Platelets & WBCs Flashcards
about Blood Platelets (Thrombocytes)
1. Number:………..
2. Increase in number………………
3. Decrease in number………….
4.Life span…………
5. Senescent platelets are phagocytosed by ………. primarily in the ………..
- 150.000- 400.000/mm³
- Thrombocytosis
- Thrombocytopenia
- 10 days
- macrophages/ spleen
illustrate Origin of Blood Platelets (Thrombocytes)
The platelets are cell fragments derived
from the megakaryocytes in the bone
marrow
illustrate Morphology (structure) of platelet by L.M
- Size: 2 - 4 µm in diameter.
- Shape: oval disk shaped (cell fragments).
- Nucleus: They lack nuclei
- they display a peripheral clear region called hyalomere and denser granular center called the granulomere
illustrate Morphology (structure) of platelet by E.M.
- The cell membrane coated by glycocalyx (glycoproteins and glycolipids) to be involved in platelets adhesion
- Cytoplasm: divided into 2 regions:
1. Hyalomere:Peripheral clear region
2.Granulomere:Central granular region
illustrate Hyalomere
- It is the peripheral part. It shows:
a) Marginal bundle consisting of:
- 10 -15 microtubules arranged parallel to each other forming a ring within the hyalomere. They assist in maintaining the discoid form of the platelets.
- Actin and myosin microfilaments helping contraction of the platelets during retraction of blood clot.
b) Two tubular systems:
- Open canalicular system: which is invagination from the cell membrane, facilitating platelets’ uptake of factors from plasma. Also, this system facilitates rapid degranulation upon activation and Ca release.
- Dense tubular system: which may be remnants of endoplasmic reticulum of megakaryocytes (stores Ca ions)
illustrate Granulomere composition
- Mitochondria
- Glycogen
- (3) types of granules :
Delta, Alpha, lambda
- Alpha granules (majorty):
Fibrinogen
PDGF
coagulation factors.
Platelet factor 4.
- Delta granules:
ADP
ATP
Ca
Serotonin
- Lambda granules:
Lysosomes
illustrate Development of platelets
(thrombopoiesis)
- Platelets are continuously produced in red bone marrow.
1- Stem cells:
- Pluripotent hemopoietic stem cell (PHSCs)
- multipotential myeloid stem cell
2- Progenitor cells:
- colony forming unit megakaryocyte (CFUMeg)
- Megakaryoblast (Immature
megakaryocyte):
- Size: large cell 25-50μm.
- Nucleus: large with numerous nucleoli.
- Cytoplasm: highly basophilic homogenous non-granular.
- Before differentiation, they undergo endomitosis, with repeated rounds of
DNA replication not separated by cell divisions, resulting in a nucleus that is
highly polyploid
4.Megakaryocyte (mature cell) :
- Size: a giant cell up to 150 μm
- Nucleus: large lobulated and polyploid.
-Cytoplasm: basophilic - granular.
-It contains numerous mitochondria,well
developed rER, extensive Golgi complex, α granules, lysosomes (lambda granules) and dense bodies.Megakaryocytes are located near sinusoids, extend their long
processes through fenestrae of endothelial cells into the sinusoidal lumen. Platelets are separated from the top of these processes and washed out with circulation.Invagination from cell membrane forming the demarcation membranes that represent reservoirs for rapid elongation of the processes.
about Megakaryocyte
1. Is a ………….cell
2. Nucleus is large ….. stained.
3. Cytoplasm is …………
- giant
- lobulated & deeply
- basophilic.
list def & classification of Leucopoiesis
- it is the development and maturation of WBCs.
- It is classified into two main categories of Development of :
1- granulocytes.
2- agranulocytes
illustrate GRANULOPOIESIS
- PHSCs→ multipotent myeloid stem cells→ colony forming unit- granulocytes-monocytes (CFU-GM) → Myeloblasts.
- Myeloblasts:
*large and rounded cells with basophilic, non-granular cytoplasm.
*Large, rounded nucleus with one or more nucleoli. - Promyelocytes:
*Larger in diameter with large nuclei.
*Basophilic cytoplasm that contains non-specific azurophilic granules - Myelocytes:
* Smaller in size.
* The nucleus has a deep indentation and assumes an eccentric position within the cell.
* The cytoplasm is basophilic, contains both types of granules; specific and non-specific. So, there will be three types of myelocytes:
❖ Neutrophilic myelocytes: with specific neutrophilic granules.
❖ Eosinophilic myelocytes: with specific acidophilic granules.
❖ Basophilic myelocytes: with specific basophilic granules.
At this stage, myelocytes lose their capacity for mitosis and they change to metamyelocytes (stop mitosis). - Metamyelocytes:
* Smaller cells with more specific granules
* and less developed organelles.
