Blood Flashcards
What is the process called by which new blood cells are formed?
hematopoiesis
What is the lifespan of a red blood cell?
120 days
What is the lifespan of a circulating platelet?
7-10 days
What percentage of blood is RBCs?
45%
What percentage of blood is plasma?
55%
What percentage of blood is white blood cells and platelets?
Less than 1%
what else can a hemocytoblast be called?
hematopoietic stem cell
What stem cells can a hemocytoblast form?
lymphoid stem cell and myeloid stem cell
What do erythrocytes lack that many other cells have?
mitochondria and a nucleus
List possible end products from a myeloid progenitor cell
Platelets, erythrocytes, macrophages, granulocytes
What are the three granulocytes?
neutrophil, eosinophil, basophil
What cell comes between the myeloid progenitor cell and the devlopment of a neutrophil?
myeloblast
What type precursor cell to erythrocytes has no nucleus and enters the circulation before later maturing into an erythrocyte?
reticulocyte
What large bone marrow cell that comes from myeloid progenitor cells is responsible for the production of platelets?
Megakaryocyte
What do monocytes develop into, allowing them to enter peripheral tissues?
Macrophages
What comprises the axial skeleton?
Skull, ossicles of the middle ear, hyoid bone, rib cage, sternum, vertebral column
What can common lymphoid progenitor cells develop into?
T cells, B cells and natural killer cells
Where does the production of red blood cells begin in utero?
yolk sac
In the fetus where are the predominant sites of hematopoiesis?
Second trimester- liver
From 7 months- bone marrow
Describe how the distribution of red marrow changes with age after birth.
In the first 4 years- almost all marrow cavities contain red marrow
In adults- red marrow is limited to the axial skeleton and long bones
What is red marrow replaced with as we age
yellow marrow (fat)
what does EPO stand for?
erythropoeitin
Where is erythropoietin produced?
The kidney
What is the most abundant leucocyte?
neutrophil
How many alpha and beta chains does adult haemoglobin contain?
2 alpha, 2 beta
What type of ring is present in the haem group?
porphyrin ring
Where do T cells mature?
The thymus
What is a T cell referred to when it has not yet encountered its specific antigen?
naive T cell
What do naive T cells with CD8 become?
cytotoxic T cells
What do naive T cells with CD4 become?
T helper cells
What do cytotoxic T cells release?
Cytotoxic granules
Gives examples of T helper cell subtypes
Th1 cells, Th2 cells, Th17 cells and regulatory T cells
What do T helper cells release?
cytokines
Where do B cells mature?
The bone marrow
What do plasma cells produce?
antibodies
What types of memory cells are there?
Memory T cells and memory B cells
Do all B cells require T cells to produce antibodies?
Most but not all. Ones that do not require the presence of T cells are called T-independent B cells
Where can you find the macrophages that break down old and damaged erythrocytes?
Spleen, Liver, Bone marrow
What is haemoglobin first broken down into by macrophages?
heme and globin
What is globin broken down into?
amino acids
What drives erythropoeisis?
hypoxia
Where is intrinsic factor produced?
the stomach
What type of cells produce intrinsic factor?
parietal cells
What does intrinsic factor bind to?
B12
In what part of the GI tract is the intrinsic factor bound to B12 absorbed?
The ileum
What does B12 bind to in the circulation?
transcobalamin I and II
Fe2+ leaves the enterocyte via what transporter?
ferroportin
On, leaving the enterocyte and entering the circulation, what is Fe2+ converted into?
Fe3+
Once in the circulation after absorption from the diet, what does Fe3+ bind to?
transferrin
Describe the roles of eosinophils
Role in protection against parasites, roles in inflammation and allergic response
Describe the role of neutrophils
Phagocytic, release chemotaxins and cytokines
What is chemotaxis?
Movement in response to chemical stimulation
How do platelets bind to collagen?
GP1a
How do platelets bind to VWF?
GP1b
What is the word for when a platelet is activated and releases its contents?
Degranulate
What percentage of blood plasma is water?
90%
What is serum?
Plasma without clotting factors
Where is albumin produced?
The liver
What forms the bridge between GPIIb/IIIa receptors on platelets, binding them together?
fibrinogen
What is primary haemostasis?
Formation of the primary platelet plug
What is secondary haemostasis?
Coagulation cascades
What are the 5 steps of haemostasis?
- Vascular spasm
- Platelet plug formation
- Coagulation
- Clot retraction and repair
- Fibrinolysis
What is vascular spasm?
Endothelin- Damaged epithelial cells release endothelin-> endothelin causes contraction of smooth muscle -> vasoconstriction
Myogenic mechanism- direct injury to smooth muscle causes contraction
Nociceptors- stimulation causes contraction of smooth muscle
What helps to keep platelets inactive normally?
Endothelial cells secrete nitric oxide and PGI2
What substances that are released by activated platelets cause vasoconstriction?
Thromboxane A2 and serotonin
What is the function of prothrombin activator?
Converts prothrombin into thrombin
What does thrombin do?
Converts fibrinogen into fibrin
Describe the changes in solubility in plasma between fibrinogen and fibrin
Fibrinogen- soluble in blood plasma
Fibrin- Insoluble in blood plasma
What does the cross-linking of fibrin strands create?
The fibrin mesh
Describe how the endothelial cells on either side of a section of damaged blood vessels get brought closer together?
