Introduction to Haematology Flashcards
components of the blood
plasma (55%)
RBCs
WBCs
Platelets
the densest blood component
the RBCs, least dense is the plasma
when blood is centrifuged, the “buffy coat” is composed of
the WBCs and platelets
Haemopoiesis
refers to the production of blood cells
platelet cells are referred to as
thrombocytes
the average lifespan for the various blood cells
120days for RBCs
4 hours to 10 yeas for WBCs
10-14 days for platelets
name some of the main causes of cell loss
ageing
physical injury to tissues or the cells themselves
Ischemia
Autoimmune Diseases
Apoptosis
the first site of blood production in humans
the yolk sac
after 2-7 months of development, the part of the developping baby that takes over blood production is the spleen and the liver. After nine months, the bone marrow takes over.
do all the bones in an infant/adult produce blood?
they do
in adults, some of the bones cease to produce blood as we grow, so only a selected few do(Vertebrae, ribs, sternum, skull, sacrum, pelvis, proximal ends of femur)
progenitor cells
a type of undifferentiated cell with the capacity to differentiate into specific types of cells but with a more restricted potential compared to stem cells
where can you find immature cells in the body
the bone marrow
normal peripheral blood cells
these are mature blood cells that circulate around the body
name the four main normal peripheral cells circulating the body
ERYTHROCYTES(RBCs)
LEUCOCYTES(WBCs)
PLATELETS
Granulocytes are a component of leucocytes, true or false
true
granulocytes are a type of white blood cell (leukocyte) characterized by the presence of granules in their cytoplasm, which contain various enzymes and substances involved in immune responses.
the types of granulocytes
neutrophils
basophils
Eosinophils
the most abundant types of granulocytes ae neutrophils
basophil functions
plays a role in inflammatory responses and allergic reactions. They release histamine and heparin from their granules, which contribute to inflammation and help regulate blood clotting.
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neutrophils
They engulf and destroy bacteria and other pathogens through phagocytosis and release enzymes to help kill bacteria.
it is multi-lobed( 3 to 5 lobes)
other types of WBCs apart from granulocytes are
monocytes
lymphocytes
which wbcs develop into macrophages
monocytes
anaemia
A reduction in oxygen-carrying of the blood capacity due to a
lower haemoglobin concentration than is usual for
that individual
the three classifications of anaemia
Microcytic hypochromic(Small-sized red blood cells (microcytic) with reduced hemoglobin content, making them appear pale (hypochromic).)
Normocytic normochromic(Normal-sized red blood cells (normocytic) with normal hemoglobin content (normochromic).)
Macrocytic(Larger-than-normal red blood cells (macrocytic), which may or may not have normal hemoglobin content.)
note that different types of anaemia fall under different classifications
some clinical features or symptoms of anaemia
shortness of breath
lethargy
retinal harmorrhages
confusion
tachycardia
causes of IDA(iron deficiency anaemia)
depletion of iron levels due to;
Reduced absorption due to dietry deficiency or malabsorption
Blood loss
increased demand for growth in pregnancy
can the size of the RBCs decrease in case of IDA
yes it can, this is known as microcytosis, and is common in IDA
this is due to the lack of haemoglobin
what is meant by the term Hypochromic in IDA
this is used to describe when the RBCs become PALE due to the scarcity of haemoglobin
remember haemoglobin gives the cells their red colour
state three treatments for the treatment of IDA
oral iron supplements (Like ferrous fumerate…)
dietary changes(incroporating iron rich foods into one’s diet)
intravenous iron therapy for extreme cases of IDA, and patients that need more iron than supplements or diet can provide, at a quicker rate
which nutrient helps with the absorption of iron and how does it do it
vitamin c
it does this by reducing ferric iron to ferrous iron or preventing the conversion of iron to ferric iron
methods of diagnosing IDA
POCT( point of care testing)
Laboratory based tests
point of care testing is used for the initial doagnosis, where a quick assessmment of the blood might be required, but for a more accurate diagnosis, laboratory tests are used
some examples of POCT
Hemoglobin testing
hematocrit
POC ferritin or transferrin saturation tests.
