Hematology

1. Board Review - Hematology
Dr. E. E. Okon MRCS

2. Hematology

Anatomy
 Embryology & Histology

Physiology

Pathology

Pharmacology

3. Anatomy

Physiology and pathology of blood and blood-
forming organs.

Precursor - Pluripotent hematopoietic stem cell
(HSC).

(hemo: blood; poiesis:creation) stem cells
 self-renewal and differentiation
 generate, maintain, and repair tissues
 survive 2–4 weeks

4. Anatomy

Blood
 Specialized connective tissue

Components?
 Blood cells
 Plasma
 Serum


6. Anatomy

Myeloid Lineage
 Erythrocytes (RBCs): Shape,
 Sites of production: Yolk sac,Placenta, Liver,
Spleen, Bone marrow
 They lose most of their cell contents. Why?

Life span is about 120 days.

Reticulocytes: Immature RBC with reticular
network of rRNA.

7. Myeloid Lineage

Leukocytes
 Highest percentage to lowest: Neutrophils,
Lymphocytes, Monocytes, Eosinophils, Basophils
 Neutrophils: Polymorphonuclear neutrophils
(PMNs); 50% to 80%

first responders in the acute phase of inflammation

Nonsegmented (band) neutrophils

Segmented – 3 to 5 nuclear lobes

Hypersegmented?


9. 
Monocytes
 Kidney-shaped nucleus
 2% to 10%
 Act to clean up circulating debris, microorganisms,
senescent RBCs, and damaged cells.
 Monocytes in blood; macrophages in tissues

Kupffer cells

Alveolar Macrophages

Oligodendrocytes

Glial Cells


Macrophages – Function as APCs – Antigen
Presenting cells via MHC II.

10. Anatomy

Hematopoietic stem cells (HSCs)
 common myeloid progenitor (CMP) cell
 common lymphoid progenitor (CLP) cell

Myeloid Progenitor cell types

Lymphoid progenitor cell types

11. 
Eosinophils
 Bilobed nuclei and have prominent eosinophilic
(reddish-orange) granules
 1% to 6%
 Major Basic Protein (MBP)
 Mnemonic for the causes of Eosinophilia (NAACP)
 Neoplasia Asthma Allergies Collagen vascular
disease Parasites

13. 
Basophils
 Bilobed nuclei but have granules
 Inflammatory reactions that cause allergic
symptoms.
 Express Immunoglobulin E (IgE) receptors
 Release chemokines
 Mast cells in tissues

Platelets/Thrombocytes
 Originate from megakaryotes
 Anucleate
 Lifespan – 7 to 10 days (First 2 days spent in the
spleen)
 150,000 – 400,000/mm³

15. Lymphoid Lineage

Lymphocytes are also leukocytes

Originate from CLP cells

25% to 33%

T cells

B cells

Plasma cells

Natural killer (NK) cells.

17. 
T-Lymphocytes
 mediate the cellular immune response
 Made in the bone marrow
 Mature in the thymus
 Reside in lymphoid tissues
 CD 4 & CD 8 T-cells

18. 
CD 4 T-cells
 Helper cells
 Bind to MHC II – MHC II is present on the surface
of APCs

CD 8 T-cells
 Eliminate T cells, viral cells, virus-infected cells
 Bind to MHC I – MHC I is expressed by all cells in
the body except platelets & RBCs

NK cells – tumor cells & viral-infected cells
 perforin and granzyme

B-lymphocytes
 Humoral immune system
 Create Antibodies

19. Hematology

Anatomy
 Embryology & Histology

Physiology

Pathology

Pharmacology

20. Hematology

Physiology

Blood groups A, B, AB, O

Blood Groups: ABO and Rh Systems
 Presence of surface antigen(s) on RBCs.
 Presence of plasma antibodies (Ab) against
antigen(s) not present on RBCs
 Presence or absence of Rh factor


21. 
Rh system
 D, C, c, E, e on the RBC
 D antigen – most immunogenic
 Rh-negative people do not produce the D antigen
 Do not produce anti-Rh Abs.
 Rh-negative individuals can become sensitized

Blood transfusion

Pregnancy: Rh immunoglobulin (RhoGAM)
 RhoGAM at 28 weeks of pregnancy
 within 72 hours after delivery


22. USMLE Step 1 question

A 28year old woman gravida 2, para 1, at 27
weeks gestation presents to the clinic for
antenatal. She denies any complaints except
for back pain. Blood investigations reveal she is
blood group B negative. The father of the fetus
is A positive. Which of the following precautions
must be ensured?

23. Hemostasis