Hematopoiesis & Erythropoiesis Flashcards

1
Q

blood volume in females

A

4-5L

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2
Q

blood volume in males

A

5-6L

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3
Q

blood pH

A

7.35-7.45

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4
Q

Blood composition (55%)

A

Plasma/Serum (fluid)

Water, proteins, other solutes

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5
Q

Blood composition (45%)

A

Formed elements (cells)

RBCs, WBCs, Platelets

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6
Q

Blood Specific Gravity

A

1.049-1.065

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7
Q

Centrifuge Blood Sample (Top, middle, bottom)

A

Top layer - Plasma/Serum

Middle - “Buffy Coat” - WBCs + platelets

Bottom Layer - RBCs

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8
Q

Hematocrit

A

% of packed red cells

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9
Q

Anticoagulant used

A

Plasma

Clotting factors present

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10
Q

Example of clotting factor

A

Fibrinogen

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11
Q

No anticoagulant used

A

Serum

Some clotting factors consumed

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12
Q

Gold/Red Top in a blood separation sample

A

No anticoagulant

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13
Q

Green/Purple/Blue - Blood Separation

A

Anticoagulant present

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14
Q

Blood Collection - Capillary

A

Adult - fingerstick

Baby - Heel stick

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15
Q

Blood Collection - Venipuncture

A

Median Cubital

Median Cephalic

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16
Q

Blood Collection - Arterial

A

Radial Artery

Brachial Artery

Femoral Artery

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17
Q

WBC Count (Conventional Units)

A

4.8-10.8 x 10^3/ microL

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18
Q

RBC Count - Male

A

4.7-6.1 x 10^6 / microL

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19
Q

RBC Count - Female

A

4.2-5.4 x 10^6 / microL

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20
Q

Hematocrit (HTC) Male

A

42-52%

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21
Q

Hematocrit (HTC) - Female

A

37-47%

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22
Q

Major Blood Functions

A

Transport oxygen to cells

Transport CO2 and wastes away

Provides defense

Regulates body pH, body temperature, fluid balance

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23
Q

Major blood functions are required to maintain

A

Homeostasis

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24
Q

Homeostasis

A

maintaining a constant environment or equilibrium

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25
Q

Hematopoiesis

A

Formation of blood cells

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26
Q

Hematopoiesis Characteristics

A

Takes place in hematopoietic tissue

Maintains a cell population of erythrocytes, leukocytes, platelets.

Responsible for the maturation and division of hematopoietic stem cells

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27
Q

Platelets

A

G

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28
Q

Erythrocytes

A

A

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29
Q

Neutrophils

A

I,E,C

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30
Q

Eosinophil

A

D

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31
Q

Basophil

A

J

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32
Q

Lymphocytes

A

B,H

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33
Q

Monocytes

A

F

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34
Q

Platelets (Thrombocyte)

Size?

Nucleus?

Average Life Span?

Function?

A

Size: 1-4 micro m

Cytoplasmic fragment, no nucleus

Average lifespan: 10 days

Function: homeostasis

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35
Q

Platelets Homeostasis

A

Process in which blood clots and bleeding is arrested

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36
Q

Neutrophil Function

A

Inflammation & Phagocytosis

1st line of defense against infections

Most abundant

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37
Q
A

Platelets (Thrombocyte)

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38
Q
A

Neutrophils

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39
Q

Neutrophil Nucleus

A

2-5 lobes connected by a thin filament

Segmentation allows passing through openings between lining cells

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40
Q

Neutrophil cytoplasm

A

light pink with secondary granules (pink/neutral)

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41
Q

Average life span neutrophils

A

6-10 hrs

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42
Q
A

Eosinophil

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43
Q

Eosinophil function

A

defense in parasitic and fungal infections

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44
Q

Eosinophil nucleus

A

bi-lobed with condensed chromatin

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45
Q

Eosinophil cytoplasm

A

secondary granules (reddish/orange)

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46
Q
A

Basophil

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47
Q

Basophil function

A

mediates allergic reactions

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48
Q

Basophil Nucleus

A

often obscured by large secondary granules

least abundant WBC in circulation

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49
Q

Basophil cytoplasm

A

dark secondary granules

  • histamine → vasoconstriction
  • Heparin → blood thinner

granules are water soluble

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50
Q

What do granules in basophils contain?