Platelet contraction
What converts plasminogen into plasmin?
Tissue plasminogen activator
What does plasmin do?
Degrades fibrin mesh
What is oedema?
Excessive accumulation of serous fluid in the intercellular spaces of tissue
What type of antibody is capable of transplacental passage from mother to fetus?
IgG
Give two examples of agranulocytes
Monocytes and Lymphocytes
Put the granulocytes in order of most to least abundant
Neutophils, eosinophils, basophils
Which is more abundant- lymphocytes or monoctyes?
Lynphocytes
What is the most common white blood cell?
Neutrophils
Describe the nucleus of a neutrophil
Multi lobed
What three types of cytoplasmic granule do neutrophils contain?
primary, secondary and tertiary granules
Give an example of a primary granule found in a neutrophil
Lysosomes
Describe the action of secondary granules in the neutrophil
secrete substances that mobalise inflammatory mediators
In a parasitic infection which granulocyte would you expect to see an increase in number of ?
Eosinophils
Describe the nucleus of an eosinophil
bi-lobed
Describe the apppearance of the cytoplasmic granules of an eosinophil
Large red granules with crystalline inclusions
Lozange shaped granules with crystalline cores
How do eosinophils effect mast cell secretion
Inhibit it
What effect do eosinophils have on histamine?
Neutralise histamine- restrict inflammatory responses
Describe the nucleus of basophils
bi-lobed
What do the granules in basophils contain
histamine
What do basophils release in response to allergens?
histamine
What are basophils the circulating from of?
The tissue mast cell
Can you tell different lymphocytes apart on H&E stained section?
Nope. They all look the same
What is the main role of natural killer cells?
maily kill virus infected cells
What is the tole of T suppressor cells?
Suppress T helper cells and therefore suppress the immune response
What is the role of T cytotoxic cells?
Kill previously marked target cells
Describe the nucleus of monocytes
Reniform
What can monocytes differentiate into?
tissue macrophages-everywhere Kupffer cells-liver Osteoclasts-bone Antigen presenting cells-everywhere Alveolar macrophages-lung
What blood types can someone who has type A blood donate to?
A and AB
Which blood type has no antigens?
O-
What type of antibodies will someone with type A blood have?
Anti-B antibodies
Will someone with AB blood have any anti A or anti B antibodies?
No
Hemolytic disease of the newborn occurs when the mother and baby have what blood types?
Mother- Rh-
Baby-Rh+
Antibodies produced by the mother can attack the baby’s red blood cells
Who can someone who is Rh negative donate to?
Someone who is either Rh positive or negative
Who can someone who is Rh+ donate to?
Someone who is also Rh positive but not anyone who is Rh negative
What are the possible geneotypes for someone who has type A blood?
AA or AO
When a platelet is activated describe how it changes shape
Surface area increases
With regards to the GPIIb/IIIa receptors, what changes occur after the platelet is activated?
Number of GPIIb/IIa receptors increases
What causes the increase in affinity for fibrinogen after a platelet is activated?
An increase in the number of GPIIb/IIa receptors
What is firbinogen a precursor to?
Fibrin
What is atherogenesis?
the formation of fatty deposits in the arteries
Describe how a platelet can be activated
Thrombin- activates platelets( and cleaves fibrinogen into fibrin)
Thromboxane A2- activates platelets
Collagen- GP6 receptor binds to collagen, activating platelets
ADP
What receptors do platelets have for collagen?
Glycoprotein VI
Glycoprotein Ia/IIa
What does COX stand for?
Cyclooxygenase
What is the role of COX-1 in platelets?
Converts arachidonic acid into prostaglandin H2 and then thromboxane A2
Which cyclogenoxygenases are involved in prostacyclin production in endothelial cells?
COX-1 and COX-2
What is are the precursors to prostayclins produced in the endothelial cells?
Arachidonic acid and prostaglandin H2 (Prostaglandin H2 comes after arachidonic acid)
Describe the role of COX-1
Thromboxane A2 mediated platelet aggregation
What does COX-2 mediate?
Prostacylin production
What does prostacyclin inhibit?
Platelet aggregation
What type of receptors are P2Y1 and P2Y12?
G-protein coupled receptors
What binds to P2Y1 and P2Y12?
ADP
Binding of ADP to P2Y1 receptors has what effect?
Initiates platelet activation
Binding of ADP to P2Y12 receptors has what effect?
Amplification of platelet activation via reducing inhibition of activation
What type of granules release ADP when a platelet is activated?
Dense granules
What receptor does thrombin bind to?
PAR-1
Describe the position of aminophospholipids in a resting platelet
Aminophospholipids are on the inner layer of plasma membrane
What ion is released from inracellular stores when a platelet is activated?
CA++
What does Ca++ activate in the platelet?
scramblase
What does Ca++ inhibit in the platelet?
translocase
How does the position of the aminophospholipids in the platelet change due an increase in Ca++?
Causes aminophospholipids to be on the outher layer of the membrane
What enzyme forms on the surface of the platelet as a result of increased Ca++?
prothrombinase
What is the other name for clotting factor X?
prothrombinase
What is clotting factor II?
Thrombin
What type of cell releases tissue plasminogen activator?
endothelial
What is fibrin broken down by plasmin into?
fibrin degradation products
What does P-selectin allow platelets to bind to?
white blood cells