Hematocrit (Hct) is a blood test that measures the percentage of your blood volume that is made up of red blood cells (RBCs)
Transferrin is a glycoprotein produced in the liver that binds to iron(III) to help transfer it throughout the body.
examples of lab based diagnosis for IDA
comprehensive diagnosis
peripheral blood smear
Serum Soluble Transferrin Receptor (sTfR)
Reticulocyte Hemoglobin Content
note that the comprehensive diagnosis entails a combination of tests to identify IDA
ferritin
a protein that stores iron in the body and releases it when needed
it is used as an indicator of the body’s iron reserves
what is normally used to collect venous blood from the antecubital vein
a vacutainer
venepuncture
a medical procedure used to access a vein, typically for drawing blood or administering medications
define serum and plasma in terms of blood
serum is the liquid part of the blood after clotting has occurred and the blood cells have been removed.
plasma is the liquid component of anticoagulated blood(blood that has not clotted)
Both serum and plasma are different parts oft he blood, crucial for diagnosing different aspects of Iron Deficiency Anemia (IDA), with serum mainly for iron studies and plasma for blood cell analysis.
does serum have coagulation factors
no, because the blood has already undergone clotting, so they have been used up
does plasma have coagulation factors
yes, because it is composed of anticoagulated blood, so the coafulation factors have not been used up yet.
are there any blood cells left in the serum
No, there are no red blood cells left in serum. When blood clots, the red blood cells, white blood cells, and platelets become trapped in the clot, leaving behind only the serum. Serum is the clear, yellowish liquid that remains after the clotting process and contains electrolytes, proteins (like antibodies), hormones……
note that plasma has all the blood cells
the commonly used anticoagulant for blood cell counting and other associated tests
EDTA
what are the key contents of the blood that are analysed in the full blood count
haemoglobin level
RBC count
WBC count
Platelet count
Red cell parameters
Red blood cell (RBC) parameters are a set of measurements that evaluate the size, shape, and quality of red blood cells
tests that might require the collection of serum
Serum Ferritin
Serum Iron
Transferrin Saturation
Total Iron-Binding Capacity (TIBC)
tests that require the collection of plasma
Complete Blood Count (CBC)
Reticulocyte Hemoglobin Content
Peripheral Blood Smear
Hematocrit
the first line test in haematology
full blood count
name the main types of lymphocytes
B and T lymphocytes
white blood cells are classified into two broad groups, named?
phagocytes and immunocytes
Phagocytes are the granulocytes and monocytes.
Immunocytes are the lymphocytes and plasma
cells.
monocytes enter most tissues and mature into?
macrophages
note that monocytes may specialise into different cells in different tissues
bone marrow samples are usually taken for what purpose
to examine cellular morphology
usually for lymphoproliferative disorders and haematological disease
how are bone marrow samples collected( the two main stages )
bone marrow aspiration: involves the insertion of a needle into the bone marrow to withdraw a portion of it’s liquid part
bone marrow biopsy : involves the use of a larger needle to remove a small core of solid bone marrow tissue
both procedures are usually carried out under local anaesthesia, and biospsy follows aspiration
cell mobilisation and migration
chemotaxis
the movement of cells or organisms in response to a chemical stimulus.
usually happens during infection or injury, with the WBC moving towards the site of injury or infection
the main functions of neutrophils
chemotaxis
phagocytosis
cytokine production…etc
main functions of monoctyes
chemotaxis
phagocytosis
antigen presentation (macrophages)
cytokine production
note these steps are more advanced than
previously learnt
the five main steps involved in phagocytosis and bacterial destruction
Engulfment: A pathogen is engulfed by a phagocyte (like a neutrophil or macrophage), forming a phagosome.
Respiratory Burst: The phagocyte undergoes a respiratory burst, producing hydrogen peroxide (H₂O₂) and other reactive oxygen species (ROS) inside the phagosome to help destroy the pathogen.
Primary Granules (Azurophilic Granules): These granules fuse with the phagosome and release enzymes like myeloperoxidase (MPO), which uses hydrogen peroxide to produce hypochlorous acid (a potent bactericidal agent).
Secondary Granules (Specific Granules): These granules release additional antimicrobial substances like lactoferrin and lysozyme, which attack the pathogen’s cell wall and restrict its iron supply, further aiding in its destruction.