* Nucleus becomes kidney-shaped with more condensed chromatin.
* Neutrophilic metamyelocytes pass through an intermediate stage where the nucleus becomes curved rod (band cells), then, they pass to mature neutrophils with segmented nucleus. - Mature granular leucocytes.
illustrate Lymphopoiesis
- PHSCs→CFU-Ly→CFU-T lymphocytes→ T lymphoblast
(large cells), that migrate to the thymus cortex → Prolymphocytes (smaller, acquiring their specific cell surface
markers according to the environment) → T-lymphocytes. - PHSCs→CFU-Ly→CFU-B lymphocytes→ B lymphoblast (large cells) → Prolymphocytes (smaller, acquiring their specific cell surface markers according to the environment) → B- lymphocytes and NK cells in bone marrow.
- Mature B and T lymphocytes leave the bone marrow and thymus respectively and circulate to reach peripheral organs as lymph node and spleen
illustrate Monocyte Development
- Occurs in red bone marrow
- Stem cells:
- PHSCs
- multipotential myeloid stem cells - Progenitor cells:
- colony forming unit- GM
- CFU-monocytes - Precursor cells:
- Monoblast
- Nucleus: Large pale staining with prominent nucleolus.
- Cytoplasm: Basophilic
- Pro-monocyte
- Nucleus: large intended with numerous nucleoli.
- Cytoplasm: basophilic. - Mature cells:
- Monocyte
- Mature monocytes circulate for only 8 hours
- They enter CT and differentiate into macrophages which function for several months.
about Leucocytes (White blood cells)
1. Are true……….., having nuclei and organelles.
2. Are ………….. than RBCs.
3. Have ………… life span.
4. Normally, total leucocytic count is about………….
- spherical cells
- larger and much less numerous
- shorter / (most last hours to days).
- 4.000-11.000/mm³.
- Classify leucocytes
- Granular :
- Neutrophils
- Eosinophils
- Basophils - Non-granular :
-Lymphocytes
- Monocytes
about Neutrophils (Polymorphonuclear
leukocytes)
- Number………….. of total leucocytic count.
- by L.M. - Size : ………….
- Shape: …………..
- Nucleus: …………….
- Cytoplasm: ……………..
- Life span: ……….in blood and ………… in connective tissue before dying by ………………
- Some mature neutrophils of human female show ……….. as a drum stick appendage (Barr body), which is the inactive X-chromosome.
- while the immature cells (band neutrophils) contain ………………… nucleus. Band neutrophils are not more than ……….in blood film under normal condition
- 60-75%
- 12-15 µm
- Rounded
- condensed and segmented
(multilobed, formed of 3- 5 lobes
connected by thin strands of chromatin). - is heavily populated with fine neutrophilic granules.
- 6-8 hours / 1-4 days / apoptosis.
- sex chromosome
- one bent rod (or horse-shoe) / 1-2%
about Neutrophils (Polymorphonuclear
leukocytes) By E.M.
- Few organelles………….
- Membrane-bounded granules
I…………….
II…………….
- (mitochondria, small Golgi complex and rER)
2.
I. 1- Neutrophilic granules 80%
II. - Azurophilic granules (20%):
lysosomes
list chc of Neutrophilic granules
-small & numerous
- Alkaline phosphatase
- Bacteriostatic enz (lactoferrin).
- Collagenase
list chc of Azurophilic granules
- Large& few
- Hydrolytic enzymes
- Proteolytic and lipolytic
list function of Neutrophils (Polymorphonuclear leukocytes)
- body defense (in pyogenic infection):
Neutrophils are the first line of defense against bacterial invasion - Apoptotic neutrophils, bacteria, semi-digested material, and tissue fluid form a viscous, usually yellow collection of fluid called pus
about Eosinophils
1. Number ….. of total leucocytic count.
2. Life span……… in blood and …….. in connective tissue.
3. Increased number ………………
(in ……………..)
- 1-5%
- Few hours / 1-2 weeks
- Eosinophilia / allergy & parasitic infestation
about eosinophil by L.M.
1. Size & shape: ……….
2. Nucleus: …………..
3. Cytoplasm: ………….
- rounded cells, 12-15 µm in diameter.
- bilobed or horse-shoe
- small Golgi apparatus, few mitochondria, rER, moderate
amount of glycogen. packed with numerous large, refractile and acidophilic granules
illustrate Membrane-bounded granules in eosinophil
- Specific granules :
- large ovoid
- Crystalline electron dense core = internum surrounded by less dense zone called the externum. - Azurophilic granules:
- Lysosomes
illustrate content of Membrane bounded specific granules
1- major basic proteins (MBP) and eosinophilic peroxidase (both
have anti-parasitic worms & helminths).
