Physiology Flashcards
Which type of blood cell can come from either myeloid or lymphoid progenitor cells?
Dendritic cells
The common myeloid progenitor (CMP) cell can develop into the megakaryocyte erythroid progenitor (MEP)- what mature cells can these differentiate into?
Platelets or erythrocytes
The common myeloid progenitor (CMP) cell can develop into the granulocyte macrophage progenitor (GMP)- what mature cells can these differentiate into?
Granulocytes (neutrophils, basophils, eosinophils) and monocytes (macrophages)
Other than dendritic cells, what mature cells can common lymphoid progenitor cells differentiate into?
B cells, T cells or natural killer cells
At what stage in erythropoiesis is the nucleus lost?
Just before becoming a reticulocyte (late normoblast phase)
What do reticulocytes contain than mature erythrocytes do not?
RNA
Which cell is this describing: a segmented nucleus (polymorph) which has neutral staining granules?
Neutrophils
Which cell is this describing: a bi-lobed cells with bright orange/red granules?
Eosinophils
Which cell is this describing: contains large deep purple granules obscuring the nucleus?
Basophils
What chains is adult haemoglobin composed of?
2 x alpha and 2 x beta chains
What chains is foetal haemoglobin composed of?
2 x alpha and 2 x gamma chains
Which of the following does oxygen bind to: Fe2+ or Fe3+?
Fe2+
When hypoxia is sensed by the kidneys, what is produced in order to stimulate erythrocyte production?
Erythropoietin
Where does destruction of erythrocytes normally take place?
Spleen
When an erythrocyte is destroyed, a haem group is broken down into what two things?
Iron and bilirubin
In erythrocytes, glutathione reacts with hydrogen peroxide to form water and GSSG- what is the rate-limiting enzyme in this process?
Glucose-6-phosphate dehydrogenase
How is the majority of CO2 transported in the blood?
As bicarbonate
In what direction does foetal haemoglobin shift the oxygen-haemoglobin dissociation curve?
To the left
Shifting the oxygen-haemoglobin dissociation curve to the right suggests what?
There is less oxygen bound to haemoglobin, and more given to the tissues
Shifting the oxygen-haemoglobin dissociation curve to the left suggests what?
There is more oxygen bound to haemoglobin, and less given to the tissues
What must happen to the pH for the oxygen-haemoglobin dissociation curve to shift right?
Decreased
What must happen to the 2, 3-DPG for the oxygen-haemoglobin dissociation curve to shift right?
Increased
What must happen to the temperature for the oxygen-haemoglobin dissociation curve to right?
Increased
What must happen to the pH for the oxygen-haemoglobin dissociation curve to be shifted left?
Increased
What must happen to the 2, 3-DPG for the oxygen-haemoglobin dissociation curve to be shifted left?
Decreased
What must happen to the temperature for the oxygen-haemoglobin dissociation curve to be shifted left?
Decreased
How much iron is absorbed per day? Where is most iron absorbed?
1mg, mostly absorbed in the duodenum
Where can iron be taken to once it has been absorbed?
To the liver for storage or to the bone marrow to make haem
How much iron is lost per day?
1mg
What is iron bound to in the plasma?
Transferrin
What are some examples of drugs which may limit the absorption of iron?
PPIs and calcium supplements
What molecule is responsible for facilitating iron export from cells and passing it onto transferrin for transport elsewhere?
Ferroportin
What molecule is the major negative regulator of iron uptake, that works by degrading ferroportin so iron is effectively ‘trapped’ inside cells?
Hepcidin
If there is plentiful iron, what happens to the levels of hepcidin and ferroportin?
Increased hepcidin, decreased ferroportin
If there is iron deficiency, what happens to the levels of hepcidin and ferroportin?
Decreased hepcidin, increased ferroportin
Transferrin will only bind to iron in what state- Fe2+ or Fe3+?
Fe3+
If someone is in iron overload, what happens to transferrin saturation?
Increased
If someone is iron deficient, what happens to transferrin saturation?
Decreased
What molecule is a spherical intracellular protein that stores many Fe3+ ions?
Ferritin
Why is an increase in serum ferritin not specific for iron overload?
It is an acute phase protein
What happens to the level of serum ferritin in iron deficiency?
Decreased
What happens to the level of serum ferritin in iron overload?
Increased
What is the lifespan of a red blood cell?
120 days
What is the lifespan of a platelet?
7-10 days
What is the lifespan of a neutrophil?
7-8 hours
Which type of lymphocyte is responsible for mediating humoral immunity?
