HEMOGLOBIN METABOLISM Flashcards
1
Q
_____________is a highly studied protein found in red blood cells
(RBCs) and makes up around ______ of the content within RBCs.
● Hemoglobin within RBCs is stable, protecting it from denaturation and
kidney excretion, whereas free hemoglobin outside of RBCs has a
short lifespan
A
HEMOGLOBIN
95%
2
Q
Its main role is to transport oxygen from the lungs to body tissues and
carry carbon dioxide from tissues to the lungs for exhalation.
A
Hemoglobin
3
Q
Hemoglobin contributes to____________ by binding and
releasing hydrogen ions
A
acid-base balance
4
Q
It also participates in the regulation of vascular tone by transporting __________
A
Hemoglobin
nitric oxide
5
Q
____________is made up of a ring of carbon,
hydrogen, and nitrogen atoms called
_______________with a central atom of
divalent ferrous iron (Fe²⁺).
A
heme - protoporphyrin IX
6
Q
Each of the four heme groups is positioned in
a pocket of the ____________ near the
surface of the hemoglobin molecule.
A
polypeptide chain
7
Q
__________ in heme binds reversibly with
one oxygen molecule. When it’s oxidized to
the __________ it can no longer bind
oxygen, leading to the formation of
___________
A
Ferrous iron - ferric state (Fe³⁺), - methemoglobin.
8
Q
_______________ consists of four globin chains that are categorized
into two identical pairs of unlike polypeptide chains.
A
Hemoglobin
9
Q
In globin structures These chains are designated using ___________
A
Greek letters
10
Q
Each globin chain contains __________ separated by seven
nonhelical segments, connecting the helices.
A
eight helices
11
Q
Hemoglobin can be described by its primary _________________
secondary _________________, tertiary ________________ quaternary____________________
A
primary (amino acid
sequence), secondary (arrangement of helices and nonhelices),
tertiary (pretzel-like configuration), and quaternary (complete
hemoglobin molecule) protein structures
12
Q
The quaternary describes the ___________, which is _____________
attached to four polypeptide chains. It can carry up to four
molecules of oxygen.
A
complete hemoglobin molecule
spherical and contains four heme groups
13
Q
The kidneys detect hypoxia and respond by producing
______________, a hormone.
A
erythropoietin (EPO),
14
Q
EPO signals the ____________ to produce more ____________ and ____________
A
bone marrow
red blood cells
accelerates hemoglobin synthesis.
15
Q
This process increases the oxygen-carrying capacity of the
blood, alleviating the hypoxia
A
EPO
16
Q
Hemoglobin reference values can vary, but typical levels are
_____________ for men, ____________ and higher
for _____________
A
13.5-18.0 g/dL - men
12.0-15.0 g/dL for women
higher - newborns.
17
Q
3 HEMOGLOBIN FUNCTION
A
● OXYGEN TRANSPORT
● CARBON DIOXIDE TRANSPORT
● NITRIC OXIDE TRANSPORT
(OCN)
18
Q
Hemoglobin’s primary function is to ___________, ___________, ___________
A
bind oxygen in the lungs (high
oxygen affinity), transport oxygen, and efficiently release oxygen to
body tissues (low oxygen affinity)
19
Q
Each of the four heme iron atoms in hemoglobin can reversibly bind
one oxygen molecule, with approximately __________of oxygen bound
per gram of hemoglobin.
A
1.34 mL
20
Q
Hemoglobin’s affinity for oxygen
depends on _____________
A
the partial pressure of
oxygen (PO2)
21
Q
__________ is sigmoidal, indicating that
hemoglobin has low oxygen affinity
at low oxygen tension (tissues)
and high affinity at high oxygen
tension (lungs)
A
curve
22
Q
OXYGEN TRANSPORT
A PO2 of around _________ results in 50% oxygen saturation
of hemoglobin. A ________in the curve occurs when ______ saturation
happens at a lower PO2, while a
right shift indicates _________saturation
at a higher PO2.
A
27 mmhg - left shift and right - 50%
23
Q
Myoglobin, found in __________ and ________, is a
monomeric, high-affinity oxygen-binding heme protein with a
hyperbolic oxygen dissociation curve
A
cardiac and skeletal muscle
24
Q
___________ releases oxygen only at very low partial
pressures, making it less effective than hemoglobin at
delivering oxygen to tissues at physiologic oxygen tensions.
