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HEMA 1 > Hemoglobin > Flashcards

Hemoglobin Flashcards

1
Q

hemoglobin

A
  • solid compound = heme + globin
  • gives color to the RBCs
  • aids in oxygen transport by adult RBCs
  • occupies 1/3 of the cell
    • remaining 2/3 = water
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2
Q

site of hemoglobin formation

A

Bone marrow

  • in developing red cells
  • formed after 1 week
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3
Q

components of hemoglobin

A

a. protoporphyrin IX
b. Fe2+
c. polypeptide chains
d. 2,3 diphosphoglyceric acid

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4
Q

precursor of heme

A

Protoporphyrin IX

  • initiates heme synthesis
  • 4 molecules required
  • first produced before joining with globin
  • needed for new RBC & Hgb production only; present in the circulation where it monitors the number of RBCs

*N.V. (blood) = 16-60ug/dL

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5
Q

combines with protoporphyrin IX to form the heme

A

Fe2+

- 4 atoms required

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6
Q

polypeptide chains

A
  • globin chains linked with each other forming a polypeptide
  • protein part of the hemoglobin
  • 2 sets required
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7
Q

changes the hemoglobin’s affinity for oxygen

A

2,3 Diphosphoglyceric acid (2,3 DPG)

  • by-product of the Embden-Meyerhof (glycolytic) pathway
  • temporarily located @ the center of hemoglobin
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8
Q

tissue oxygenation

A
  • tissues are given oxygen

- 2,3 DPG regulates oxygen distribution of adult RBCs onto tissues needing it the most

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9
Q

T/F:

↑ plasma 2,3 DPG = ↓ O2 affinity

A

TRUE

- 2,3 DPG GIVES O2 to tissues needing it most

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10
Q

heme synthesis is ______________

A

Enzymatically directed

  • enzymes are initially combined to produce products that give orders to protoporphyrin IX to make heme
  • has a sequence of steps
  • occurs mainly in erythroid precursors
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11
Q

heme

A

protoporphyrin IX + Fe2+

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12
Q

globin chain production

A
  • “globin” = “globe” form

- designation is based on the differences of color & structure

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13
Q

globin chains

A
  • alpha (α)
  • beta (β)
  • gamma (γ)
  • epsilon (ε)
  • delta (δ)
  • zeta (ζ)
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14
Q

phases of protein synthesis

A

a. transcription
b. processing
c. translation
d. transfer

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15
Q

production of mRNA in one of the amino acids

A

Transcription

  • DNA sends a command to mRNA to find 1 amino acid to form the globin after complete preparation of heme
  • DNA makes sure that the new Hgb of new RBCs will have the same Hgb structure as the dead RBCs
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16
Q

T/F:

having different kinds of hemoglobin in RBCs is normal

A

FALSE

  • having different kinds of hemoglobin will cause an adverse effect on the body –> functional ability of the RBCs are affected
  • there should only be 1 kind of hemoglobin for all RBCs
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17
Q

processing

A

formation of the final mRNA processed by (pre)mRNA

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18
Q

mRNA translates the message onto different amino acids

A

Translation

- mRNA leaves the nucleus for a ribosome in the cytoplasm (tRNA)

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19
Q

tRNA collects a specific amino acid from the cytoplasm & carry them to the appropriate site in the ribosome

A

Transfer

- mRNA tells the tRNA the specific amino acid needed from the DNA’s instruction

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20
Q

hemoglobin variants

A
  • different stages during the development of life
  • identified by electrophoresis
  • variants include:
      • embryonic variant
      • fetal Hgb
      • adult Hgb
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21
Q

present in the first 3 months after conception/copulation

A

Embryonic Hgb

  • production: yolk sac
  • existing Hgb in the embryo:
      • Portland (ζ2γ2)
      • Gower I (ζ2ε2)
      • Gower II (α2ε2)
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22
Q

meaning of “2” in α2ε2

A

indicates where one globin chain links to the other

23
Q

copulation

A

when sperm & egg cells meet

24
Q

fetal hemoglobin

A
  • present from 4th month of embryonic development to birth
  • production at birth: liver
  • globins: α2γ2
25
Q

adult hemoglobin

A
  • from 1 year old above
  • types:
      • HbA1 (α2β2)
      • HbA2 (α2δ2)

*types differ in structure only

26
Q

the most common type of adult hemoglobin

A

HbA1

  • aka “HBA”
  • 97% of adult Hgb

HbA2
- 2%(-3%) of adult Hgb

27
Q

location/s of functional hemoglobin

A

a. yolk sac
- embryonic variant

b. liver
- fetal stage

c. bone marrow
- adult stage

28
Q

in the _____________ stage once hemoglobin is incorporated into the cell, it changes color

A

basophilic erythroblast stage (RBC)