A

Histamine and Heparin (play a role in homeostasis)

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51
Q

histamine

A

vasoconstriction

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52
Q

heparin

A

blood thinner (anticoagulant)

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53
Q

Lymphocyte function

A

immune response and viral infection

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54
Q
A

lymphocytes

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55
Q

Lymphocyte nucleus

A

clumped chromatin

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56
Q

lymphocyte cytoplasm

A

stains blue, periphery more intense

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57
Q

Lymphocyte granules

A
  • usually none
  • can have a few (countable) azurophilic granules - reddish pink
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58
Q
A

Monocyte

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59
Q

Monocyte function

A

phagocytosis

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60
Q

Monocyte nucleus

A
  • Horseshoe-shaped/lima bean/convoluted
  • Lacy, fine chromatin

Shape/outline of monocyte is irregular

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61
Q

Monocyte cytoplasm

A
  • Dull gray-blue
  • Cloudy
  • Many small, red-purple staining granules
  • Vacuoles often present
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62
Q
A

A - Lymphocyte

B - Monocyte

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63
Q
A

A - Lymphocyte

B - Monocyte

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64
Q

Surrounding cells Lymph vs. Mono

A

Lymph - indented by RBCs

Mono - project pseudopods between or compressing nearby RBCs

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65
Q
A

Mature RBC - Erythrocyte

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66
Q

Major function of mature RBC

A

Oxygen transport from lungs to tissues

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67
Q

Shape of RBC

A

6-8 micro m Biconcave Disc (shallow middle)

Allows for max surface area for gaseous exchange

Hemoglobin is 95% dry weight

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68
Q

Mature RBC lifespan

A

120 day lifespan

Can travel 200-300 miles during this time

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69
Q

Organs within hematopoietic system

A

Bone Marrow

Liver

Spleen

Lymph Nodes

Thymus

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70
Q

Embryo Developmental Stage

A

Mesoblastic phase

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71
Q

Fetal Developmental Stage

A

Hepatic Phase

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72
Q

Birth Developmental Stage

A

Medullary Phase

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73
Q

Embryo - Mesoblastic phase

A
  • 2 weeks - 2 months gestation
  • Yolk sac - mesoderm layer
  • Forms primitive erythroid cells
  • Hemoglobin formed
    • Hgb Gower-1
    • Hgb Gower-2
    • Hgb Portland

All referred to as embryonic hemoglobin

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74
Q

Fetus - Hepatic Phase

A
  • 2 months - 7 months gestation
  • Liver and Spleen
  • Additionally forms WBCs and Megakaryocytes (platelets precursor)
  • Hgb formed
    • Fetal hemoglobin
    • Hemoglobin A1 (small amounts)
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75
Q

Birth - Medullary Phase

(bone marrow)

A
  • 7 months - rest of life!
  • Bone marrow = intramedullary hematopoiesis
    • Red marrow
  • Diapedesis
  • Hgb formed post birth
    • Hemoglobin A1
    • Hemoglobin A2 ( small amounts)
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76
Q

Infancy and Early Childhood

A

Volume of red marrow in infant and adult are approximately equal.

As one is aging, the distal long bones and axial skeleton is expanding

At 4 years, yellow marrow (fat) starts replacing red marrow → limits hemopoietic sites

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77
Q

Adolescence and Adulthood

A

Only active hemopoietic/red marrow in axial skeleton

  • Sternum
  • Ribs
  • Pelvis
  • Vertebrae
  • Skull

Other bones contain primarily yellow marrow

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78
Q

At the age of 40+

A

Only find hematopoietic/red marrow in:

  • Sternum
  • Ribs
  • Pelvis
  • Vertebrae
  • 50% red, 50% yellow marrow
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79
Q

Preferred bone marrow aspiration sites

A

Pelvis and Sternum

Last to be replaced by yellow marrow

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80
Q

Monophyletic Blood Cell Development Theory

A

All blood cells arise from one precursor cell that is multipotential or pluripoential and called stem cells

Considered Proven Theory

81
Q

Polyphyeltic Blood Cell Developmental Theory

A

Each blood cell comes from its own seperate precursor

Old Theory - Disproven

82
Q

Stem cells (Pluripotential vs multipotential)

A

Pluripotential → can develop into any cell line in the body

Multipotential → can develop into any blood cell line in the body

Cell stays in bone marrow until stimulus for development is given

Once stimulation, converts to a progenitor cell → committed to that cell line

83
Q

Cytokines

A

Soluble messages to tell early cells to differentiate

84
Q

Types of cytokines

A

Interleukins (IL) and Colony Stimulating Factors (CSF)

