RBC

Question 1

Jobs of the RBC

Answer 1

prevent renal loss
carry carbonic anhydrase
buffer for the blood (like other proteins)

Question 2

what is the role of carbonic anhydrase

Answer 2

allows us to sequester CO2 as bi carbonate

Question 3

biconcave disc allows for

Answer 3

flexible membrane and they can bend on themselves to move through very tight spaces like where capillaries turn; better exchange for gases as well

as well as enhanced surface area

Question 4

RBC amount in body and amt of Hgb carried

Answer 4

5.2 M/100 microliters of blood in men

always near carrying cappacity

14-16 gm of hemoglobin on average

Question 5

production of RBC

Answer 5

begins in yok sac
moves with the incorporation of abdominal contents and then production is taken over by the liver spleen and nodes

finally this moves to the bone marrow in around the 8th or 9th month of life and this is the final placement of the RBC

Question 6

role of glycoproteins

Answer 6

give RBC negative charge and repel from other cells or clumping

Question 7

describe the production of RBC beginning with the stem cell

Answer 7

pluripotent stem cells becomes erythroid progenitor

stops having the potential to turn into other types of cells

the daughter of this progenitor are “committed stem cells”

CFU can be played out from these

Question 8

most important mediator of RBC production

Answer 8

EPO

this is a renal hormone 90% of it comes from the kidney

Question 9

what triggers EPO and what is necessary for this production

Answer 9

Sympathetic response -(bleeding)

need B12 and folic acid for the

DNA synthesis and replication
because these cells are very high turnover they require a lot of this for cell division

Question 10

how does the absence of B12 or folate influence the production of RBC

Answer 10

in the absence of B12 or folate the nucleus foes not keep up with the cytoplasms and doe not do the replication that it needs to

resulting in a large cell

macrocytic anemia

Question 11

pernicious anemia

Answer 11

failure to absorb B 12 leads to pernicious anemia

in order to absorb we need a intrinsic factor that will bind and carry for absorption in the intestine

atrophic stomach
bipass surgery
autoimmune deficiency can destroy intrinsic factor and limit absorption

can lead to pernicious anemia

Question 12

how does EPO influence RBC growth

what happens if EPO does not exist

Answer 12

CFU and common erythropoytin cells that express the EPO receptor

the EPO is a growth factor that stimulates the final differentiation of the stem cells

in the absence of these cells die

Question 13

EPO receptor

how it works when activated

what are JAK and STAT

Answer 13

homodrimeric
formed from two proteins

when bound there is a confirmation change that will stimulate tyrosine kinase molecule activity in cytoplasm

two transcription factors will induce transcription that will lead to the completion of the differentiation process

JAK and STAT are these two factors

Question 14

two lineages that arise from pluripotent stem cell

Answer 14

lymphoid stem cell (only lymphocytes)

myeloid stem cells

can have cancers in both of these lineages

Question 15

erythrocyte is part of what lineage

Answer 15

myeloid stem cell lineage

a lot of steps in between myeloid cell and erythrocyte

Question 16

what is the preerythroblast

where is it located and what role does it play

Answer 16

first cell to make Hgb

confined to the bone marrow

WILL NOT FIND IN BLOOD

will move through stages of development

proerythroblast will force organelles like the nucleus out and the nucleus will become pyknotic

as the Hgb levels increase the cell will get smaller

Question 17

basophil erythroblast

Answer 17

will stain with basic dyes because it is acidic on the inside hence the name
(BLUE)

this is the intermediate in between the proerythrobalst and the reticulocyte

Question 18

reticulocyte

Answer 18

baby RBC

nucleus and protein apparatus/machinery is gone

DOES NOT HAVE A NUCLEUS

contains a few polyribosomes and continues to make protein after nucleus is gone based on mRNA left over

(Hgb levels will continue to rise)

will be able to move into the blood stream and will speak to how aggressively the body is trying to pump out RBC and how much EPO is being produced in response to stress

