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Histology > Chapter 5: Blood > Flashcards

Chapter 5: Blood Flashcards

1
Q

What is blood?

A

It is a special type of C.T. That circulates inside blood.

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2
Q

What is blood formed of?

A

Cells and an extracellular fluid matrix called plasma.

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3
Q

What is the composition of blood?

A

It is made of 45% blood cells (erythrocytes, leukocytes, and platelets) and 55% plasma.

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4
Q

Examination of the blood using a blood film.

A

A drop of blood is spread on a glass slide and left to dry in air.

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5
Q

Blood examination using staining

A

With a neutral stain (Eg. Leishmans stain) formed of a mixture of red acidic stain Eosin and blue basic stain methylene blue dissolved in methyl alcohol (fixative).

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6
Q

Erythros

A

Red

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7
Q

What are Red blood corpuscles?

A

Non-nucleated biconcave discs.

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8
Q

RBC’s shape

A

Top view: rounded.
Side view: biconcave, to increase surface area for the exchange of gases.

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9
Q

What is the reason behind abnormal shapes of the RBC’s?

A

It is due to changes either in the cell membrane or Hb content. They are more fragile and more prone to hemolysis causing anemia.

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10
Q

What are the types of abnormal shapes?

A
  1. Spherocytes: spherical.
  2. Ovalocytes: oval.
  3. Sickle cell: crescent.
  4. Poikilocytes: pear.
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11
Q

RBC’s size

A

Diameter: 6-9 micrometers in with an average of 7.5 (the median).
Thickness: 2.2 micrometers (edge) and 0.8 (center).

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12
Q

Abnormal sizes of RBC’s

A

Microcytes: less than 6 micrometers.
Macrocytes: more than 9 micrometers.
Anisocytosis: different sizes.

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13
Q

RBC’s LM

A

Unstained blood film: appear colored due to Hemoglobin.
Stained blood film: stained with leishmans stain, RBC’s are rounded, non nucleated and acidophilic (hemoglobin is a basic protein), with a pale center (1/3 of the diameter of RBC’s are Normochromic).

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14
Q

RBC rouleaux appearance

A
  1. RBC’s may adhere to each other resembling piles of coins.
  2. This process occurs in slow circulation (abnormal).
  3. Due to the surface tension caused by their biconcave surface.
  4. Reversible, no damage to cells.
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15
Q

Erythrocyte sedimentation rate (ESR)

A

The long chains of RBC’s sediment more easily. This is the mechanism for ESR, which increases non specifically due to inflammation.

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16
Q

RBC’s EM

A
  1. No nucleus
  2. No organelles
  3. Filled with hemoglobin: appears electron dense and homogeneous.
  4. Cell membrane is flexible
  5. Cytoskeleton (actin and spectrin): keeps stability of shape and membrane.
  6. Glycocalyx includes antigenic sites for blood groups (ABO) and RH factor.
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17
Q

Life span of RBC’s

A

120 days

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18
Q

Fate of RBC’s

A

Old RBC’s are phagocytosed by macrophages in the liver, bone marrow, and spleen. It is secreted as bile pigments while iron is reused to form new RBC’s.

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19
Q

Osmotic fragility of RBC’s

A

RBC’s maintain normal shape in plasma (isontonic solution: OP of 0.9% saline.
Crenation: if placed in hypertonic solution, they shrink and show notches.
Hemolysis: if placed in hypotonic solution, they swell, burst, and leak hemoglobin.
Remaining cell membrane is called Cell ghost.

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20
Q

How are RBC’s counted?

A
  1. Hemocytometer.
  2. Electronic counting instruments.
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21
Q

What is the number of RBC’s?

A
  1. Average number of RBC’s: 5 million/mm3
  2. Adult male: 5-5.5 million/mm3
    Stimulators effect of male hormones on the bone marrow.
  3. Adult female: 4.5-5 million/mm3
  4. Newborns: highest in newborns and decreases gradually.
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22
Q

Abnormalities in number

A
  1. Anemia
  2. Polycythemia
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23
Q

Anemia

A

Decreased number of RBC’s below 4 million/mm3 (oligocythemia) and/or decreased hemoglobin concentration.

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24
Q

What are types of anemia?

A
  1. Pernicious anemia.
  2. Sickle cell anemia.
  3. Aplastic anemia.
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25
Q

Pernicious anemia

A

Vitamin B12 deficiency anemia due to failed production of intrinsic factor by the stomach.