- color changes from blue to red

29
Q

T/F:

after RBCs dies, hemoglobin is captured by the macrophages

A

TRUE

- to be transported to the spleen & liver, as well as the bone marrow

30
Q

when hemoglobin is degraded, ___________ & _________ are recycled, while ______________ is excreted

A

IRON & GLOBIN CHAINS are recycled (heme synthesis); BILIVERDIN is excreted

  • macrophage ingests Hgb –> digestion occurs –> Hgb broken down to Fe & biliverdin –> biliverdin converted to bilirubin & Fe used for heme synthesis
  • globin waits for an available heme for combination
31
Q

heme degradation

A

breaking apart of Fe & porphyrin

32
Q

biliverdin

A

by-product of protoporphyrin breakdown

33
Q

after completion of heme synthesis, excess porphyrin is found in the __________

A

mitochondrion

  • porphyrin will be complexed to zinc
  • porphyrin-zinc complex commands bone marrow to stop producing RBCs when a significant amount is obtained
34
Q

excess protoporphyrin not used for heme production

A

Free erythrocyte porphyrin (FEP)

- normal: FEP = remaining Fe

35
Q

↑ FEP, ↓ Fe

A

indicative of IDA & lead (Pb) poisoning
- there is not enough Fe remaining for heme synthesis

*Pb poisoning: Pb affects the enzymatic sequence of heme production; one enzyme is destroyed by Pb –> heme synthesis inhibited

36
Q

heme production remnants normally present

A

ferritin aggregates

- seen after heme synthesis

37
Q

hemoglobin derivatives that are beneficial to the body

A

Physiologic Hgb

a. oxyhemoglobin
- carries O2 around the body

b. reduced hemoglobin
- collects CO2 to be excreted
- reduced from being oxidized by O2

38
Q

hemoglobin readily converted into a series of compounds by acids/alkali, RedOx agents, & heat

A

Non-beneficial Hgb

a. methemoglobin
b. sulfhemoglobin
c. carboxyhemoglobin
d. carboxysulfhemoglobin

39
Q

hemiglobin (Hi)

A

Methemoglobin

  • normal: 1.5% of the total hemoglobin
  • Fe in heme group is Fe3+ –> unable to carry O2 to tissues
40
Q

T/F:

Fe3+ is an absorbing state

A

FALSE

  • Ferric is NOT AN ABSORBING STATE
  • presence of Fe3+ in Hi is due to the bone marrow’s error of placing the wrong state onto the nRBCs
41
Q

effects of increased Hi

A

a. cyanosis
- low oxygen supply in the body

b. functional anemia
- due to low oxygenation

42
Q

T/F:

Hi can be reversible

A

TRUE

- Hi can be reduced back to Hgb by enzymes

43
Q

oxidation of Fe to Fe3+ state by drugs & chemicals containing sulfur

A

Sulfhemoglobin (SHb)

- sulfur penetrates into RBC, resulting in the oxidation of Fe2+ –> Fe3+

44
Q

produced in a person with increased SHb

A

Green hemochrome

- (yellow) sulfur powder + (bluish) color of patient (due to deoxygenation)

45
Q

inclusions observed when sulfur keeps oxidizing the whole cell

A

Heinz bodies

- denatured precipitated hemoglobin

46
Q

hemoglobin which has an affinity for CO2

A

Carboxysulfhemoglobin

  • cannot transport O2 since it prefers to collect CO2
  • CO2 is not excreted –> more dangerous
  • NOT REVERSIBLE; wait for the cells with it to die
47
Q

this hemoglobin derivative binds with CO more than O2

A

Carboxyhemoglobin (HbCO)

  • binds with CO 210x more than O2
  • builds up until typical symptoms appear (CO poisoning)
48
Q

CO

A

Carbon Monoxide

  • the most dangerous gas
  • sources: gasoline, tobacco smoking
  • product of heme degradation to bilirubin
  • “fart” (by-product) of macrophage ingestion
49
Q

T/F:

the presence of 40% HbCO in blood can lead to death

A

FALSE

- MORE THAN 40% HbCO in blood causes death due to ACUTE CO poisoning

50
Q

other effects of (Hb)CO

A

a. chronic CO poisoning

b. hemolytic anemia

51
Q

chronic CO poisoning

A

Prolonged exposure to small amounts of CO

  • normal
  • body is not exposed to CO 24/7 –> body can still replenish new RBCs
52
Q

CO in hemolytic anemia

A

High/increased

  • RBCs do not reach the normal lifespan (120 days)
  • too much Hgb is released –> macrophage ingest free Hgb –> more CO produced by digestion
53
Q

T/F:

Free Hgb can combine with gases if not encased in the RBCs

A

TRUE
- since they are exposed to different gases, free Hgb can eat whatever gases it wants

*when encased in RBCs, Hgb is only limited to O2 & CO2 because of 2,3 DPG

HEMA 1 (12 decks)

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