Blood System(1) Flashcards
What does blood transport around the body?
Nutrients, gases, hormones & cells
What is the type of transport blood performs called?
Mass transport - vehicle of long distance
What does blood maintain?
Homeostasis of osmotic pressure, temperature & pH
What are some of the system’s blood is part of?
Cardiovascular
Respiratory
Immune
Etc
3 main functions of blood
Protection
Regulation
Transportation
What does blood protect?
Protects against blood loss and infections by clotting and immune system
Define hematocrit
Packed cell volume of blood - the rest is plasma
What are the hematocrits for women and men?
Women 42%
Men 45%
What % of total body weight is blood?
8%
What is the buffy coat and what % of blood is it?
Platelets and leukocytes = less than 1% of blood
What is 55-58% of blood?
Plama
Where is blood taken from?
Veins
What is serum?
Liquid from coagulated blood
What treatments are important for people with leukemia & dengue?
Platelets important for coagulation
What does plasma consist of?
90% water that have dissolved substances
6% plasma proteins
What is dissolved in plasma?
Inorganic solutes
Organic constituents = mostly plasma proteins
Other organic substances = water products, dissolved gases & hormones
Name 3 plasma proteins
Albumin
Globulin
Fribrinogen
What is the role of plasma proteins?
Carry out the functions of plasma
What is the role of albumin?
Carrier of lipid soluble substances
Maintain osmotic pressure = when increased vascular permeability, albumin comes out and water comes out
What is the role of globulins?
Alpha & beta = transport water insoluble substances incl clotting factors
Gamma = antibodies
What is the role of fibrinogen?
Inactive precursor of fibrin
Where do platelets come from?
Megakaryocytes are a special type of bone marrow cells that give rise to thrombocytes (platelets)
Name polymorphonuclear cells
Neutrophils & eosinophils
Name mononuclear cells
Monocytes
Lymphocytes
What are the RBC maturation stages?
Pluripotent stem cell
Myeloid stem cell = partially differentiated
Erythroblast = nucleated
Reticulocyte = no nucleus but organelles
Erythrocyte = mature RBC (lots of Hb)
Name key erythrocyte enzymes
Glycolytic enzyme
Carbonic anhydrase
What type of enzymes remain in a mature erythrocyte?
Non-renewable enzymes
What features does a erythrocyte have?
Flat shape = large SA for diffusion
Flexible membrane = squeeze through capillaries
Haemaglobin content suited for O2 transport
Describe haemaglobin structure
Haem group = pigment
Globin group = 4 polypeptide chains (2α2β)
Each globin chain binds 1 haem group
Each haem group has iron, which binds O2
Describe the binding of oxygen to iron
Binding is loose and reversible = depends on the partial pressure of oxygen
Change in pH can shift the binding affinity of oxygen to haem
What happens when blood pO2 increases?
More HbO2
When blood pO2 decreases = O2 released from HbO2
When does Hb pick up CO2?
When partial pressure of CO2 increases in systemic tissues
What is it called when CO2 binds Hb?
Carbamino Hb
Where is CO2 binding site on haemaglobin?
Different binding site to oxygen
Instead binds to globin not iron
What form is 70% of carbon dioxide transported as?
Bicarbonate (HCO3-)
Why do RBCs have short life spans?
No nucleus so no DNA/RNA = cannot synthesize new proteins or divide
What is erythropoiesis?
Generation of new RBCs in bone marrow
Erythropoiesis occurs in the bone marrow
Where do old RBC die?
Spleen (network of capillaries)
How does the body know to increase erythropoiesis?
Reduced oxygen delivery to kidney stimulates kidney to secrete erythropoietin into the blood.
EPO stimulates erythropoiesis by red bone marrow
More circulating RBCs increase O2-carrying capacity
Increased O2-carrying capacity relieves initial stimulus that triggered EPO secretion
What happens when there is hemmorhage or blood loss?
Reticulocyte levels increase = peaks at 4-7 days after 1st episode of blood loss
How long after blood loss do reticulocyte levels become normal?
2 weeks
What happens if there is a second blood loss episode within 5 days?
Reticulocytes remain high
What is the normal level of reticulocytes?
0.5% - 2.5%
What is EPOGEN and its functions?
Epogen = recombinant EPO (synthetic)
Used to boost RBC production in patients with suppressed eythropoietic activity
Examples of when to use Epogen
Surgery
Chemotherapy for leukemias which affect RBC production and function
Dialysis patients
Doping
What breaksdown Hb?
Aged and damaged RBCs are engulfed by macrophages of liver, spleen, and bone marrow
Hb broken down into Heme and Globin
What happens to globin when it is broken down?
Globin protein is broken down into amino acids, which are taken up into the blood
What happens to heme when it is broken down?
Iron is stored as ferritin, bound to transferritin & released from liver into the blood for erythropoisis
Billirubin is taken up from blood by liver, secreted into intestine in bile & metabolized into stercobilin by bacteria > excreted by feces
Where do food nutrients needed for erythropoiesis go?
They are taken up into the blood from intestine
Examples: iron, Vit B12, protein & folic acid
Why do babies get jaundice?
Their liver is not developed enough to remove the bilirubin from the blood
Define anemia
Reduction below normal capacity of blood to carry oxygen
Due to reduction of RBC and/or reduction of Hb function
Anemia symptoms?
Blood oxygen levels cannot support normal metabolism leading to:
Fatigue = not enough O2 to tissues
Paleness
Shortness of breath = low O2
Chills
What is the opposite of anemia called?
Polycythemia = too many RBCs & elevated hematocrit
What causes primary polycythemia?
Vera (genetic) causes bone marrow to produce more precursor blood cells leading to increased RBC production (myeloproliferative cancer)
What causes secondary polycythemia?
High altitude = low O2
Obstructive sleep apnea = low O2 causing more EPO
Other heart/lung diseases which cause low O2
What happens to hematocrit in dehydration?
Lower plasma levels so hematocrit is a higher percentage
Describe thin vs thick blood
Anemia has less RBCs so less viscous = less platelets so more bruising
Polycythemia has more RBCs so higher blood pressure and more blood clots = more viscous
What are the groups of leukoctyes?
Polymorphonuclear granulocytes
Mononuclear agranulocytes
Roles of the lymphocytes
Neurtorphils = engulf and destory bacterial intracellularly
Eosinophils = associated with allergic conditions & parasite infection
Basophils = synthesize & store histamine and heparin
Monocytes = phagocytosis
Lymphocytes provide specific immune defense
What controls rate of granulocyte production?
Granulocyte colony-stimulating factors (GCSF)
Stimulates increased replication & release of granulocytes - esp neutrophils from bone marrow
Leukocytes are produced at varying rates depending on the body’s changing needs