Question 19

Hgb

Answer 19

speherical tetramer of 4 subunits

pyrroles from succinyl coA and glycine

4 pyrroles form protoporphyrin IX

Addition of iron to protoporhyrin forms Heme

globin polypeptide completes a hemoglobin subunit

(heme plus globin)

which contains iron these are comitted stem cells

Question 20

HgBA

what is it an what is the prophyrin ring

Answer 20

two alpha and two beta subunits (usually a 1:1 combination)

porphyrin ring on which iron binds nitrogen molecules

2 dimers from the tetrame

majority found in most of us

Question 21

which type of iron binds ocygen

Answer 21

ferrous Fe2

Fe3 accumulates and causes oxidative stress

Question 22

methemoglobin

Answer 22

generated by the oxidation of heme to the ferric state causing bluish brown color

high ocygen affinity of methmoglobin means to oxygen is delivered

some globin mutations can stablize iron in this state

you can also get a methemoglobinemia form toxins that oxidize heme orin like nitrate

Question 23

what is the molecule responsible for stabilizing Hgb prior to oxygen binding

Answer 23

oxygen changes to state of the protein

and keeps 2,3, diphosphoglycerate from stabilizing in unbound state

when this occurs DPG can no longer keep oxygen from binding and the 02 affinity increase

Question 24

why are RBC not really cells

Answer 24

no nuclei and no mitochondria
this is why we call them erythrocytes

b/c they would steal the O2 from the tissues

very limited protein repair and membrane maintance is allowed but this is in part of the reason why we see such a short lifespan

Question 25

how does a RBC undergo metabolism

Answer 25

Embden-Myerhof pathway

allows for metabolism
through this glycolytic pathway within the cell

can’t do atp metabolism with oxygen

anaerobic and produces latic acid and 2,3, DPG as biproducts

need glucose form the blood stream and NADH as an essential cofactor

Question 26

what is required for the Embden-Myerhof pathway

Answer 26

need glucose form the blood stream and NADH as an essential cofactor

Question 27

pathophys of SCA

Answer 27

hydrophobic
distortion of the sickle due to a valine substitution for a glutamate hemoglobin leads to mishaping after deoxygenation

allow for aggregation of polymers and sickling

Question 28

how does acidosis and small flow vessels lead to increase intravascular hemolysis with sickle cell anemia

Answer 28

acidosis decreases affinity for oxygen

small low flow vessels

where Hgb has lots of time to dump oxygen

Question 29

low haptoglobin indicates what

Answer 29

intravascular hemolysis because it is gathering HgB

this recycling can lead to an increase in unconjugated bilirubin

jaundice

also see increase in reticulocytes

Question 30

complications of SCA

Answer 30

increased reticulocytes leads to an increase in bone formation

stuck in bones causing dactylitis

bone pain

spleenic infarct

Question 31

oxygen binding influences itself by

Answer 31

a. Loose association of oxygen with hemoglobin molecule

b. Binding of each molecule of oxygen makes hemoglobin more receptive to the next

Question 32

cellular storage form and what it is composed of

Answer 32

i. Ferritin is the storage form of iron in our body = important

Question 33

insoluble form of iron that occurs when ferritin is maxed out

Answer 33

hemosiderin

Question 34

Hypochromic anemia from failure of

Answer 34

transferrin to enter erythroblasts

can’t make chromogen
hypochromic

Can’t make hemoglobin without the iron

Question 35

Apotransferrin in blood binds Fe

Answer 35

form transferrin (very similar to absorption)

this is how iron is transported

Question 36

life span of the RBC and how we use this

Answer 36

i. When we do A1c, we are looking at glucose molecules stuck to the hemoglobin molecules

Question 37

how does the spleen help with the death of RBC

Answer 37

Cells rupture in transit through small spaces, often in the spleen

Spleen is there to recover the old RBCs

many macrophages ingest and return iron to the blood, porphyrin lost as bilirubin