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26
Q

Sickle cell anemia

A

Abnormal rigid type of hemoglobin that accumulates at one side of the cell giving a crescent shape (Sickle RBC’s).

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27
Q

Aplastic anemia

A

Destruction of bone marrow Eg. By chemotherapy of irradiation. This leads to pancytopenia which is the decreased count of all blood cells).

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28
Q

Polycythemia

A

Increased number of RBC’s above 6 million/mm3. Due to hypoxia that stimulates the bone marrow to produce more RBC’s. It can be:
1. Physiological: high altitudes, muscular exercise, and in newborns.
2. Pathological: chronic lung and heart diseases.

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29
Q

Factors of adaptations of RBC’s

A
  1. Plasmalemma.
  2. Shape.
  3. Content: 33% Hemoglobin, 66% H2O, 1% enzymes.
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30
Q

Plasmalemma

A
  1. Flexible: to be squeezed inside narrow capillaries.
  2. Lipoproteins: highly selective for gas exchange.
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31
Q

Shape mode of adaptation

A
  1. Biconcave: increasing surface area for gas exchange.
  2. Rounded edges: easy passage in branched blood vessels.
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32
Q

Content mode of adaptation

A
  1. No nuclei or organelles: do not divide and give more space for hemoglobin.
  2. Enzymes (Hemoglobin reductase): combine O2 and carbonic anhydrase which will carry CO2.
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33
Q

Platelets (thrombocytes)

A

Small oval cytoplasmic fragments.

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34
Q

What is the origin of platelets?

A

Develop from megakaryocytes.

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35
Q

Platelets number

A

200,000- 400,000/mm3.

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36
Q

Platelets diameter

A

2-4 micrometers

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37
Q

Platelets LM

A

Oval, non nucleated fragments which have 2 zones:
1. Outer pale basophilic (clear) peripheral zone= hyalomere.
2. Central dark granular zone: granulomere.

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38
Q

Platelets EM

A

Cell membrane has a thick cell coat that helps platelets aggregation (platelet plug) to stop bleeding.

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39
Q

Hyalomere

A
  1. Cytoskeleton
  2. Membranous channels
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40
Q

Cytoskeleton hyalomere

A
  1. Microtubules: maintain cell shape.
  2. Actin microfilaments: help activated platelets to change shape and aid clot retraction.
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41
Q

Membranous channels hyalomere

A
  1. Open canalicular system: invaginations of cell membrane to release serotonin ( vasoconstriction of injured vessel).
  2. Dense tubular system: storage for Ca++.
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42
Q

Granulomere

A

Few mitochondria, ribosomes, glycogen (energy) and 3 types of granules:
1. a (specific) granules.
2. Delta (dense) granules.
3. Lambda granules.

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43
Q

a (specific) granules

A
  1. Clotting factors.
  2. Growth factors.
  3. Ca++.
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44
Q

Delta (dense) granules

A
  1. Serotonin.
  2. ATP.
  3. ADP.
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45
Q

Lambda granules

A

Lysosomes for clot removal after healing of vessels.

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46
Q

Purpura or Thrombocytopenia

A

Decreased number of platelets less than XX.

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47
Q

What are the causes of thrombocytopenia?

A
  1. Decreased production (bone marrow depression).
  2. Increased breakdown (autoimmune disease).
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48
Q

Thrombocytopenia is characterized by?

A
  1. Prolonged bleeding time.
  2. Excessive bleeding after minor trauma.
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49
Q

Erythrocytes types

A

One type

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50
Q

Leukocytes types

A

5 types.

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51
Q

Erythrocytes content

A

Not true cells nor organelles.

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52
Q

Leukocytes content

A

True cells with nuclei and organelles.

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53
Q

Erythrocytes number

A
  1. 4.5-5.5 million/mm3 in males.
  2. 4-5 million/mm3 in females.
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54
Q

Leukocytes number

A

4000-11000/mm3

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55
Q

Erythrocytes size

A

6-9 micrometers with an average of 7.5.

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56
Q

Leukocytes size

A

6-20 micrometers.

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57
Q

Erythrocytes life span

A

120 days.

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58
Q

Leukocytes life span

A

Days to years.

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59
Q

Erythrocytes osmotic fragility

A

Easily hemolysed.

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60
Q

Leukocytes osmotic fragility

A

Not easily hemolysed.

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61
Q

Erythrocytes origin and maturation

A

Bone marrow.

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62
Q

Leukocytes origin and maturation

A

Bone marrow and lymphoid tissue.

