Blood composition and function Flashcards
What is arterial pressure
When the blood is under considerable pressure
* left ventricle in full contraction (cystolic)
* maintained by elastic vessel walls that contain abundance of smooth muscle
What does blood do
Blood provides a one-way pressurised system for the transport of oxygen, proteins, glucose, lipis and essential ions
Why is venous pressure lower than arterial pressure
Because veins are not elastic; one way valves are required to prevent back flow.
What does blood pressure ensure
- Even and efficient flow through small cappilaries
- low enough to prevent capillary leakage but high enough to avoid coagulation
What does the heart do
- Takes blood from lungs (that are fully oxygenated) and sents through into left ventricle
- Pumps blood through arterias
- sends blood through all tissues
Oxygen transport
Oxygen is carried from lungs to tissues by haemoglobin (major protein in RBC)
RBC make up __% of the total blood volume and haemoglobin constitutes __% of the RBC’s dry weight.
45% and 96%
Each haemaglobin molecule contains…
4 haem molcules each containing 1 iron atom in the ferrous form (Fe2+)
What is the function of blood
A one-way pressurised system for the transport of oxygen, proteins, glucose, lipids and essential ions all required for normal cell function.
What does a LBP mean
Cant push blood efficiently
What does a HBP mean
The heart is pumping much harder , the arteries are not as elastic
What are the major components of blood
- Cells
- proteins
- lipids
- electrolytes
- vitamins, hormones
- glucose
What are the different cells involved with blood
Erythroid, myeloid and lymphoid
What is blood separation by electrophoresis
A ommon means of separating blood proteins using an electrial field. Serum electrophoresis separates serum into 5 major protein fractions - abumin, a1, a1, B and y fractions.
What 5 major protein fractions does serum electrophoresis separate into
Serum electrophoresis separates serum into 5 major protein fractions - abumin, a1, a1, B and y fractions.
What are different proteins part of the blood
Albumin, fibrinogen, haemaglobin, immunoglobins (the major ones)
What is albumin
It functions primarily to maintain colloidal osmotic pressure but also binds and transports many small molecules and proteins. Albumin is a major binder for pharmaceutical drugs - affecting their bioavailability
What percentage of total blood proteins are albumin
50%
What is fibrinogen
The second most abundant protein. This protein is cleaved by the enzyme thrombin to from cross-linked fibrin that forms the blood clot.
What are immunoglobins
They are found in the Y fraction (serum electrophoresis) and are responsible for immunity. Ig proteins are produced by plasma cells, a form of B lymphocyte.
What percentage of total blood proteins are immunoglobins (Ig)
~10%
What are complemtn (c’) proteins
A group of zymogens (inactive until cleaved) essential for phagocytosis and innate immunity. It coats invading organisms so they can be digested by phagocytes.
How many components of Complement are there, and which one is the most abundant protein
9 - most abundant is C3
What are coagulation proteins
A set of 13 proteins that initiates the cleavage of fibrinogen to fibrin to form the clot. Thrombin is the central enzyme that does this.
What is thrombin
What is the central enzyme that cleaves fibrinogen?
Upon low speed centrifugation, what three components does blood separate to
- packed red cells (40%)
- buffy coat (10%) containing white cells
- plasma (50%) containing soluble proteins, lipids and centrifugation.
What is plasma
The viscious liquid fraction of uncoagulated blood.
* Where lipids are digested.
* All soluble proteins are present.
* Includes small celsls involved in coagulation.
* Homeostasis
why is it the particular colour
What is serum
Straw coloured liquid that remains after coagulation. It is this ccolour but if you’ve just had a fatty meal then it is cream coloured because of the ingested lipids.
Why is fibrinogen absent from serum
It has formed the insoluble fibrin clot.
What are coagulation factors
13 proteins cleaved in an ordered cascade resulting in fibrinogen to fibrin.
What are the three types of blood cells and their functions
- Erythrocytes - carries o2
- Leukocytes - essential for immunity
- Platelets - coagulation and tissue repair
What is haematapoiesis
All blood cells begin life as a single pluripotent human stem cell (HSC) found mainly in the bone marrow. It is characteristed by teh CD34 cell surface marker atigen used to isolate these cells.
