BI1BP2 - Pathology

• What is the primary function of red blood cells (RBCs)?

  To supply oxygen to tissues and cells and help remove carbon dioxide
• Which part of blood helps fight infection?

  White blood cells
• What role do platelets play in the blood?

  They prevent vascular leaking and are involved in coagulation
• What are the key components of RBC histology?

  • Blood smear stained with Romanowsky stain
  • Methylene blue stains nuclei purple
  • No nucleus
  • Eosin stains cytoplasmic proteins pink
  • Full of haemoglobin
  • No mitochondria
  • Biconcave discs, 7-12µm, ~90fL
• What is the pathophysiology of RBCs in anaemia?

  It is the inability to transport sufficient O2/CO2 around the body
• What is the definition of anaemia?

  Reduced haemoglobin concentration in the blood
• What percentage of women and men are affected by anaemia?

  10% of women and 2-5% of men
• What are common causes of anaemia?

  Acute bleeding, chronic bleeding, iron deficiency, folate/Vitamin B12 deficiency, and premature destruction of RBCs
• What are some signs and symptoms of anaemia?

  Shortness of breath, tachycardia, pallor, and fatigue
• How is anaemia diagnosed?

  • Acute bleeding: low RBC count, normal size/colour
  • Chronic bleeding: depends on resulting deficiency
  • Iron deficiency: normal count, small pale RBCs
  • Folate/B12 deficiency: normal/low count, large RBCs
  • Haemolysis: low count, normal size/colour
  • FBC: Hb concentration <120g/L, RBC count, size, and colour
• What is the treatment for anaemia?

  Depends on the cause, may include stopping bleeding, iron-rich foods, supplements, B12 injections, or blood transfusion
• Can a person with a normal RBC count still be anaemic?

  True
• What is leukaemia?

  Uncontrolled growth of one WBC type in the bone marrow
• What are the five types of white blood cells (WBCs)?

  • Lymphocyte
  • Basophil
  • Neutrophil
  • Monocyte
  • Eosinophil
• What is the role of neutrophils in the immune response?

  They migrate out of blood into tissues where needed and are elevated in bacterial infections, stress, and exercise
• What is the function of lymphocytes?

  They sit in lymph nodes to screen lymph and are elevated in viral infections
• What is the role of monocytes in the immune system?

  They clear cell debris and are elevated in infection, inflammation, and tissue damage
• What is the role of eosinophils?

  They are involved in allergies and intestinal parasites
• What is the role of basophils?


  They are involved in allergic reactions
• What happens when the physiology of WBCs goes wrong?

  It can lead to deficiencies such as neutropenia or conditions like leukaemia
• What are the four main classes of leukaemia?

  • Acute myeloid leukaemia (AML)
  • Chronic myeloid leukaemia (CML)
  • Chronic lymphoid leukaemia (CLL)
  • Acute lymphoblastic leukaemia (ALL)
• What are common causes of leukaemia?

  Usually unknown, occasionally chemicals, radiation, viral, or genetic factors
• What are the signs and symptoms of leukaemia?

  Anaemia, leukopenia, and thrombocytopenia
• How is leukaemia diagnosed?

  • FBC: increased affected WBC type, decreased other WBCs, RBCs, and platelets
  • Bone marrow biopsy: increased immature WBCs, possibly enlarged nuclei (immature blast cells)
• What are the treatments for leukaemia?

  Chemotherapy and bone marrow transplant
• What do platelets appear as in blood films?

  • Dark-staining granules
  • Tiny discs (2-4µm) under SEM
  • Change shape with activation
  • Numerous: 150-400 x 10$^9$/L
  • Anucleate fragments of megakaryocytes
• What is the function of platelets in haemostasis?

  They play a role in the cessation of bleeding
• What are the steps in platelet plug formation?

  1. Injury to blood vessel

  2. Collagen exposed

  3. Platelet adhesion

  4. Platelet activation

  5. Platelet secretion

  6. Platelet aggregation

  7. Fibrin strands trap cells forming a stable thrombus or clot
• What is the simplistic coagulation process?

  Fibrin is produced by active thrombin at sites of tissue injury
• What is fibrinolysis?

  It is the process of breaking down fibrin to re-establish blood flow
• What causes arterial thrombosis?

  Inappropriate activation of platelets due to atherosclerosis
• What is Virchow’s Triad related to venous thrombosis?

  It includes stasis, endothelial damage, and hypercoagulability
• Where does Deep Vein Thrombosis (DVT) commonly occur?


  In the deep veins of the legs
• What are the symptoms of arterial thrombosis?

  Pain in the leg, tenderness, swelling, redness, heat, fever, malaise, elevated WBC, and erythrocyte sedimentation rate
• How is arterial thrombosis diagnosed?

  • Diagnosis depends on location
  • Peripheral arterial disease (PAD): Ankle-brachial index, ultrasound, MRI
  • Ischaemic stroke: Clinical assessment from signs/symptoms
• What is the role of plasmin in fibrinolysis?

  Plasmin breaks down fibrin to restore blood flow
• What are the common causes of thrombosis?

  • Inappropriate activation of platelets
  • Atherosclerosis in arteries
  • Virchow’s Triad in veins
• What is the relationship between thrombosis and immobility?

  Immobility can often lead to venous thrombosis, such as DVT
• What is the role of collagen in platelet activation?

  Collagen exposure initiates platelet adhesion and activation
• What is the significance of platelet aggregation in clot formation?

  Platelet aggregation leads to the formation of a stable thrombus or clot