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63
Q

Erythrocytes shape

A

Biconcave discs.

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64
Q

Leukocytes shape

A

Spherical.

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65
Q

Erythrocytes functions

A

Gas exchange.

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66
Q

Leukocytes function

A

Defense

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67
Q

Erythrocytes motility

A

Nonmotile

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68
Q

Leucocytes motility

A

Motile.

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69
Q

Life span of granular leucocytes

A

Shirt life span (few days) and are compensated by new cells from the blood stem cells in the bone marrow.

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70
Q

Nucleus of granular leucocytes

A
  1. Single but segmented.
  2. Condensed nucleus with peripheral heterochromatin and central euchromatin.
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71
Q

Cytoplasm of granular leucocytes

A
  • Few organelles:
    1. Golgi apparatus.
    2. Mitochondria.
    3. rER.
  • Contain both non specific (azurophilic) and specific granules.
  • Azurophilic= affinity for azure dye (oxidized methylene blue).
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72
Q

Granular leucocytes are classified according to?

A

Affinity of their specific granules to stain.

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73
Q

Neutrophils are also called

A

Polymorphonuclear leucocytes (PMNs).

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74
Q

Neutrophils percentage

A

60-70%.

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75
Q

Neutrophils diameter

A

10-12 micrometers

76
Q

Neutrophils life span

A

Few days.

77
Q

Neutrophils LM nucleus

A

Single but segmented 2-5 lobes connected by thin chromatin thread. Dark and has many shapes (PMN).

78
Q

Neutrophils LM Barr body

A

Can be seen 3-6% of female cells.

79
Q

Neutrophils LM cytoplasm

A
  1. Specific granules: numerous fine, pale granules.
  2. Azurophilic granules: few, large, large, stain purple with azure dye.
80
Q

Neutrophils EM nucleus

A
  1. Peripheral heterochromatin.
  2. Small central euchromatin.
81
Q

Neutrophil EM cytoplasm

A
  1. Pseudopodia.
  2. Few organelles.
  3. More glycogen (energy).
82
Q

What are the two types of granules in neutrophils?

A
  1. Azurophil (primary).
  2. Specific (secondary).
83
Q

Neutrophils Azurophil granules

A
  1. Large, few, dark.
  2. Considered primary lysosomes.
  3. Contains myeloperoxidase defenses against bacteria and viruses.
84
Q

Neutrophils specific granules

A
  1. Small, many, pale.
  2. Contain:
    - Collagenase.
    - Phagocytin.
    - Lysozyme.
    - Lactoferrin.
85
Q

Functions of neutrophils specific granules

A
  1. Primary line of defense (non specific).
  2. Bacterial toxins attract neutrophils, which leave blood by migrating between endothelial cells of the blood vessels to C.T. By a process called Diapedesis to become motile and have pseudopodia (microphages).
86
Q

What do neutrophils do in the Connective tissue?

A
  1. Phagocytose bacteria
  2. Dead neutrophils form pus cells.
  3. Pus increases body temperature to stimulate heat regulating center in brain.
  4. Attract monocytes to site of infection.
  5. Stimulate bone marrow to form more neutrophils.
  6. Secrete trephone substances that help wound healing.
87
Q
  1. Phagocytose bacteria: specific granules.
A

Specific granules release their contents into phagocytic vesicle and C.T.:
1. Lactoferrin: binds to iron (essential for bacterial growth) (bacteriostatic).
2. Phagocytin: kill bacteria (bactericidal).
3. Lysozome: destroys bacterial proteins.
4. Collagenase: destroys collagen so facilitates movement of neutrophils.

88
Q
  1. Phagocytose bacteria: Azurophil granules.
A

Azurophil granules release their enzymes:
1. Myeloperoxidase: kill bacteria.
2. Other enzymes: cause bacteria’s lysis.

89
Q

Neutrophilia

A
  1. Increased percentage of neutrophils: X>75%.
  2. Due to pyogenic infection.
  3. Examples:
    - Acute tonsillitis.
    - Acute appendicitis.
    - Abscess.
90
Q

Neutropenia

A
  1. Decreases percentage of neutrophils: X<60%.
  2. It is due to:
    - Typhoid fever ( most common cause).
    - Tuberculosis (T.B.).
    - Viral infection as influenza.
91
Q

Eosinophils percentage

A

1-4%

92
Q

Basophils percentage

A

0-1%

93
Q

Eosinophils diameter

A

10-14 micrometers

94
Q

Basophils diameter

A

10-12 micrometers.

