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Theme 2 - 103 > L1 > Flashcards

L1 Flashcards

1
Q

Oxygen is poorly soluble in plasma. How much more O2 can haemoglobin carry than is directly dissolved in plasma?

A

70x more

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2
Q

How many ATP is formed via anaerobic respiration in rbcs?

A

2 ATP

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3
Q

What percentage of a rbc is Hb?

A

95% dry weight

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4
Q

Each haemoglobin and myoglobin subunit has 1 haem group. Describe the structure of a haem group. (4)

A

porphyrin ring

2D

coloured (because of e- sharing and is NOT due to Fe2+)

bound to ferrous ion (Fe2+)

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5
Q

How many O2 molecules per haem?

A

1

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6
Q

Describe adult/maternal Hb (HbA)

A

2 alpha subunits

2 beta subunits

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7
Q

Describe foetal haemoglobin’s structure and properties (HbF)

A

2 alpha subunits
2 gamma subunits

binds O2 more strongly than adult haemoglobin

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8
Q

Why does an increase in blood CO2 level decrease the affinity of Hb for O2?

A

more CO2 = less O2 in cells -> less muscle contractions -> Hb encouraged to release O2 for muscle contraction

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9
Q

Why does a decrease in blood pH decrease the affinity of Hb for O2?

A

more acidic environment -> damaging to cells -> Hb encouraged to release O2 to raise blood pH to normal level

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10
Q

Give the equation for the formation of carbonic acid

A

H2O + CO2 –> H2CO3

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11
Q

What % of CO2 is:
dissolved?
transported as carbamino?
transported as HCO3-?

A

10%
22%
68%

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12
Q

Explain how CO2 can be transported in the blood as HCO3-

A

CO2 enters and combines with H2O to form H2CO3

this is broken down to H+ and HCO3-

HCO3- then exchanged for Cl- via the band 3 protein (chloride-bicarbonate exchanger)

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13
Q

Explain the chloride shift

A

(Chlorine hates gas)

(at the lungs) O2 enters rbc -> Cl- leaves and enters surrounding blood

(at the muscles) CO2 enters surrounding blood -> Cl- enters rbc

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14
Q

For O2 binding, describe the myoglobin curve and the haemoglobin curve

A

myo: hyperbolic/exponential
haemo: sigmoidal

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15
Q

Describe the effect of 2,3-diphosphopglycerate in HbA vs HbF

A

binds to Hb and lowers its for O2 for HbA but not HbF

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16
Q

Give the dimensions of a rbc in micrometers

A

diameter: 7 micrometers
height: 2 micrometers

17
Q

In terms of the respiratory drive, why is the response to CO2 > than the response to H+ in the blood?

A

the signal in response to H+ in the blood is from the carotid arch

18
Q

What is the mean corpuscular volume (mcv) value?

A

80-100 fL

19
Q

What is the mean cell haemoglobin (mch) value?

A

27-34 per gram

20
Q

What are the Hb values for male and female?

A

male: 13-17 g/dL
female: 12-16 g/dL

21
Q

What are the values for the haemocrit/packed cell volume (pcv) for male and female?

A

male: 40-52%
female: 36-48%

22
Q

Define erythropoiesis and distinguish where it occurs after birth and after age 20.

A

development of rbcs

after birth: bone marrow only

after 20: primarily central bones (eg vertebrae)

23
Q

Where does erythropoiesis occur during embryogenesis? (4)

A

liver
spleen
lymph nodes
yolk sac

24
Q

Describe the steps involved in rbc production from stem cells (4 steps)

hint: 1st step= multipotent stem cells

A

multipotent stem cells ->multipotent myeloid progenitor cells -> lineage-committed progenitor cells -> mature cells

25
Q

What is erythropoietin and state its role.

A

cytokine made in the kidney that drives erythropoiesis

26
Q

What are reticulocytes, how long do they last in the blood and what can they be used to diagnose?

A

precursors to rbcs

2 days

haemolytic anaemia

27
Q

What is methaemoglobinaemia and what causes it?

A

Fe2+ is oxidised to Fe3+ so Hb cannot transport O2

congenital globin mutations (Hb M)
hereditary decrease of NADH
toxic substances

28
Q

Describe what happens in CO poisoning and why is it lethal?

A

Hb cannot transport O2 as CO is bound to its binding site

it is lethal as the PO2 dissolved in blood remains normal so typically undetected until disorientation (as the brain is affected first)

29
Q 
Vitamin B12 and folic acid:
role?
deficiency caused by?
deficiency leads to?
treatment?
A

role in thymidine in DNA formation, important in rbc’s, skin production and gametogenesis

diet, malabsorption, increased utilization, pregnancy

megaloblastic (macrocytic) anaemia

oral folic acid, intramuscular hydroxocobalamin

30
Q

Fe can be stored as ferritin and haemosiderin. Where can Fe be stored?(5)

A 
liver
spleen
erythrocytes
bone marrow
macrophages/monocytes
31
Q

Describe what occurs during polycythaemia

A

affecting all ages, this occurs due to living at high altitudes

rbc count increases and blood viscosity increases

Theme 2 - 103 (3 decks)

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