  • Mediate proliferation, differentiation, maturation of hematopoietic progenitor cells
  • One CSF or IL may affect more than one cell line or multiple stages within a cell line
  • May require combination to get needed effect
85
Q

Thrombopoietin

A

Stimulates CFU - Meg and causes release of platelets

86
Q

Erythropoietin

A

Stimulates CFU-E and regulates erythroid progenitor cells to mature

  • Glycoprotein produced by the peritubular interstitial cell in the juxtaglomerular apparatus (kidney tubules). Detects amount of oxygen
87
Q

Lymphoid stem cell (LSC) can differentiate into

A

T and B Cells

88
Q

T cells

A
  • Immune functions of cellular nature
    • cytotoxic
    • suppressing activities
89
Q

B cells

A

Immune Function → Antibody production

  • can further develop into plasma cells → secrete antibodies
90
Q

Myeloid Stem Cell

A

Develops into CFU-GEMM

91
Q

CFU-GEMM gives rise to

A

CFU-GM → CFU G and CFU M

CFU-Eo

CFU-Bas

CFU-Meg

CFU-E/BFU-E

92
Q

CFU G

A

Neutrophil

93
Q

CFU M

A

Monocyte/Macrophage

94
Q

CFU-Eo

A

Eosinophil

95
Q

CFU-Bas

A

Basophil / Mast Cell

96
Q

CFU-Meg

A

Thrombocytes

97
Q

BFU-E → CFU-E

A

Erythrocytes

98
Q

BFU?

A

Burst Forming Unit

99
Q

Normal Myeloid : Erythroid ratio

A

2:1 - 5:1

  • Myeloid → non-erythroid cells originating from myeloid stem cell (mainly granulocytes)
  • Erythroid → any erythroid stage

WBCs have a shorter life span than RBCs

100
Q
A

Erythrocyte maturation

101
Q

Erythroid nucleus & contents

A
  • Nucleus → site of DNA/RNA synthesis
  • Large → small/pyknotic as it matures
    • Chromatin
      • DNA, histones, proteins
      • Euchromatin → active/finely dispersed/nucleoli present
      • Heterochromatin → inactive/condensed nucleoli absent - more heterochromatin as it matures.

Eventually nucleus is extruded

102
Q

Immature Erythroid Cytoplasm

A
  • Small amount since nucleus is so big. High N:C ratio
  • Early stages have many ribosomes (RNA) - Basophilic cytoplasm
  • Within cytoplasm
    • Golgi zone → light staining near nucleus
    • Mitochondria → energy production and hemoglobin formation (Fe into heme ring)
103
Q

Mature Erythroid

A
  • As hemoglobin is formed, less and less RNA
    • Dark blue cytoplasm shifts to pink
  • N:C ratio decreases → eventually no nucleus
  • No golgi zone
  • no mitochondria
104
Q

Synchronous development

A

nucleus and cytoplasm mature at same rate

105
Q

Asynchronous development

A

Growth/maturation of nucleus and cytoplasm is not at the same rate

  • Abnormal development
  • Example: Megaloblastic anemia
106
Q
A

Megaloblastic anemia

107
Q

Erythrocyte Maturation - as RBC develops….

A
  • Cell volume decreases
  • N:C ratio decreases
  • Chromatin condense
  • Nucleoli disappears
  • RNA in cytoplasm decreases
    • Hemoglobin synthesis
      • gradually increases until a stopping point
108
Q

Erythrocytes capable of mitosis

A
  • Pronormoblast
  • Basophilic normoblast
  • Polychromatophilic normoblast
109
Q

Normoblast is also called

A

Rubriblast

110
Q

Pronormoblast is also called

A

Rubriblast

111
Q

Basophilic Normoblast is also called

A

Prorubricyte

112
Q

Polychromatophilic Normoblast is also called

A

Rubricyte

113
Q

Orhtochromatic normoblast is also called

A

Metarubricyte

114
Q

Polychromatophilic Erythrocyte (Macrocyte) is also called

A

DIffusely Basophilic Erythrocyte

115
Q

Erythrocyte is also called

A

erythrocyte

116
Q

Pronormoblast/Rubriblast

Size?

Nucleus?

Cytoplasm?

NC ratio?

BM%?

A

Size → 12-24 microm

nucleus → round, central. 2-3 nucleoli, fine diffuse chromatin (euchromatin)

Cytoplasm → stains deep blue (RNA). Often a visible golgi zone

117
Q
A

Pronormoblast/Rubriblast

118
Q
A

Pronormoblast/Rubricyte

119
Q
A

Pronormoblast/Rubricyte

120
Q
A

Pronormoblast/Rubriblast

121
Q

Basophilic Normoblast/Prorubricyte

Size?