95
Q

Eosinophils life span

A

Few days

96
Q

Basophils life span

A

Few days

97
Q

Eosinophils LM

A

Nucleus: Biloed (horse-shoe shaped) connected by thick chromatin thread.
Cytoplasm: contain large acidophilic specific granules.

98
Q

Basophils LM

A

Nucleus: irregular segmented and S shape.
Cytoplasm: coarse basophilic granules which obscure the nucleus.
Metachromatically stained by toluidine blue: purple by heparin.

99
Q

Eosinophils EM

A

Nucleus: has peripheral heterochromatin with central euchromatin.
Cytoplasm: few organelles and two types of granules:
1. Azurophil: small= lysosomes.
2. Specific: oval with electron dense corse of basic proteins internum and less dense periphery externum, contains:
- Histaminase
- Sulphatase
- Eosinophil-derived neurotoxins

100
Q

Basophils EM

A

Nucleus: peripheral heterochromatin with central Euchromatin.
Cytoplasm: few organelles and two types of granules:
1. Azurophil: small = lysosomes.
2. Specific: large rounded electron dense that contains:
- Histamine
- Heparin
- Eosinphil chemotactic factor
- Leukotriens
Cell membrane shows receptors for IgE.

101
Q

Eosinophils functions

A
  1. Terminate Allergy:
    - Secrete histaminase and sulphatase to destroy histamine and heparin.
    - Phagocytose antigen-AB complexes.
  2. Defend against parasites:
    - Cytotoxic effect of internum: forms pores in their body.
    - Neurotoxins: nervous dysfunction of parasites.
102
Q

Basophils functions

A
  1. Secrete heparin: prevents clotting and promotes allergy.
  2. Secrete histamine: vasodilation that leads to sudden decrease in blood pressure and anaphylaxis.
  3. Attract eosinophils to the site of allergy by eosinophil chemotactic factor.
  4. Leukotriens: Brochospasm which leads to bronchial asthma.
  5. Limited phagocytic power.
103
Q

Eosinophilia

A

Increase in percentage: X>5% due to:
1. Allergic diseases: urticaria, eczema, and bronchial asthma.
2. Parasites: Bilharziasis.

104
Q

Eosinopenia

A

Decrease in percentage: X<1% due to:
1. Cortisone treatments: inhibit their release from bone marrow.

105
Q

Basophilia

A

Increase in percentage: X>1% due to:
1. Allergic diseases.
2. Parasitic diseases.
3. Viral infections like chicken pox.
4. Liver cirrhosis.

106
Q

Comparison between basophils and mast cells: life span

A

Basophils: few days.
Mast cells: longer (weeks to months).

107
Q

Comparison between basophils and mast cells: size

A

Basophils: 10-12 micrometers.
Mast cells: 20-30 micrometers.

108
Q

Comparison between basophils and mast cells: nucleus

A

Basophils: segmented.
Mast cells: round.

109
Q

Comparison between basophils and mast cells: phagocytosis.

A

Basophils: slight.
Mast cells: none.

110
Q

Comparison between basophils and mast cells: granules

A

Metachromatically stained due to histamine and heparin.

111
Q

Comparison between basophils and mast cells: surface receptor

A

Antibody Ig E

112
Q

No granular leucocytes are divided into:

A
  1. Lymphocytes.
  2. Monocytes.
113
Q

Monocytes percentage

A

3-8%

114
Q

Monocytes diameter

A

12-20 micrometers.

115
Q

Monocytes life span

A

3 days in blood and 3 months in C.T.

116
Q

Monocytes LM

A

Nucleus: large, eccentric, kidney, shaped, pale with 1 or 2 nucleoli.
Cytoplasm: non granular, non clear pale basophilic. Has frosted glass appearance due to lysosomes (Azurophil granules).

117
Q

Monocytes EM

A

Nucleus: Euchnomatic with clear nucleolus.
Cytoplasm:
1. Have pseudopodia.
2. Mitochondria.
3. rER
4. Well developed Golgi apparatus.
5. Many lysosomes.
Primary and secondary.

118
Q

Monocytes functions

A

Highly phagocytic cells:
1. Remain in the blood for 3 days.
2. Then they enter C.T. And change into macrophages to phagocytose bacteria and debris.
3. Antigen presenting cells.
4. The precursor of all phagocytic cells:
- Dust cells of lungs.
- Kupffer cells of the liver.
- Osteoclasts of the bone.
- Microglia of CNS.

