Lecture 16 B1 Flashcards
Blood composition and function
The average blood volume is 5L. What role does arteries and veins play in the circulatory system relating to Bp
Arteries have smooth muscle walls that maintain blood pressure in a directional flow from lungs to tissue to organs.
Vein pressure is lower because it is not elastic, with one way valves stopping back flow.
What is blood pressure important for and what is the right level
Even and efficient flow through small capillaries (require blood to be forced through). The right level is low enough not to cause capillary leaking but high enough to avoid coagulation
What is the relationship between blood pressure & volume and bp & the size of vessels
Blood volume must be maintained to maintain pressure.
Smaller vessels have increased pressure but a small volume while large vessels have high volume but low pressure.
What is systolic bp
the arteries squeezed at its greatest, the highest blood pressure you can get when your heart beats
What happens if your bp gets too high (hypertension) because of hardening of arteries providing too much resistance
At the risk of thrombolic diseases- leads to reduced flow and unwanted coagulation
What happens if your bp is too low
fainting
Name the 6 major components of blood
Cells, proteins, lipids, electrolytes, vitamins & hormones and glucose
Describe the structure of haemoglobin
4 haem molecules containing one Fe2+ ferrous form of iron.
How does haemoglobin transport oxygen and CO2 in blood (pressure)
The partial pressure of oxygen in the lungs is 100 mmHg and O2 freely binds to Fe2+ but as this pressure drops in the tissue, O2 dissociates and is replaced by CO2
CO and CN can displace O2. What is the colour of the blood related to the poisoning as well as the normal colours of blood
O2 is bright red, CO2 is dark red, C monoxide is cherry red and CN is pink
Name the five most abundant proteins in blood in order of abundance
Albumin, Fibrinogen, Immunoglobulins, Complement, Coagulation proteins
What is albumin
maintains collodial osmotic pressure (maintains hypertonicity) but also binds and transports many small molecules and proteins
What is fibrinogen
protein cleaved by the enzyme thrombin to form cross linked fibrin that forms the blood clot
What is Immunoglobulins
Antibodies responsible for immunity, made by plasma cells.
What is complement
inactive until cleaved (zymogens) proteins that tag invading organisms so they can be digested by phagocytes
What are coagulation proteins/factors
13 proteins that initiate the cleavage of fibrinogen to fibrin to form the clot.
Describe the composition of centrifugation of blood
Plasma: viscous liquid fraction of uncoagulated blood. Buffy coat containing WBC and platelets
Packed RBC
What is serum (derived from plasma after clotting)
Straw coloured liquid that remains after coagulation without cells or fibrinogen (tit formed the insoluble fibrinogen clot).
What are myeloid cells
Cells that provide you with innate immunity and phagocytose. They have receptors that bind immune complexes.
Name 4 myeloid cells
Neutrophiles, monocytes (become macrophage), Basophils and Eosinophils
What are lymphoid cells
B lymphocytes and T lymphocytes
What are platelets
cells that link together to form a clot and release factors that regulate homeostatic tissue repair
What ion is essential to coagulation factors
Ca2+
What is Haemophilia and what causes it
missing coagulation factor, (factor 8 most popular)
How can you find if a patient has multiple myeloma
serum electrophoresis reveals elevated level of monoclonal antibody
What is main functions of electrolytes in the blood
Isotonicity and buffering, regulating pH as well as regulation of cell membrane ion channels
what is the origin of blood cells (Haematopoeisis)
Pluriopotent human stem cell with CD34 cell surface marker give rise to two multipotent stem cells- myeloid (innate) or lymphoid (adaptive) progenitors
What do Myeloid progenitors give rise to
-> RBC, platelet producing Megakaryocyte, mast cell, Myeloblasts (produce all myeloid cells)
What do Lymphoid progenitors give rise to
B or T lymphocytes or natural killer cell. T lymphocytes produce plasma cell.
What are the stimulating factors given to speed up recovery for leukemia patients that had a autologous human stem cell transplant
GM-CSF: stimulates production of the myeloid lineage and GCSF: stimulates production of granulocytes but also acts to mature neutrophils and EPO: drives production of RBC
What is the classical complement pathway
Triggered by antibody IgM or IgG binding to antigen. C1 complex on the surface of bacteria cleaves C4 and C2 which forms C3 convertase (C2aC4b)
What is the alternate complement pathway
Complement C3 is activated by being close to the surface of the microbe, activating another type of C3 convertase
What is the purpose of Complement pathways
to make C3 convertase complexes that irreversably coat microbes - opsonisation and this allows macrophages & neutrophils to identify these bacteria as they have complement receptors that bind complement and initiate phagocytosis
What is the lectin activation complement pathway
Lectins- are proteins in blood that bind to unusual carbohydrates on microbes. Complement condenses on these bound lectins.
What is the end stage complement?
the surface bound convertases activate complement C5-9. with the C5b, 6, 7, 8,9 forming the lytic pore- membrane attack complex.
What are anaphylotoxins
These are small polypeptides (C5a, C4a and C3a) from the cleavage of the larger complement proteins that chemoattract
phagocytes.
What are virulence factors
Proteins that inhibit the complement cascade
What are the two pathways that activate factor X in coagulation pathway and what causes them
Extrinsic (tissue damage) or Intrinsic (surface contact)
What factors are in the Extrinsic pathway that activate factor X
Factor 5 and 7 and tissue factors combine
What factors are in the Intrinsic pathway that activate factor X
Factor 12,11,9,8 lead to cleavage of factor x
What does the cleavage/activation of factor X in the coagulation pathway achieve
Factor X activates thrombin from prothrombin. Thrombin cleaves fibrinogen into fibrin to form cross links = blood clot
What cleaves blood clots (thrombolysis)
Plasmin, produced by plasminogen. Plasminogen is a protease activated by tissue plasminogen activator (TPA) or streptokinase.
What are the actions of anti coagulants and give examples
block thrombin, such as heparin and warfarin
What mineral is important for coagulation
calcium
What step do parasites that rely on blood for food target
the thrombin step of cleaving fibrinogen to fibrin
What is thrombosis
unwanted clotting