Nucleus?

Cytoplasm?

NC ratio?

BM%?

A
  • size → 12-17 microm
  • Nucleus → Round, central, no nucleoli, some chromatin granularity
  • Cytoplasm → Slightly less Basophilic “cornflower blue”
  • NC ratio → 6:1 - 4:1
  • BM% → 1-5%
122
Q
A

Basophilic Normoblast/Prorubcricyte

123
Q

Pronormoblast vs. Basophilic Normoblast

Maturation differences

A
  • Less nucleoli
  • Beginning chromatin granularity
  • Cytoplasm less basophilic
  • golgi zone disappears
  • slightly smaller in size with decreasing NC ratio
124
Q
A

Pronormoblast

125
Q
A

Basophilic normoblast

126
Q

Polychromatophilic Normoblast / Rubricyte

Size?

Nucleus?

Cytoplasm?

NC?

BM%

A

Size → 10-15 micro m

Nucleus → round central, or slightly eccentric. Nucleoli - none. Chromatin is moderately compacted condensed “soccer ball”

Cytoplasm → hemoglobin synthesis beginning → stains lavender instead of blue

NC ratio → 4:1 - 2:1

BM → 5-30%

127
Q

Last stage capable of mitosis in Erythrocytes?

A

Polychromatic Normoblast / Rubricyte

Gives rise to 2 orthochromatic normoblasts

128
Q
A

Polychromatic normoblast / Rubricyte

129
Q

Basophilic normoblast vs Polychromatophilic Normoblast

Maturation differences

A
  • Nucleus can move off center
  • chromatin more mature and begins to become pyknotic
  • Cytoplasm shifts from blue to purple (hemoglobin)
  • Slight smaller in size and NC ratio
130
Q
A

Polychromatophilic Normoblast

131
Q

Orthochromatic Normoblast / Metarubricyte (aka nBRC)

size?

Cytoplasm?

NC ratio?

BM%

A

size → 8 -12 micro m

nucleus → Last nucleated stage. Round, central or eccentric. Completely pyknotic dark chromatin. “Most perfect circle”

Cytoplasm → Pink or slightly purple cytoplasm. Hemoglobin increasing main constituent. RNA decreasing

NC Ratio → 1:1 - 1:2

BM% → 5-10% can be found in circulation of newborns in normal conditions

Cannot divide further

132
Q
A

Orthochromatic Normoblast

133
Q
A

Orthochromatic Normoblast

134
Q
A

Orthochromatic normoblast

135
Q

Polychromatophilic Erythrocyte (Macrocyte) / Diffusely Basophilic Cell

Size?
Nucleus?

Cytoplasm?

A

Size → 8-10 micro m

Nucleus → NONE

Cytoplasm → blue/gray (due to Polychromatophilia), due to residual RNA. Contains mitochondria, loses organelles within 48 hrs in maturation to mature RBC

Last stage to synthesize hemoglobin

136
Q

Last stage to synthesize hemoglobin?

A

Polychromatophilic Erythrocyte

137
Q
A

Polychromatophilic Erythrocyte

138
Q
A

Polychromatophilic Erythrocyte

139
Q

Orhochroamtic Normoblast → Polychromatophilic Erythrocyte

Maturation Differences

A
  • Nucleus leaves
  • cytoplasm is similar in color - pink/purple
  • Cell is similar in size
140
Q

Wrights stain

A

Polychromatophilic Erythrocyte

141
Q

New Methylene Blue (Vital Stain)

A

Reticulocyte

142
Q

Erythrocyte

Size?

Nucleus?

Cytoplasm?

A

Size → 7-8 micro m

Nucleus → none

Cytoplasm → pink with central pallor

Found in peripheral blood

No longer able to synthesize new hemoglobin (no mitochondria present)

143
Q
A

Mature Erythrocytes

144
Q

Polychromatiophilic Erythrocyte → Erythrocyte

Maturation Differences

A
  • Cytoplasm loses purple tinge
  • Central pallor develops
  • slightly smaller in size
145
Q

RBC membrane - Permeability

A
  • Selective barrier
    • Water and anions (-) → passive diffusion
    • Cations (+) and other substances → active transport
      • Potassium primarily found inside the RBC (25:1)
      • Sodium is primarily found outside the RBC (1:12)
    • ATP depletion leads to loss of gradient and cell dehydration
  • Crucial in
    • Controlling RBC volume
    • Preventing Colloid Osmotic Hemolysis
146
Q