A
Myoglobin
25
Elevated serum myoglobin levels can indicate ______________, __________, __________, ____________
muscle damage in myocardial infarction, trauma, or rhabdomyolysis,
and in renal failure,
26
myoglobin may be present in ____________
urine.
27
_____________ the main hemoglobin in newborns, has a left-shifted
oxygen dissociation curve (higher oxygen affinity) compared
to Hb A.
Hgb F
28
This difference is due to a specific amino acid variation in
the 2,3-BPG binding site between the _____ and ________
γ and β chains - Hgb F
29
______________aids in extracting oxygen from
the maternal circulation but may hinder oxygen delivery to
tissues.
Hb F's high oxygen affinity
30
__________ have a higher RBC count, hemoglobin
concentration, and hematocrit compared to adults, gradually
decreasing to adult levels by ___________ as Hb F is replaced
by Hb A
Newborn
6 months
31
_______________is produced by vascular endothelial cells and
causes relaxation of smooth muscle in the vascular walls,
leading to vasodilation
Nitric oxide
32
_______________ has a very short half-life, but some enters
red blood cells (RBCs) and can bind to _______ in the beta
chain of hemoglobin. This binding forms _____________
Free nitric oxide
cysteine
S nitrosohemoglobin
33
● Hypoxic Vasodilation Theory:
This process stimulates vasodilation and increases blood flow, a
phenomenon known as ____________
hypoxic vasodilation.
34
Some researchers propose that hemoglobin acts to _______________
preserve and
transport nitric oxide to hypoxic microvascular areas
35
Hemoglobin may work in conjunction with other systems to
regulate _________________
local blood flow to microvascular areas.
36
● Hypoxic Vasodilation Theory:
It can bind and inactivate nitric oxide, causing ____________
and decreased blood flow when oxygen levels are high.
vasoconstriction
37
Conversely, it can release nitric oxide, causing _____________ and
increased blood flow when oxygen levels are low.
vasodilation
38
WHAT ARE THE THREE DYSHEMOGLOBINS
● METHEMOGLOBIN
● SULFHEMOGLOBIN
● CARBOXYHEMOGLOBIN
39
______________ is formed through the reversible oxidation of
heme iron to the ferric state (Fe³⁺)
Methemoglobin
40
limit methemoglobin accumulation
NADH-cytochrome b5 reductase pathway
41
______________ cannot transport oxygen
Methemoglobin
42
● METHEMOGLOBIN
At levels exceeding __________ of total hemoglobin, _______
(bluish skin and mucous membrane discoloration) and
__________ symptoms may occur
Levels above _______ can lead to_____________
30% - cyanosis and hypoxia
50% - coma and death.
43
Methemoglobinemia (elevated methemoglobin levels) can be
__________ or __________
acquired or hereditary
44
Acquired: ____________, __________, ____________, ________, ____________
○ Hereditary: ______________, ____________
○ Acquired: exposure to external oxidants, such as nitrites,
primaquine, dapsone, or benzocaine
○ Hereditary: Cytochrome b5 reductase deficiency and Hb M
(M hemoglobin)
45
● METHEMOGLOBIN
Blood with high levels of methemoglobin takes on a
_________________ and does not revert to the typical ______________after oxygen exposure.
chocolate brown color - red
color
46
The formation of sulfhemoglobin involves adding a sulfur atom to the
pyrrole ring of heme, resulting in a ___________
greenish pigment.
47
individuals with elevated levels exhibit___________ (a bluish discoloration of
the skin).
cyanosis
48
○________________ cannot be converted back to normal Hb A
sulfhemoglobin
49
irreversible oxidation of hemoglobin by certain drugs (such as
__________, ______________, ______________, __________) or exposure to
sulfur-based chemicals in industrial or environmental settings
● SULFHEMOGLOBIN
sulfanilamides, phenacetin, nitrites, and phenylhydrazine
50
___________ is formed when carbon monoxide (CO) binds to heme iron
COHb - carboxyhemoglobin
51
_____________ has a much higher affinity for hemoglobin (240 times) compared to
oxygen. This affinity shift impairs the release of oxygen to body tissues
Carbon monoxide
52
Carbon monoxide is often referred to as the ____________ because it's ____________ and _________ making its presence hard to detect. Victims may quickly become __________
(oxygen-deprived).