119
Q

Monocytosis

A

Increased percentage of monocytes: X>8% due to chronic infections:
1. T.B.
2. Syphilis and glandular fever.
3. Monocytic anemia.

120
Q

Monocytopenia

A

Decreased percentage of monocytes: X<3% due to:
1. Pancytopenia.

121
Q

Lymphocytes percentage

A

20-30%

122
Q

Lymphocytes’ position in defense

A

2nd line of defense and 2nd most common cell of WBC’s

123
Q

Lymphocytes

A

Immune competent cells: have surface marks (receptors) for antigens.

124
Q

The two types of lymphocytes are divided according to?

A

Activity

125
Q

What are the two types of lymphocytes?

A

Small and large.

126
Q

Small lymphocytes percentage

A

15-20% of WBC’s.

127
Q

Large lymphocytes percentage

A

5-10%

128
Q

Small lymphocytes diameter

A

6-8 micrometers

129
Q

Large lymphocytes diameter

A

10-15 micrometers

130
Q

Small lymphocytes LM

A
  1. Nucleus: dark and filling the cell.
  2. Cytoplasm: little, pale basophilic rim around the nucleus.
131
Q

Large lymphocytes LM

A
  1. Nucleus: large, indented, pale with clear nucleolus.
  2. Cytoplasm: abundant, deeply basophilic.
132
Q

Small lymphocytes EM

A
  1. Nucleus: heterochromatic.
  2. Cytoplasm: many free ribosomes, two centrioles, and small Azurophil granules.
133
Q

Large lymphocytes EM

A
  1. Nucleus: euchromatic with prominent nucleolus.
  2. Cytoplasm: more mitochondria, rER, G.A., and lysosomes.
134
Q

Motility and distribution of lymphocytes

A
  1. Actively motile, continuously circulating between the blood and lymphatic organs where they settle.
  2. Only cells tat can return to blood.
  3. Found in blood, lymph, and lymphatic tissue.
135
Q

Classification of lymphocytes according to surface receptors

A

They have similar LM and EM.
1. T-lymphocytes.
2. B-lymphocytes.
3. Natural killer cells (NK cells).

136
Q

T-lymphocytes percentage

A

60-80%

137
Q

B-lymphocytes percentage

A

20-30%

138
Q

Natural killer cells percentage

A

5-10%

139
Q

T-lymphocytes life span

A

Years

140
Q

B-lymphocytes life span

A

Few days- few months.

141
Q

Natural killer cells life span

A

Years

142
Q

T-lymphocytes maturation site

A

Stems cells in the bone marrow migrate to thymus gland, differentiate and acquire receptors. (Thymi education).

143
Q

B-lymphocytes maturation site

A
  1. Bursa in fabricus birds.
  2. Bone marrow in mammals where they acquire receptors.
144
Q

Natural killer cells maturation site

A

Developed from precursors of T and B cells and do not mature in thymus.

145
Q

T-lymphocytes surface markers

A

T-cell receptors TCR Eg.
1. CD4
2. CD8 ptn

146
Q

B-lymphocytes surface marks

A

Receptors for:
Ig-M and Ig-D

147
Q

Natural killer cells surface markers

A
  1. CD 16 and others.
  2. Have neither T nor B cell receptors.
148
Q

T-lymphocytes function

A

Cell-mediated immunity

149
Q

B-lymphocytes functions

A

Humoral immunity

150
Q

Natural killer cells functions

A
  1. Innate early immunity (no T-helper cells stimulation).
  2. Similar to cytotoxic T-cells.
  3. Secretion of interferon (antiviral).
151
Q

T-lymphocytes types

A
  1. Cytotoxic CD8+ T-cells.
  2. Helper CD4+ T-cells.
  3. Regulatory (suppressor) T-cells.
  4. Memory T-cells.
152
Q

Cytotoxic CD8+ T-cells

A

Secrete perforins that produce pores in the membrane of virally-infected, transplanted, or neoplasticism cells killing the, directly (cell-mediated immunity).

153
Q

Helper CD4+ T-cells

A

Activate B-cells during humoral immune response.

154
Q

Regulator (suppressors) T-cells

A
  1. Maintain unresponsiveness to self-antigens.
  2. Suppress excessive immune responses.
155
Q

Memory T-cells

A

Rapid immune response on re-exposure to the same antigen (secondary immune response).

156
Q

B-lymphocytes functions

A

When exposed to specific antigen they become activated by T-helper cells to:
1. Plasmablasts then plasma cells to produce antibodies (Humoral immunity).
2. B memory cells responsible for the rapid second immune response.

