Blood Flashcards
How much blood do we have in our body?
5L
What are the phagocytic leucocytes?
1) Neutrophils
2) Eosinophils
3) Monocytes/macrophages
What are the non-phagocytic leucocytes?
1) Lymphocytes
2) Basophils
What is the appearance of a neutrophil?
Multilobed nucleus
Blue Granules
What is the appearance of basophils?
Nucleus obscured by highly granular dark staining cytoplasm
What is the appearance of eosinophils?
Bi lobed nucleus
Pink cytoplasmic granules
‘Tomato wearing sunglasses’
What is the appearance of monocytes and macrophages?
Granular (blue) cytoplasm containing white vacuoles
Nucleus has a characteristic kidney shape
What is the appearance of lymphocytes?
Large nucleus
Very little cytoplasm
Dense purple nuclei, poorly stained cytoplasm
How do neutrophils protect against pathogens and how long do they survive?
Granules contain proteolytic enzymes - break down ingested material
Non specific as dont recognise specific pathogens
Mobile, phagocytic and chemotactic (respond to chemo attractants)
Defence against bacteria and fungi
Survive for 8-10 hours make up 50-70% of leucocytes
How do basophils protect against pathogens and how long do they survive?
Basophils circulate in blood, migrate to tissues and become mast cells
Mast cells possess receptors and when they get a signal spill there granular contents into peripheral blood
Survive 1-5 days, 0-1% of leucocytes
How do eosinophils protect against pathogens and how long do they survive?
Circulate in blood and migrate to tissues where they defend against parasitic infections - certain cytokines (chemicals that affect cell division/production of immune cells) stimulate increased production of eosinophils
Survive circulating in the blood for 4-5 hours and live in tissue for 8-12 days
How do monocytes and macrophages protect against pathogens and how long do they survive?
Monocytes circulate in the blood until they migrate to tissues and become macrophages
Ingest pathogenic material, can kill intracellular organisms and are also professional APC’s
Survive circulating in the blood for 1-3 days but have a long tissue life span
What is the life span of lymphocytes?
Years
What is the appearance of plasma cells?
Granular ‘clock faced nuclei’
Basophilic cytoplasm
Whats the appearance of platelets and whats there lifespan?
No nucleus, small, blue staining
Lifespan of 20 days
What are platelets made from?
Fragments of megakaryocytes that bud off in the bone marrow before entering the blood
What is the most abundant protein in the blood?
Albumin
What is the difference between serum and plasma?
Serum = plasma - clotting factors Plasma = serum + clotting factors (+clotting inhibitor)
How do you extract serum/plasma from the blood?
Using a centrifuge
What happens when incompatible groups of blood are mixed and when does this present a problem?
Ab react with Ag on the surface of the new RBC’s causing haemolysis
This presents a problem for pregnancy and transfusion
What are the 2 main classifications of blood groups?
1) ABO
2) Rh
How is your ABO blood group classified?
Based on a carbohydrate present in the RBC membrane A = Ag A B = Ag B AB = Ag A and AgB O = no Ag
Which ABO blood group is considered a universal donor and a universal recipient?
Universal donor = O
It has no Ag for you to have Ab against
Universal recipient = AB
Blood contains Ag for neither A nor B
Why, in terms of compatibility must you considered blood type when doing a plasma transfusion (not containing RBC’s)?
Because plasma contains Ab so must make sure plasma transfused doesn’t contain Ab to your RBC’s
What are the components of an acute haemolytic reaction (which occurs when incompatible blood is transfused)?
1) Haemolysis
2) Hypotension to keep up with haemolysis
3) Kidney failure - must excrete haem and iron products from haemolysis - haemoglobinuria (free Hb in urine)
4) Systemic symptoms (fever and chills)
5) Pain in lumbar region (loins and lower back)
6) Constricting pain in chest
7) Heat sensation in transfused vein
8) DIC (disseminated intravascular coagulation)
How is youre Rhesus blood group classified?
Based on a transmembrane protein (ion channel) in RBC membrane called D antigen
Rh+ is with the Ag
Rh- is without the Ag
When does haemolytic disease of the newborn occur?