Where are CD34+ most abundant
In placental cord blood.
What does CD34+ give rise to
Two multi-potent stem cells - myeloid or lymphoid progenitors
What is a myeloid progenitor
Can give rise to erthryocytes, a platelet producing megakaryocytes, mast cells or myeoblasts.
What is the function of myeloid cells
Provide you with innate immunity and phagocytosis. These cells have a range of receptors that bind immune complexes. Microbes are rapidly phagocytosed and killed once they have been oponised by complement proteins.
What can myeoblasts further differentiate into
Either neutrophils, basoophils, eosinophils or monocytes.
What is a lymphoid progenitor
Differentiates into B lymphocytes or T lymphocytes.
What does a immature T lymphocyte differentiate into
CD4 and CD8
What are the three important factors that drive haematopoiesis
GM-CSF, EPO and G-CSF.
What is GM-CSF produced from
Produced from macrophages, T cells, endothelial cells and fibroblasts.
What does GM-CSF stimulate
The production of neutrophils, eosinphils, basophils and monocytes.
What is EPO produced from
Mainly by the kidney during adulthood and liver in perinatal.
What is the function of EPO
Drives the production of erythrocytes. It drives RBC to increase to increase O2 capacity.
What is G-CSF produced from
Many different cells
and the production of what
What does G-CSF stimulate
Stimulates production of granuloctes but also acts to mature neutrophils.
What is the role of GCSF and GMCSF in relation to leukemia patients
They are administered to repopulate white cells in leukamia patients following radio-ablation.
What is the role of GCSF and GMCSF in relation to leukemia patients
They are administered to repopulate white cells in leukamia patients following radio-ablation.
What is the role of GCSF and GMCSF in relation to leukemia patients
They are administered to repopulate white cells in leukamia patients following radio-ablation.
What are the three types of blood cells and their functions
- Erythrocytes - carries o2
- Leukocytes - essential for immunity
- Platelets - coagulation and tissue repair
What are the three pathways that complement can be activated
- Classical activation
- Alternative activation
- lectin
What is classical activation of complement
Initiated by antobodies binding to the surface of the microbe. C1, C2, C4 and C3 condense on the antibody to form a bound C3 convertase on the microbe surface.
What is alternative pathway to activate complement
Complement C3 is activated just by being close to the surface of the microbe. This activates another type of C3 convertase.
What is lectin activation pathway
Lectins are carbohydrate binding proteins in blood that bind to unusual carbohydrates found only on microbes. Complement condesnses on these bound lectins.
What is end stage complement
The surface bound convertases activate complement C5-9. This forms a pore that inserts into some bacterial membranes to cause lysis. This pore is called the MAC.
What are anaphylotoxins
Small polypeptides generated by cleavage of the larger complement proteins that are powerful chemoattrations that recruit and activate phagocytes to the site of infection.
What is oponisation in complement
Deposition of complement on microbes, which is essntial for phagocytosis.
What are virulence factors in complement
Many microbes produce this to inhibit the complement cascade
Blood coagulation can be initiated through what two main pathways
- Intrinic - caused by contact with surfaces
- Extrinsic - caused by tissue damage.
What is the intrinsic pathway
Factors XII, XI, IX and VIII lead to the cleavage of factor X that converts prothrombin to thrombin.
What is the extrinsic pathway
Factors VII and tissue factors combine to activate fsctor X
What does factor X activate
thrombin
What is plasminogen
A protease that is activated by tissue plasminogen activator (TPA) or streptokinase.
What is the function of TPA and streptokinase in medicine
Used to treat unwanted blood clots such as in myocardial infarct, pulmonary embolism (clot in lungs) or deep vein thrombosis (DVT). Must be adminstered early.
What is plasmin
Cleaves the fibrin clot resulting in thrombolysis.
What are two examples of anti-coagulants
Heparin and warfarin are used in medicine and many insects and parasites that rely on blood for food, and produce anti-coagulants. These block thrombin.
What is Factor X
Key enzyme common to both intrinsic and extrinsic pathways
What is calcium in relation to coagulation
It is essential at a number fo steps. If calcium is removed, blood will not clot.
