University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

112

Pages:

3
Author:

Mariam A. A.

White Blood cells • Total count is 7 +/- 3 x 10^9/L • Platelets - - - Function: Coagulation (helps with stopping bleeding) Produced in marrow from Megakaryocytes under control of thrombopoietin Bud off Megakaryocytes and enter circulation Life span of 7 to 10 days Structure: ✓ Surface membrane: involved primarily with adhesion ✓ Cytoskeleton: involved with contraction ✓ Granules: alpha granules and dense granules -> involved with secretion of proteins and chemicals that act in haemostasis ✓ Open canalicular system -> important role in clotting of blood i.e., haemostasis Surface glycoproteins: ✓ Important in adhesion, aggregation and therefore formation of platelet plug to stop bleeding ✓ Adhere to sites of vascular injury and to each other and are critical in the formation of a haemostatic plug ✓ Glycoproteins of importance in the haemostatic process include Ib-V-IX (deficient in Bernard –Soulier Syndrome) reacts with von Willebrands Factor (vWF), as does (the IntegrinGP IIb-IIIa) ✓ GP IIb-IIIa (deficient in Glanzmann’ s Thrombasthenia) which is also a fibrinogen receptor Dense granule contents ✓ Dense Granules- electron dense granules which contain nucleotides (ADP), Ca2+ and seratonin. ✓ Alpha-granules – contain predominantly proteins such as platelet factor 4, Platelet-derived growth factor, fibrinogen, vWF, P-selectin ✓ During platelet activation the platelet releases the granule contents via an open canalicular system ✓ Mitochondria and glycogen - • Basophils - - • Function: are associated with allergic reactions. They contain cytoplasmic granules, which contain heparin, histamine and substances that promote inflammation. Count: 0.02-0.1 x109 /L or Histological appearance: ✓ S shaped or 2 lobes ✓ Diameter 14-16 micrometre ✓ Has large granules Eosinophils - - • Histological appearance: ✓ No nuclei ✓ Very small (2-4 micrometres in diameter) ✓ Basophilic/purple appearance Function: Eliminates worms and parasites that are too large for phagocytosis. This is done because they have granules that contain toxic chemicals in granules when they bind to them (degranulation) Count: 0.02 to 0.5 x109 /L , 1-6% of white cells Interleukin-5 influences development in marrow Histological appearance: ✓ Large and pink ✓ Diameter 12-17 micrometre ✓ Nuclei has two lobes Neutrophils - - Function: Engulf bacteria by phagocyte count is 2-7 x109 /L (40-80% of white cells) duration: 6 hours exhibit chemotaxis (complement and kinin generated), phagocytosis, degranulation and inflammation in adjacent tissue NADPH deficiency -> in ability to produce types of reactive oxygen species -> inability to kill bacteria (Chronic Granulomatous Disease) - • Lymphocytes - • 1.0-3.0 x10^9/L or 20-40% of peripheral blood white cell count Different types: T, B and NK cells T-lymphocytes - • Histological appearance: ✓ Nuclei have 2-5 lobes ✓ Number of lobes decreases with age ✓ 12-14 micrometre Function: Directly destroy their target cells by releasing chemicals that punch holes in the victim cell T Lymphocytes predominate in blood (75%-85%) and develop in thymus Involved in cell mediated immunity Histological appearance: ✓ Large nucleus B-lymphocytes - Function: antibody Production Involved in humeral immunity Typical surface proteins of B-cells are CD19 and CD20 Histological appearance: ✓ Large nucleus