Pathogen Destruction: The combination of ROS from hydrogen peroxide and enzymes from primary and secondary granules leads to the breakdown and death of the pathogen.
function of myeloperoxidase
an enzyme that reacts with hydrogen peroxide to produce hypochlorous acid (HOCl), a powerful antimicrobial agent
function of hydrogen peroxide in bacterial destruction
is key in generating reactive oxygen species that help phagocytes destroy pathogens during phagocytosis
neutropenia
a condition characterized by an abnormally low number of neutrophils
Most commonly associated with infections of
mouth and throat.
causes of neutropenia
Can be caused by drugs
infections
autoimmune disease.
bone marrow disorders
Chemotherapy or radiation therapy, which suppresses bone marrow.
septicaemia
a serious, life-threatening bloodstream infection that occurs when bacteria or their toxins enter the bloodstream, leading to widespread inflammation and potential organ failure.
lymphocytosis
a condition characterized by an abnormally high number of lymphocytes, a type of white blood cell, in the blood
symptoms of lymphocytosis
fever, sore throat,
lymphadenopathy and atypical lymphocytes in
blood film
Lymphadenopathy is a term that refers to the swelling of lymph nodes
causes of lymphocytosis
infection like HIV, Epstein-Barr virus
autoimmune disorders
blood cancers
Infectious Mononucleosis(IM) caused by
Epstein-Barr virus
IM aka glandular fever, and occurs in people aged 15-25
some symptoms of IM
sore throat, lymphadenopathy and
fever, swollen lymph nodes, swollen spleen, headache…etc
mode of transmission of IM
Spread through saliva, which is why it is sometimes referred to as the “kissing disease.”
It can also spread through sharing drinks, utensils, or contact with other bodily fluids.
haemostasis
the process by which the body stops bleeding and maintains blood within the damaged blood vessel following an injury.
it is the balance between procoagulant systems and anticoagulant systems
components of the process of haemostasis
Platelets.
Coagulation factors.
Coagulation inhibitors.
Fibrinolysis.
Blood vessels.
where are platelets produced and how are they produced
produced in the bone marrow by
fragmentation of the cytoplasm of
megakaryocytes
megakaryocytes
large precursor cells that produce platelets
found in the bone marrow. each one produces about 4000 platelets
megakaryocytes mature by
endomitotic
synchronous nuclear replication.
dna replication that does not involve nuclear or cytoplasmic division
endomitotic
synchronous nuclear replication.
a process in which DNA replication occurs without nuclear or cytoplasmic division, and is involved in the maturation of megakaryocytes, which produce platelets.
thrombopoietin
hormone primarily produced by the liver and kidneys, stimulates the development of megakaryocytes and promotes platelet production.
factor IX and X are axctivated by
factor VII
thrombin is produced by factor X
vitamin K function in coagulation
essential for the activation of specific clotting factors in the blood
these coagulation factors are
II: Prothrombin
VII: A coagulation protein
IX: A coagulation protein
X: A coagulation protein
coagulation factor II aka
prothrombin
thrombocytopenia
condition characterized by an abnormally low number of platelets (thrombocytes) in the blood. causes are autoimmune
can cause skin purpura and prolonged bleeding.
can be caused by decreased platelet production, increased platelet destruction, etc
skin purpura
refers to the appearance of purple or red spots on the skin caused by bleeding underneath the skin, due to the rupture of small blood vessels
the most common heriditary coagulation disorder or blood clotting disorder
haemophilia A
a rare, hereditary bleeding disorder that occurs when the body doesn’t produce enough factor VIII, a blood clotting protein
what are some clinical features of haemophilia
Can be discovered from excessive bleeding in infants post circumcision.
Bruising in joints once start to be active.
Can lead to joint deformity
abnormal and excessive bleeding elsewhere in body
haemophilia A
A genetic disorder where the body lacks certain clotting factors (usually Factor VIII) leading to difficulty forming clots. This results in prolonged bleeding, even with normal platelet levels.
sometimes factor IX absence can also lead to haemophilia(B)
the clinical severity of hameophilia is dependant on
the extent of factor VIII deficiency
haemophilia treatment
Gene Therapy:
desmopressin
Antifibrinolytic Medications( like tranexamic acid or aminocaproic acid)
Replacement Therapy: Factor VIII infused for haemophilia A and IX for haemophilia B