"silent killer"
odorless and colorless
hypoxic
53
Toxic effects start to appear at COHb levels of ___________, including symptoms like
_____________, _________, _____________
20-30% - headache, dizziness, and disorientation - Carboxyhemoglobin
54
COHb levels exceeding __________ of total hemoglobin can result in __________, ____________, ___________, _________, ____________, __________
40% - coma, seizures, low - carboxyhemogloin
blood pressure, cardiac arrhythmias, pulmonary edema, and may lead to death.
55
● Treatment involves removing the source of carbon monoxide exposure and
administering _____________ to facilitate the displacement of CO from hemoglobin
100% oxygen - CARBOXYHEMOGLOBIN
56
Red blood cells A. K. A.
aka Erythrocytes
57
Size of erythrocytes
7-8um
58
RBC average
7.2um
59
RBC Shape:
Biconcave Disc
60
RBC Lifespan:
90-120 days
61
RBC Function:
Efficient transport of oxygen from the lungs to the tissues,
and carbon dioxide from the tissues to the lungs
62
Hemoglobin
@Oxyhemoglobin
@Deoxyhemoglobin
63
Most hemoglobin found on the ___________
periphery
64
RBC
__________ volume
__________ surface area
* 90fL volume
* 140um2 surface area
65
Very thin cell membrane
* Large surface area compared to
volume
RBC
66
RBC is composed of ___________ proteins, ______lipids, ________ carbohydrates
52%, 40%, 8%
67
To separate the intracellular fluid
environment from the extracellular fluid
environment
RBC Membrane
68
Allow nutrient and ion passage selectively
in and out of the cell
RBC Membrane
69
➤Allow the cell to deform when required
RBC Membrane
70
✩ Helical configuration
✩ ɑ and ꞵ spectrin
71
✩ Anion exchanger
✩ Band 3
72
✩ Stabilizes the linkage of ankyrin to band 3
✩ Band 4.2
73
✩ Transmembrane
✩ Gives RBC a negatively
charged surface
✩ Glycophorin C
74
Water transporter
Aquaporin 1
75
Anion transporter, support system for surface antigens of ABH blood group antigens
Band 3
Anion exchanger 1
76
Ca 2+ transporter
Duffy blood group antigens
77
Glucose transporter, supports ABH blood group antigens
GLUTI
78
transports negatively charged sialic acid, supports MN blood group antigens
Glycophorin A
79
Transports negatively charged sialic acid, supports Ss blood group antigen
Glycophorin B
80
Transports negatively charged sialic acid, supports Gerbich blood group antigen
Glycophorin C
81
Integrin adhesion
ICAM 4
82
Zn 2+ binding endopeptidase supports kell blood group antigens
Kell blood group antigens
83
urea transporter
Kidd blood group antigens
84
Supports D and Cc Ee blood group antigens
Rh blood group antigens
85
Supports DCcEe antigen expression, gas transporter
Rh antigen expression proteins
86
accurate balance of intracellular K+, Na+ and Ca2+
Electrolytes
87
glucose, intermediate products of glycolysis
Metabolic Materials
88
glycolytic enzymes
Enzymes
89
Produces _________ of glucose energy used
by RBCs
_______ molecules of ATP are consumed
________ molecules of ATP are produced for
each molecule of glucose
EmbdenMeyerhof Pathway
90%
2 molecules
4 molecules
90
EmbdenMeyerhof Pathway
1.
2.
3.
1. Hexose Monophosphate Pathway
2. Luebering Rapoport Pathway
3. Methemoglobin Reductase Pathway
(HLM)
91
Hexose Monophosphate Pathway also known as _____________
*Pentose Phosphate Pathway
92
Functions of Hexose Monophosphate pathway
*Functions:
*Protects hemoglobin from oxidative stress by
generating NADPH
93
provides the only means of generating NADPH
for glutathione reduction, and in its
absence erythrocytes are particularly vulnerable to
oxidative damage.
