Lecture 4 Flashcards
What is haematology?
The study of blood, particularly focused on disorders of the blood and involves the haematopoietic system.
What components make up blood?
Cells (white blood cells, red blood cells, platelets) and plasma (water, electrolytes, gases, proteins, etc.).
What are the primary functions of blood?
Transporting oxygen, nutrients, hormones, and waste products; regulation of body temperature and pH; immune defense.
What are the normal adult concentrations of erythrocytes?
4-6 x 10^12 cells/L (40-50% by volume).
What are the normal adult concentrations of leukocytes?
4-11 x 10^9 cells/L.
What are the normal adult concentrations of thrombocytes?
1-4 x 10^11 cells/L.
What are the two main blood cell lineages?
Lymphoid and myeloid.
What are erythrocytes also known as?
Red blood cells (RBCs).
What gives RBCs their flexibility?
A mesh structure of spectrin and actin.
What are common signs of anaemia due to low RBC count?
Pallor, breathlessness, fatigue due to reduced oxygen transport.
What is polycythaemia?
A condition with too many RBCs, leading to increased blood viscosity.
Where are white blood cells produced?
Primary lymphoid tissues such as bone marrow and thymus.
Where do white blood cells function?
Secondary lymphoid tissues such as the spleen, lymph nodes, and mucosa-associated lymphoid tissue (MALT).
What unique features help identify WBCs?
Morphologies, nuclear shapes, granules, and surface markers.
What is a common method to analyze cell surface markers?
Flow cytometry or immunohistochemistry.
What does haematoxylin stain in cells?
Nucleic acids, turning them blue-purple.
What does eosin stain in cells?
Proteins, turning the cytoplasm pink.
What are non-specific esterases used for?
Histochemical staining, converting α-naphthyl acetate to a colored product.
What is the primary use of immunohistochemistry in haematology?
Identifying antigens on cell surfaces using antibodies linked to chromophores or enzymes.
What does flow cytometry do?
Counts cells and measures fluorescence intensity, shown in dot plots.
Name one exclusion marker and the cell it identifies.
CD3 for T cells.
What are common markers for B cells?
CD38+ and CD138+.
What is thrombocytopenia?
A condition characterized by a low platelet count.
What are the main components of plasma proteins?
Albumin, α globulins, β globulins, γ globulins.
Which organ synthesizes most plasma proteins?
The liver, except for γ-globulins (immunoglobulins).
What is the difference between plasma and serum?
Serum is plasma without clotting factors, remaining after blood has clotted.
What is albumin’s role in blood?
Carries substances with low solubility, binds calcium, and helps maintain blood osmolarity.
What is the role of α-globulins?
Transport of lipids, hormone binding, and enzymatic activity.
What is the role of γ-globulins?
They are antibodies involved in immune response.
What triggers the clotting cascade?
Damage to the endothelium, activating a series of coagulation factors.
What is haemostasis?
The process of maintaining fluid blood within the circulatory system, involving vasoconstriction, platelet activation, and coagulation.
How do platelets adhere during haemostasis?
Through integrins like α2β1 binding to collagen and α2bβ3 binding to fibronectin or vitronectin.
What is von Willebrand factor’s role?
Binds to platelets and collagen, fixing them to the injury site.
What substance do activated platelets release to promote aggregation?
ADP and thromboxane A2 (TXA2).
What are mechanisms to prevent excessive clotting?
Thrombomodulin-thrombin complex activating protein C, antithrombin inactivating thrombin, ADAMTS13 degrading vWF.
What enzyme degrades fibrin to remove clots?
Plasmin, activated from plasminogen.
What activates plasminogen?
Tissue plasminogen activator (tPA).
What are the functions of plasma proteins?
Transport, blood pressure regulation, immune response, and clotting.
What are polypeptide hormones found in plasma?
Hormones such as insulin and growth factors.
What is opsonisation?
The marking of pathogens for phagocytosis, facilitated by complement proteins.
What is chemotaxis?
The movement of immune cells towards sites of infection or injury, driven by chemical signals.
Name a plasma protein involved in clotting.
Fibrinogen.
What role does haptoglobulin play?
Binds free hemoglobin to prevent oxidative damage.
What is α1-antitrypsin?
A protein that inhibits the enzyme trypsin and protects tissues from enzyme damage.
Why is TXA2 significant in haemostasis?
It activates platelets and acts as a vasoconstrictor to reduce blood flow.
What is the purpose of anticoagulants like antithrombin?
They prevent excessive clot formation by inactivating thrombin.
What is the importance of ADAMTS13?
It regulates clotting by breaking down von Willebrand factor (vWF).
Why is the clotting process balanced?
To prevent excessive bleeding or thrombosis, ensuring controlled clot formation and removal.
What is a common treatment for anaemia?
Recombinant human erythropoietin (rHuEPO).
What are case scenarios where EPO is used?
CKD, cancer-related anaemia, preoperative surgery, and HIV-related anaemia.
What is the result of successful EPO therapy?
Increased hemoglobin levels and improved patient quality of life.