2- contain histaminases and arylsulphatase (anti-allergic) which
degrade histamine and slow reacting substance of anaphylaxis (SRSA) released by mast cells and basophils during hypersensitivity reaction
what about Azurophilic granules ?
smaller and less in number.
They are lysosomes containing hydrolytic enzymes (anti-parasitic and also hydrolyze the Ag-Ab complex)
about Basophils
1. Number………… of total leucocytic count.
2. Life span………. in blood and …………… in connective tissue.
3. Increased number ………….in………
- 0.5-1%
- Few hours / several months
- basophilia / allergic reactions
describe basophil by L.M. & E.M.
L.M.:
1. Size & shape: rounded cells, 10-12 µm in diameter.
2. Nucleus: is irregular (or S-shape).
3. Cytoplasm: is packed with large basophilic granules masking the nucleus
(metachromatically stained by Toluidine blue)
E.M.:
1. Few organelles.
2. Membrane-bounded granules
- Specific gr. :
Large electron dense.
Contain heparin, histamine, ECF & NCF.
- Azurophilic granules :
Few lysosomes
illustrate the function of basophil
Function:
1. Release of specific granules content promotes allergic reaction similar to mast cells.
2. Histamine causes vasodilatation and smooth muscle contraction
about Lymphocytes
1. Constitute ……..
of total leucocytic count.
2. Life span…………… vary according to their specific functions; some live only a…….. and others survive in the circulating blood or other tissues for
- 20-25 %
- few hours / many years
- Lymphocytes are classified according to ……………
- into :
- …………..
-…………….
-……………..
- their size
2.
- Small Lymphocytes
- Medium sized lymphocytes
- Large sized lymphocytes
about Large lymphocytes:
1. ……….. in diameter.
2. They are present mainly in …..
3. The majority of large lymphocytes seen in blood represent ………
4. Some circulating large lymphocytes are …………
- 15-18 μm
- lymphatic tissue.
- activated B lymphocytes
- natural killer (NK) cells
Both medium & large lymphocytes are …………..
activated lymphocytes
classification of lymphocytes according to function :
1. …………
2. ………….
- T Lymphocytes
Mature in Thymus - B Lymphocytes
Mature in BM
describe shape of lymphocytes
Shape: Both B & T lymphocytes are similar in appearance. The small cells are spherical with large central, rounded and condensed nucleus
describe Nucleus of lymphocytes
Small lymphocytes have spherical nuclei occupying most
of the cell while the Larger lymphocytes have larger, slightly
indented nuclei.
describe shape of lymphocytes By E.M
- Few organells but many free ribosomes.
- Few azurophilic granules (lysosomes).
- Surface is covered by microvilli.
describe Cytoplasm of lymphocytes
Small lymphocyte show thin rim of basophilic cytoplasm surrounding the nucleus, while larger lymphocytes
show more slightly basophilic cytoplasm
describe Cytoplasm of lymphocytes
Small lymphocyte show thin rim of basophilic cytoplasm surrounding the nucleus, while larger lymphocytes
show more slightly basophilic cytoplasm
about small lymphocytes
1. percentage……..
2.size ……
3. nucleus………
4. cytoplasm……..
5. EM………
- 92% of circulating lymphocytes
- 6 – 9 μm
- Rounded indented
- Thin rim of basophilic cytoplasm
surrounding the nucleus - Many Free ribosomes Few Mitochondria, Golgi complex and rER
about medium lymphocytes
1. percentage……..
2.size ……
3. nucleus………
4. cytoplasm……..
5. EM………
- 8%
- 10 – 15 μm
- Larger indented, lightly stained
- More cytoplasm, slightly basophilic
- Large number of mitochondria, abundant rER, few polysomes, well-developed Golgi complex.
- To differentiate between B and T lymphocytes, ………..are used to specific surface markers
labeled antibodies
about Monocytes
1. Number ….. of total leucocytic count.
2. Size & shape ……….
3. Nucleus………..
4. Cytoplasm……….
5. Organelles………..
6. Life span ………….
- 3-8 %
- rounded large cells, 12-20 µm.
- large, kidney-shaped
- basophilic, many azurophilic granules
(lysosomes). - mitochondria, prominent Golgi complex, few rER, sER and ribosomes.
- From few hours to many years
illustrate the function of monocytes
- They migrate to the connective tissue to differentiate into macrophages.
- Circulating monocytes are highly phagocytic cells. They phagocytose bacteria, virus and foreign bodies
1…………………., extravasation of monocytes occurs, and they change into macrophages that migrate to the connective tissue at the site of injury.
- …………………….., continuous recruitment of monocytes occurs leading to continuous presence of macrophages causing excessive tissue damage.
- In acute inflammation
- In chronic inflammation