G6PD
94
____________ is able
to detoxify oxidative
compounds and safeguard
hemoglobin, sulfhydrylcontaining enzymes, and
membrane thiols, allowing
normally functioning RBCs
to carry enormous
quantities of oxygen
safely
Normal G6PD activity
95
Glucose-6-Phosphate
Dehydrogeanse
Deficiency
*Heinz Bodies
96
* Functional Iron
* FERROUS (Fe2+)
97
* Oxidative Form
* FERRIC (Fe3+)
98
* Prevents oxidation of iron
* Maintains iron in FERROUS
STATE
Methemoglobin Reductase
Pathway
99
◊ regulation of oxygen release in the tissues
◊ generation 2,3-Diphosphoglycerate (2,3-DPG
Luebebering rapoport pathway
100
What happens to the
RBCs when they reach
senescence
✩Membrane becomes less flexible
✩Concentration of cellular hemoglobin increases
✩Enzyme activity diminishes
101
Maintains cellular energy by generating ATP
Embden-Meyerhof Pathway
102
Prevents denaturation of the globin molecule by oxidation
Oxidation or Hexose Monophosphate pathway
103
Prevents oxidation of heme iron
Methemoglobin reductase pathway
104
Regulates oxygen affinity of hemoglobin
Luebebering rapoport pathway
105
The men who started automation
Wallace H. Coulter (1913-1998)
Joseph R. Coulter (1924 -1925)
106
Why automation is important?
Cell counting
Diagnosis of hemoglobinopathies
Immunophenotyping
Diagnosis of leukemia and lymphoma
Coagulation of abnormalities
107
Automation advantages
1. Speed and efficient handling
2. Greater accuracy and precision
3. Multiple test on single platform
4. More workload and management
5. More timely diagnosis
108
Disadvantage of automation
1. Flagging
2. RBC morphology
3. Erroneous results
4. Expensive
109
2 Types of Hematology Analyzers
1. Semi-automated
2. Fully automated
110
1. Measures only few parameters
2. Some steps like dilution carried out manually
Semi-automated
111
1. Measures multiple parameters
2. Required only coagulation of blood samples
Fully automated
112
3 Basic Components of
Hematology Analyzer
1. Hydraulics
2. Pneumatics
3. Electricals
113
MAHADD
Mixing chambers
Aperture bath
Hemoglobinometer
Aspirating unit
Dispenser
Dilution
Hydraulics
114
Vacuum and pressure for operating valves
Pneumatics
115
Analyzers and Computing Circuitry
Electricals
116
3 Principles automated blood analyzers
Electrical impedance
Light scatter
Fluorescence
117
Detection and measurement of changes in electrical produced by cells as they traverse a small aperture
Coulter principle
118
______________ is composed of electrically conductive diluent
Solution
119
________ filled with a conductive buffered electrolyte solutions separatedby
glass tube having a small aperture
2 chambers
120
____________ is generated between the internal and external electrode
direct current
121
______________ is smaller than the WBCaperture
Aperture for RBC/platelet
122
provides a sample stream surrounded by a sheath fluid as cells pass through the aperture
Hydrodynamic Focusing
123
Coincident passage of cells
Reciculation of cells
Hydrodynamic focusing prevents
124
3 Variables measured
Platelet distribution Width
by Electrical
Impedance
WBC
RBC
Platelet
125
➟ Diffraction of light
➟ Cell volume
ᴥ Forward Angle Scatter
126
➟ a.k.a. Orthogonal Light Scatter
➟ Refraction and reflection of light
➟ Internal structures of the cell
ᴥ Side Scatter Light
127
➟ Differential scatter
➟ Cellvolume
Forward Low Angle
Scatter/Forward High Angle
Scatter
128
Emits a monochromaticlight
LASER
129
*Light is scattered in different directions:
Absorption
Diffraction
Refraction
Reflection
130
Light Source: _____________
Tungsten Halogen Lamp or Halogen-Neon LASER
131
___________ are
provided to prevent nonscattered light from
entering the detectors
Lens blockers
132
3 Variables measured by Optical
Light Scatter
RBC count
Mean Cell Volume
5 Part WBC differential
133
Measures multiple cellular and fluorescent properties of cells when they flow as a single suspension through a laser beam