B cells
Which type of lymphocyte is responsible for mediating cell mediated immunity?
T cells
Which type of lymphocyte has anti-viral/anti-tumour properties?
Natural killer cells
What are blast cells? Where are these located in adults?
Nucleated precursor cells located in the bone marrow of adults
What is the name of the platelet precursor cell?
Megakaryocyte
What is the name of the immediate erythrocyte precursor cell?
Reticulocyte
What are myelocytes?
Nucleated precursor cells between neutrophils and blasts
Embryonically, haemopoietic stem cells originate in which germ layer?
Mesoderm
Where does haemopoiesis take place in adults?
In the bone marrow of the axial skeleton, pelvis and long bones
What is the only lymphoid cell that can be recognised down a microscope?
Plasma cell
What is the only investigation that can be used to differentiate between B, T and natural killer cells?
Immunophenotyping
The presence of Howell-Jolly bodies suggests what pathology?
Hyposplenism
What is meant by the term hypersplenism?
Splenomegaly, fall in one or more cellular components of blood, correction of cytopenias by splenectomy
What is meant by primary haemostasis?
The formation of a platelet plug
What is meant by secondary haemostasis?
The formation of a fibrin clot
What is fibrinolysis?
The breaking down of a fibrin clot to avoid occlusion of a blood vessel
Platelets are formed in the bone marrrow from which precursor cells?
Megakaryocytes
When there is endothelial damage in a vessel, collagen is exposed and produces what factor, that platelets bind to?
Von-Willebrand’s factor
The process of platelets sticking to exposed collagen via binding with Von Willlebrand’s factor is known as what?
Platelet adhesion
The process of platelets which are already bound to exposed collagen producing chemicals to attract more platelets to the site of injury is known as what?
Platelet aggregation
What is a vascular cause for failure of primary haemostasis?
Loss of collagen with ageing
What are some platelet causes for failure of primary haemostasis?
Reduced number or reduced function of platelets
What is the Von-Willebrand’s factor cause for failure of primary haemostasis?
Inherited low levels
What is the most common cause of reduced function of platelets?
Anti-platelet and NSAID drugs
What are some potential consequences of failure of primary haemostasis?
Spontaneous bruising/purpura, mucosal bleeding, intracranial/retinal haemorrhages
What is the screening test for primary haemostasis function?
Platelet count
What process starts the extrinsic pathway of the coagulation cascade?
Tissue factor activates factor VII
In the common coagulation pathway, tissue factor and factor VII activate which other clotting factors?
V and X
In the common coagulation pathway, factors V and X active which clotting factor to form what?
Prothrombin to form thrombin (factor II)
In the common coagulation pathway, factor II (thrombin) is responsible for activating what clotting factor?
Fibrin (factor I)
When thrombin (factor II) is first generated, what factors does it activate in order to amplify the process?
VIII, IX, XI and XII
In the common coagulation pathway factors VIII, IX, XI and XII get reactivated by thrombin and work to activate which other clotting factors?
V and X
Which clotting factors are involved in the intrinsic pathway and in what order do they activate each other?
XII - XI - IX - VIII
Which electrolyte is a common co-factor in activating a lot of clotting factors in the coagulation cascade?
Calcium
Is deficiency of a single clotting factor more likely to be inherited or acquired?
Inherited
Is deficiency of multiple clotting factors more likely to be inherited or acquired?
Acquired
Most clotting factors are produced where?
In the liver
What is the best screening test to assess the function of the extrinsic pathway, i.e. tissue factor and factor VII?
Prothrombin time (PT)
What is the best screening test to assess the function of the intrinsic pathway, i.e. factors VIII and IX?
Activated partial thromboplastin time (APTT)
If all clotting factors are low, which will be increased- PT, APTT or both?
Both
If only factors VIII or IX are low, which will be increased- PT, APTT or both?
APTT
What molecule is responsible for converting fibrin into fibrin degradation products in fibrinolysis?
Plasmin
How is plasmin formed?
Plasminogen is converted to plasmin via tissue plasminogen activator (tPA)
Fibrin degradation products are measured in the lab as what?
D-dimers
Which naturally occurring anticoagulant is responsible for turning off thrombin and some other clotting factors directly?
Anti-thrombin III
Which naturally occurring anticoagulant is responsible for turning off factors V and VIII?
Protein C
What is a co-factor that helps out protein C?
Protein S
When haemostasis has been achieved, thrombin binds to thrombomodulin and this has what effect?
Activates protein C and switches off haemostasis