RBC membrane - Composition

A
  • Highly Elastic → capable of membrane extension
  • Chemical composition
    • 50% proteins
    • 40% phospholipids and glycolipids
    • 10% cholesterol
147
Q

Layers of RBC membrane

A
  1. Outer Hydrophilic Portion → Contains glycolipid, glycoprotein and protein
  2. Central Hydrophobic Portion → Contains protein, cholesterol, phospholipids
  3. Inner Hydrophilic Layer → contains protein
148
Q

Cholesterol in the membrane

A
  • Equally distributed across the central hydrophobic layer → 25% of RBC membrane lipids

Provides continual exchange with plasma cholesterol → affected by body lipid transport

If abnormal, can affect RBC morphology

149
Q
A

Acanthocytes

150
Q

Choline phospholipids

A
  • Phosphatidyl choline + sphongomyelin
  • Located on outer half bilayer → closer to the plasma
151
Q

Amino Phospholipids

A

Phosphatidylethanolamine and Phosphatidyl Serine

Almost exclusively on inside layer of bilayer

If outside, can initiate clotting mechanism

152
Q

Integral Membrane Proteins

A

Traverse entire membrane from outer surface to the inner cytoplasmic side

Ex: Glycophorin

153
Q

Glycophorin in membrane

A
  • 20% of total membrane proteins
  • composed of 60% carbohydrate
  • Contributes most of the membrane sialic acid
    • causes RBC to have a negative charge that makes them repel each other in the bloodstream
154
Q

Peripheral Membrane proteins

A

Cytoplasmic surface of the membrane

Beneath bilayer and forms cytoskeleton

Ex: Spectrin

155
Q

RBC Cytoskeleton - Inner Hydrophilic Layer

A

Provides rigid support and stability to bilayer

Responsible for deformability of membrane

156
Q

Major component of RBC Cytoskeleton Inner Hydrophilic Layer

A

Spectrin

Ankyrin

Actin

Adducin

Other cytoskeletal proteins

157
Q

Most important and abundant peripheral membrane protein

A

Spectrin

158
Q

Spectrin - Inner Hydrophilic Layer

A

25-30% of total membrane protein

Makes up 75% of cytoskeleton

Binds other peripheral proteins to make skeletal network

159
Q

RBC Deformability

A

Critical for RBC survival through microvasculature + Oxygen deliver function

160
Q

Depleted ATP

A

Spectrin phosphorylation decreases → loss of deformability

Increased calcium accumulation and membrane deposition → increased rigidity

161
Q

Primary Function of Hemoglobin

A

Delivery and release of oxygen to the tissues

Facilitation of carbon dioxide

162
Q

Hemoglobin weight in RBC

A

33% of RBC by volume

95% of RBC dry weight

163
Q

Male Hemoglobin Normal Range

A

14-18 g/dL

164
Q

Female Normal Hemoglobin Range

A

12-16 g/dL

165
Q

Infant Normal Hemoglobin Range

A

14-22g/dL

166
Q

What does hemoglobin consist of?

A

4 heme rings + 4 iron molecules + 4 globin chains

167
Q

Hemoglobin synthesis starts in nucleated RBC stage

Hemoglobin synthesis is dependent on:

A
  1. Synthesis of protoporphyrins (precursor of heme)
  2. Adequate iron delivery and supply
  3. Adequate globin synthesis

65% occurs during nucleated (immature) RBC stages

35% occurs during polychromatophilic erythrocyte / reticulocyte stage

168
Q

1 heme ring =

A

1 porphyrin = 4 pyrrole rings

169
Q

Primary hemoglobin structure

A

number and sequence of amino acids in each globin chain

170
Q

secondary hemoglobin structure

A

twisting of the amino acid chain (2D helical)

171
Q

Tertiary hemoglobin structure

A

bending the twisted amino acid chains into 3D shape (pretzel shape)

172
Q

Quartenary hemoglobin structure

A

Assembling each 3D chain with heme groups

Complete, functional hemoglobin molecule

173
Q

Hemoglobin A1

A

2 alpha + 2 beta

Most abundant → 95-98%

174
Q

Hemoglobin A2

A

2 alpha + 2 delta

2-5%

175
Q

Hgb F

A

2 alpha + 2 gamma

Fetal hemoglobin

Less than 2%

176
Q

Abnormal hemoglobin - unable to carry oxygen

A
  1. MetHemoglobin
  2. Carbocyhemoglobin
  3. Sulfhemoglobin
177
Q

MetHemoglobin

A
  • Iron is. oxidized to Ferric State (Fe3+) → no longer binds oxygen
  • Reversible through strong reducing substance administration
  • Example Causes: ingestion of strong oxidant drug/enzyme deficiency
178
Q