157
Q

HIV

A

Human immunodeficiency virus that causes AIDS, destroys T-helper cells which leads to decreased immunity and patient becomes susceptible to infections.

158
Q

Lymphocytosis

A

Increased percentage of lymphocytes: X>30% due to:
1. Physiological in children.
2. Chronic infections:
- T.B.
- whooping coughing.
3. Leukemia

159
Q

Lymphocytopenia

A

Decreased percentage of lymphocytes: X<20% as in pancytopenia.

160
Q

Total leukocytic count

A

Total number of WBC of the blood: 4000-11000/mm3.

161
Q

How are leukocytes counted?

A
  1. Haemocytometer.
  2. Electron counting instrument.
162
Q

Abnormalities in total count of leukocytes

A
  1. Leucocytosis.
  2. Leukocytopenia.
163
Q

Leukocytosis

A

Increase in total number of WBC’s: X>11000/mm3.
1. Physiological: (transient): during pregnancy, labor, cold bath, and exercise.
2. Pathological: due to either acute or chronic infections.

164
Q

Leukocytopenia

A

Decreased total number of WBC’s: X<4000/mm3.
1. X-ray.
2. Irradiation.
3. Typhoid fever.
4. Influenza virus.
5. Excessive use of some antibiotics.

165
Q

Leukemia

A

Cancer that starts in the bone marrow which leads to a very high leucocytic count.
Peripheral blood shows abnormal forms of WBC’s with immature cells.

166
Q

Differential leukocytic count

A

The percentage of each type of WBC’s to the total number of leucocytes.
It is counted in a blood film stained with Leishman stain.

167
Q

Haempoiesis

A

Formation of blood cells in bone marrow and lymphatic organs. Eg: thymus.

168
Q

Bone marrow

A

Myeloid tissue.

169
Q

Types of one marrow

A

Red bone marrow and yellow bone marrow.

170
Q

Red bone marrow

A
  1. Active.
  2. Present in most bones of children.
  3. In adults: flat, short, and irregular bones.
171
Q

Yellow bone marrow

A
  1. Inactive.
  2. In shafts of long bones of adults.
  3. A store for fat.
  4. Can change into active if needed.
172
Q

Structure of the red marrow is composed of?

A
  1. Stroma.
  2. Free cells.
173
Q

Stroma

A
  1. Fixed cells.
  2. Blood sinusoids.
174
Q

Fixed cells

A
  1. Reticular cells and fibers form the network in the background.
  2. Fibroblasts.
  3. UMC.
  4. Pericytes.
  5. Osteogenic.
  6. Fat cells (the largest cells in the bone marrow).
175
Q

Blood sinusoids

A

Wide, irregular blood capillaries lined with endothelial cells with non-continuous basement membrane through their pores. Blood cells leave to the blood.

176
Q

Free cells

A
  1. Developing stages of the blood cells.
  2. The ratio of immature WBC’s to immature RBC’s is 5:1. Because the life span of WBC’s is shorter.
  3. Stem cells.
177
Q

What is the function of bone marrow aspirate or biopsy?

A

It is needed to diagnose disorders like aplastic anemia or leukemia.

178
Q

When is bone marrow transplantation needed?

A

The donation is needed in bone marrow diseases such as:
1. Leukemia: stem cells are taken from a donor are infused into the same or another.

179
Q

Reticulocytes size

A

Small: 9 micrometers.

180
Q

Reticulocytes are

A

Immature RBC’s but slightly larger.

181
Q

Reticulocytes cytoplasm

A

Acidophilic (Hb) with remnants of ribosomes and polysomes that form the reticulum.

182
Q

Reticulocytes in peripheral blood

A

Percentage X<=1%.

183
Q

When does the percentage of reticulocytes increase?

A

In cases of haemorrhage or destruction of RBC’s.

184
Q

Reticulocytes stain

A

Super vital stain: brilliant cresyl blue.

185
Q

Megakaryocytes size

A

Very large (mega) cells: 50-70 micrometers.

186
Q

Megakaryocytes nucleus and cytoplasm

A

Single, multiloed dark nucleus and basic cytoplasm.

187
Q

Megakaryocytes functions

A
  1. Invaginations of cell membrane forms demarcation channels dividing the cytoplasm into fragments that shed platelets. (Formation of platelets goody info).
  2. It extends pseudopedia (platelet ribbons) from which platelets detach.

Histology (5 decks)

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