Fluorescent Flow Cytometry
134
– internal cell structure
*Side Scatter Light
135
– RNA/DNA information
Side Fluorescence Light
136
– cell volume
*Forward Scatter Light
137
The sample is injected into a
stream of sheath fluid within the
flow chamber
Fluidics (the Flow System)
138
3 Components of Fluorescent Flow Cytometry
Fluidics (the Flow System)
OPTICS
ELECTRONICS
139
➥ Cells are hydrodynamically
focused
Fluidics (the Flow System)
140
immunophenotyping analysis
➥ High flow rate =
141
DNA analysis
Low flow rate
142
➥ LASER light is required
to excite the cells
➥ Light Scattering
➥ Fluorescence (Light
Emission)
OPTICS
143
A system of optical mirrors and filters then
direct the specified wavelength of light to
the designated photodetectors
OPTICS
144
➥ Converts optical signals
(photons) to
corresponding electronic
signals (electronics)
ELECTRONICS
145
_________Is proportional
to the amount of light
striking a cell
Electronic signal
146
__________ is collected and
stored in the computer
data
147
histogram
✩Single parameter
148
data plot
✩Two parameters
149
✧Boundary that can be set
to restrict the analysis to a
specific population within
the sample
Gating
150
✧Data selected by the gate is
then displayed in
subsequent plots
Gating
151
□ Consists of collecting cells
of interests
Sorting
152
Defined through criteria
of size and fluorescence
Sorting
153
Classification of reticulocytes into 3 maturationstages:
a. LowFluorescenceReticulocytes
b.Middle FluorescenceReticulocytes
c.High FluorescenceReticulocytes
154
3 Other Methods
Peroxidase
Fluorescence
Immunological
(PFI)
155
* Identification and counting of granulocytes
* Lymphocytes are not stained
* Peroxidase
156
* Reticulocytes and platelets
* Best for detecting immature platelets
Fluorescence
157
* Accurate platelet counting using CD41/CD61 antibodies
Immunological
158
Graphical representation of
numerical data of different cell
populations in a cell counter
HISTOGRAM
159
Histogram Gives information on:
✓Average size of cell
✓Distribution of size
160
_________________ separates the distribution curve for the volume
Discriminators
161
WBC Discriminator
* LD = _________
* UD = fixed at _________
RBC Discriminator
* LD = _________
* UD = ____________
Platelet Discriminator
* LD = _______
* UD ________
* Fixed discriminator __________
WBC Discriminator
* LD = 30-60 fL
* UD = fixed at 300 fL
RBC Discriminator
* LD = 25-75 fL
* UD = 200-250 fL
Platelet Discriminator
* LD = 2-6 fL
* UD 12-30 fL
* Fixed discriminator 12 fL
162
T o e n s u r e r e a d i n g s f r o m a n in s t r u m e n t
a r e c o n s i s t e n t w i t h o t h e r
m e a s u r e m e n t s
C A L I B R A T I O N
163
T o d e t e r m i n e a c c u r a c y o f t h e
i n s t r u m e n t r e a d i n g s
C A L I B R A T I O N
164
T o e s t a b l i s h r e l i a b i l i t y o f t h e
in s t r u m e n t
C A L I B R A T I O N
165
➟Determines the accuracy and precision of
the analyzers
➟“Tuning” of the instrument
➟Done:
➟Upon installation of machine
➟Every _______ moths
➟Periodic after major repair
C A L I B R A T I O N
166
when haptoglobin is depleted
-haemopexin is low or absent
-plasma methaemalbumin is elevated
* Severe intravascular hemolysis:
167
-although haptoglobin is likely to be reduced or absent
- haemopexin may be normal or only slightly lowered
* Less severe hemolysis
168
Damaging effects of
Heme are limited in 2
ways:
1. By BINDING
2. By DEGRADATION
169
RBC destruction that takes place in the mononuclear phagocytic system _______, _______, _________
spleen, liver, lymph nodes)
170
_____________is very efficient in this respect and followed by the liver
Spleen
171
_______________in hemolytic anemia (disease)
* Splenomegaly
172
* Hallmarks of EH:
1. Phagocytosis of erythrocytes (splenic macrophages or hepatic Kupffer)
2. Cell sequestration
3. Cell removal
173