Carboxyhemoglobin

A
  • Oxygen is replaced with carbon monoxide (CO) → binding is x200 stronger
  • Reversible through inhalation → oversaturate blood with oxygen
  • Example causes: car running in garage
179
Q

Sulfhemoglobin

A
  • Sulfur is incorporated into heme structure
  • Irreversible
  • Example Causes: Ingestion of sulfur containing drugs/ chronic constipation
180
Q

90% of RBCs energy (ATP) comes from

A

Non-oxidative pathways.

Even through it carries oxygen to other cells to be used for energy

181
Q

3 phases of Erythrocyte lIfe

A
  1. Erythropoiesis of RBC production
  2. Release from marrow to circulation
  3. Destruction and death
182
Q

Reticuloendothelial System (RES)

A

Cellular and immunologic defense system in the body → detects if something is wrong in RBC

Phagocytic cells (Histocytes, monocytes, macrophages) in → spleen, liver, lymph nodes, bone marrow

Helps to remove RBC’s from circulation

183
Q

Primary site of RBC phagocytosis

A

spleen

184
Q

Spleen - Home to littoral cells

A

most sensitive detectors for RBC abnormalities

  • Example of RBC abnormalities →
    • Senescent (old), nearing 120 life span → membrane loses deformability and elasticity
    • Abnormal RBC morphologies and inclusions
    • RBC coated in antibodies

Additional function → sequestering (separately storing) ⅓ platelets and granulocytes

185
Q

Removal of inclusions is called

A

pitting

186
Q

removal of RBC from circulation is called

A

culling

187
Q

RBC destruction and contents released

A

Hemolysis

188
Q

RBC hemoglobin is broken down into

A
  1. Fe molecule - put back into plasma iron pool (reused)
  2. Globin - degraded for protein to amino acid (reused)
  3. Polyphyrin (heme) ring - has to be metabolized by the body to an excretable form (not reused)
189
Q

Extracellular Hemolysis

A

RBC broken w/i RES system

90% of RBC destruction under normal conditions

190
Q

Intracellular hemolysis

A

RBC lyses in blood vessel

10% of RBC destruction under normal conditions

191
Q

How does extracellular hemolysis work

A
192
Q

Extra vascular hemolysis process (slide46/53)

A

Within RES

  • Heme disassemble to Biliverdin
  • Biliverdin converted to Unconjugated Bilirubin aka indirect Bilirubin

Released to blood and carried by albumin to liver

Within hepatocyte of liver

  • Unconjugated Bilirubin is conjugated → Conjugated Bilirubin “Direct Bilirubin”

Urobilinogen then

  • is eliminated in the stool
  • Reabsorbed into blood and excreted by the kidneys in urine
193
Q

Intravascular Hemolysis Process ( slide 57/53)

A

Hemoglobin Released in blood vessel

  • Circulates → Hemoglobinemia
    • Filtered at the kidney → Haptoglobinuria
  • Carried by Haptoglobin to Liver
    • Proceeds with extravascular hemolysis
  • Gets oxidized to methmoglobin
    • Globin seperates
    • Metheme
      • Stays together and binds abumin - Methemalbumin and carried to liver
        • seperates
          • Hemopexin carries heme to liver
            • iron is recycled
194
Q

Erythropoiesis is sustained in a steady state

A

Equal amounts of red cell production and destruction daily

Both equal about 1%

195
Q

Erythropietin

A

When less oxygen is being delivered to the kidneys (EPO) is being released. It is a hormone that goes to bone marrow and produces more RBC

196
Q

When do we need more RBC?

A

in increase in oxygen demand / decrease in oxygen tension

ex: blood loss / anemia / high altitudes

197
Q

If the bone marrow cannot keep up with RBC needs

A

Hematopoiesis starts to occur elsewhere (ex: liver and spleen) → Extra-medullary Hematopoiesis

198
Q

Hormonal influences that decrease Erythropoiesis

A

When these are low → low erythropoiesis

  • Hypopituitarism
  • Hypothyroidism
  • Hypoadrenalism (Addison’s Disease)
199
Q

Hormonal influences that Increase Erythropoiesis

A

When these are high → high RBC production

  • Hyperadrenalism (Cushings disease)
  • Increased estrogen
  • Increased androgens