastro inflammation - Crohn’s disease and coeliac -> iron malabsorption Colorectal cancer patients - Lots of blood loss Types and best sources of iron • Two types: - Heme: from animal products and has higher and more uniform absorption - Non- heme: from plant foods: such as dried beans, dark green leafy vegetables, legumes etc. Bioavailability of iron • • Inhibition: - Phytic acid (found in legumes, nuts) inhibits non-heme - Milk proteins, egg protein, albumin and other animal products inhibit iron absorption - Ca2+ for both heme and non-heme Enhancers - Vitamin C (both synthetic and dietary) - Citric, malic and lactic acids, vit A, beta-carotene enhance non-heme iron absorption - Meat enhances non-heme iron absorption Management of IDA • Dietary therapy - Increasing iron intake - Recommended intakes • Oral Therapies- iron supplements: - in adults is 100–200 mg of elemental iron daily or in 2 to 3 divided doses - doses for children are 3–6 mg/kg/day of elemental iron Intravenous (IV) iron therapy Intramuscular (IM) iron therapy - Painful and associated with permanent skin staining - Discouraged Iron polymaltose • • • - • An average total-dose infusion of iron polymaltose (sufficient to replenish iron stores, commonly 1000 mg–2500 mg for adults) Iron sucrose - patients with chronic kidney disease who are having an erythropoietin-stimulating agent and react systemically to iron polymaltose - It cannot be given as a single total-dose infusion (due to the rate of release of vasoactive iron) but is instead given as multiple smaller (commonly 100–200 mg) IV doses.