During pregnancy of a Rh+ child to a Rh- woman
Why does haemolytic disease of the newborn tend to present in second pregnancies?
1) Sensitisation - mixing of mothers and foetus blood during birth of the first child which triggers an immune response
2) In future pregnancies, Ab are able to cross the placenta and cause haemolysis in the Rh+ foetus and thus potentially lethal aneamia in the foetus
How can haemolytic disease of the new born be prevented?
Prevention with intramuscular Rh IgG (Ab that mop up Ag) injections at 28,34 and 72 hours after delivery (passive immunity) - can do an intrauterine injection if necessary
What colour do RBC’s and eosinophil granules stain?
Pink/red
What colour do DNA and RNA stain?
Blue/purple
What colour do platelets and other granules (other than eosinophil granules) stain?
Blue/purple
What are the 2 main processes involved in stemming bleeding?
1) Vasoconstriction (peptides/hormones lead to the contraction of smooth muscle cells in the vessel wall eg.
- Thromboxane (produced by platelets)
- Vasopressin (produced by anterior pituitary)
- Angiotensin 2 (precursor produced by liver)
- Serotonin (secreted by activated platelets)
2) Haemostasis
- Primary haemostasis: platelet activation and agregation
- Secondary haemostasis: coagulation pathway activation
What is a thrombocyte?
Another name for platelets
What 2 types of granules do platelets contain?
Alpha granules and dense granules
What is the shape change that platelets undergo when they are activated and what is it?
Pseudopodia
Little extensions from the membrane
Stretch and bind together and from a platelet plug
What structures/substances/enzymes are found within platelets?
Mitochondria: source of ADP for activation
Glycogen: source of energy
Canicular system (invaginations): increased surface area for activation
COX1 and TX synthase: leads to production of thromboxane
What role does thromboxane have in activating platelets?
Auto activation loop
Activated platelets produce thromboxane which further activates other platelets
What type of molecules are ADP and Thromboxane (TxA2)?
Autocrine molecules (secreted by platelets and activate platelets)
What is the ligand for aIIB1 and GPVI receptors and what are they involved in?
Collagen (important for adhesion)
What is the ligand for PAR-1, PAR-4 receptors and what kind of receptors are they and what are they involved in?
GPCR’s
Ligand is Thrombin
Involved in activation
What is the ligand for P2Y1 and P2Y12 receptors and what kind of receptors are they?
GPCR’s
ADP
Involved in activation
What is the ligand for the TP receptor, what kind of receptor is it and what is it involved in?
GPCR
Ligand is thromboxane (TXA2)
Involved in activation
What does the aIIIbB3 receptor bind and what is it important for?
Binds fibrinogen and VWF
Important for aggregation
Platelets in close proximity are able to bind to eachother via fibrinogen and VWF
From what granules in the platelet is ADP released?
Dense granules
What occurs to get the inactivated platelets to bind at the site of injury?
1) No injury - platelet circulate
2) Subendothelial matrix is rich in collagen, when an injury occurs to the endothelium this collagen is exposed and binds to receptors on the platelets activating them aswell as binding platelets at the sight of injury
3) Activated platelets release thromboxane and serotonin which cause local vasoconstriction
4) VWF present in the blood can bind platelets and collagen, fibrinogen binds inbetween platelets all helping to strengthen the platelet plug (once a2B3 receptor is activated)
5) Activated platelets also release ADP, thrombin and thromboxane which serve to recruit and activate other platelets
Although platelets can aggregate and change shape, aggregation is still reversible until what occurs?
Release of granules
What does the word limited in ‘limited proteolysis’ refer to?
The fact that the proteolysis is specific, one type of protein: one cut
What is the difference between the intrinsic and extrinsic coagulation pathways?
Intrinsic - Nothing needs to be added to the blood, coagulation is triggered by factor FXII within the blood coming into contact with a negative surface eg. glass
Extrinsic - Need to add something to the blood in order to activate it to coagulate eg. tissue factor