Blood Histology PDF

# BLOOD HISTOLOGY Dr. Ahmed Adel ## The blood cells > Def: the fluid of life, contained in the closed circulatory system. ### Blood - Plasma (Fluid part) - Represent 55% - Cells - Represent 45% - RBCs - WBCs - Platelets ### Red Blood Corpuscles (RBCs) (Erythrocytes) - **Shape**...

# BLOOD HISTOLOGY Dr. Ahmed Adel ## The blood cells > Def: the fluid of life, contained in the closed circulatory system. ### Blood - Plasma (Fluid part) - Represent 55% - Cells - Represent 45% - RBCs - WBCs - Platelets ### Red Blood Corpuscles (RBCs) (Erythrocytes) - **Shape** - Biconcave discs. - In slow blood stream: "Rouleaux". - **Size** - Normal: 6-9 µm (average 7.5 µm). - **Colour:** - Single RBC → greenish yellow due to minimal HB. - In stained sections → red as it contains a large number of RBCs. - acidophilic with a pale center - **Number:** - Males: 5-5.5 million /mm3. - Females: 4.5 - 5 million /mm3 (decreased due to menstruation and female sex hormones) - **Structure & Adaptation to Function:** - Biconcave disc → ↑ surface area for more gas exchange. - Plastic → Squeezed in narrow vessels without rupture. - Selective permeability → Easy exchange of O2 and CO2 but not HB. - Absent Nucleus → More space to HB for gas exchange. - Absent organelles → More space to HB for gas exchange. - Carbonic anhydrase → CO2 transportation from tissues to the lung. ## Abnormalities of RBCs | Abnormal Shape | Abnormal Size | Abnormal Number | Abnormal Color | |--------------------|-----------------------|----------------------|-----------------------| | Spherocytosis | Normal 6-9 um | Oligocythemia→ Anemia | Hypochromic | | | Microcytic Anemia | Polycythemia | Normochromic | | | Macrocytic Anemia | | Hyperchromic | ## White Blood Cells (WBCs) (Leucocytes) - Def: True nucleated cell - Colour: Single WBC is colorless but aggregated WBCs appear white. - Count: (4000-11000/mm3). - Leucopenia <4000 - leukocytosis >11000 - white blood cells ~ WBC ### agranular | Lymphocytes | Monocytes | Basophils | |--------------------|-------------------|-----------| | 20-25% | 3-8% | .5-1% | ### granular | Neutrophils | Eosinophils | |-------------|-------------| | 60-70% | 2-4% | - Total Leucocyte count: It is the total number of leucocytes in 1 mm3 of blood. - Differential leucocyte count: It is the percentage of each type of leucocytes in blood. ## Granular leukocytes | | Neutrophils | Eosinophils | Basophils | |----------------|--------------|--------------|------------------| | Percentage | 60-75% | 2-5% | 0.5-1% | | Size | 10-12 μm | 12-15 μm | 10-12 μm | | LM | | | | | Nucleus | Single, Segmented (2-5 segments) | Bilobed or horse-shoe shaped.| Large, Irregular.| | Cytoplasm | Fine neutrophilic granules. | Large acidophilic refractile granules. | Obscured by cytoplasmic granules. | | | | | Large basophilic granules | | Function | Defense mechanism: As they migrate to the infected area and phagocytose bacteria and foreign bodies resulting in pus formation (so called microphages). | Anti-allergic action through: 1. Phagocytosis of Ag-Ab complex. 2. Histaminase & sulphatase → destroy excess histamine & other substances causing allergy. | Produce histamine & heparin during allergy. | ## Non granular leukocytes | | Monocytes | Lymphocytes | |----------------|--------------|--------------| | Percentage | 3-8% | 25-30% | | Diameter | 15 μm | 6-8 μm (B&T) | 10-12 μm | | LM | | | | | Nucleus | - Large & pale. - Kidney or horse-shoe shaped. | - Dark. - Rounded. | - Pale. - Indented. | | Cytoplasm | - Abundant. - Pale basophilic. | - Little rim around nucleus. - Pale basophilic.| - Abundant. - More basophilic.| | Function | Phagocytic function as they migrate through the wall of capillaries and venules into the surrounding C.T. → macrophages. | - B lymphocytes Humoral immunity. - T lymphocytes Cell mediated immunity.| | ## Platelets (Thrombocytes) - **Structure**: Formed of cytoplasm covered with a membrane with no nucleus (not true cells) - **Counts**: 150000-400000/mm3 - **Shape**: oval or rounded discs - **LM**: - Outer pale blue part (hyalomere) - Central granular part (granulomere) - **origin**: megakaryocyte - **Function**: → Stop bleeding (Hemostasis) 1. Serotonin → V.C. → ↓blood loss) 2. Platelet aggregation (white thrombus): Platelets adhere to the wall of injured blood vessel 3. Red thrombus (coagulation): Platelets secrete Thromboblastin which changes prothrombin into thrombin → change fibrinogen into fibrin network → attraction of RBCs → closes blood vessel and stops bleeding. ### Diagram of Platelet Aggregation - Vessel injury - Endothelial cells (a) - Vascular spasm - Platelet plug formation - Collagen fibers (b) - Platelet plug - Blood clotting - Fibrin (c) ## Quiz **Which of the following formed elements do not contain a nucleus?** a. Basophils b. Erythrocytes c. Leukocytes d. Monocytes e. Lymphocytes **Which of the following is a granulocyte?** a. Thrombocyte b. Lymphocyte c. Eosinophil d. Monocyte e. Erythrocyte **The normal total leucocytic count is:** a. 4000-11000/mm3 b. 2000-7000/mm3 c. 1000-5000/mm3 d. 7000-11000/mm3 e. 5000-12000/mm3 **About monocytes : one is true:** a. Their percentage is from 3-8%. b. Their nucleus is segmented. c. They have a role in allergy. d. The cytoplasm has acidophilic granules. e. They can be transformed into plasma cell. **Regarding RBCs:** a. True nucleated cells b. Drop of blood appears greenish yellow in color c. Biconcave discs d. Total count is 4000-11000/mm3 e. Cytoplasm has numerous organelles. **Which leukocyte is the most abundant in a peripheral smear of blood?** a. Lymphocytes b. Basophils c. Neutrophil d. Monocytes e. Eosinophils