Lecture 4

Question 1

How is the Shape of rbcs related to function ?
Do rbcs have nucleus, rna or mitochondria?
how do RBCs make ATP?

Answer 1

Small and flexible - can move through capillaries

• carries oxygen and C02 (flat large surface area)
• no nucleus or rna or mitochondria
• glycolytic pathway - to produce ATP (if have defects in enzyme pathways can get haemolysis)

Question 2

What is Thalassemia

Answer 2

• body makes abnormal form of haemoglobin
• defective globulin chains
• cannot carry as much oxygen
• fatigue, weakness, slow growth, paleness

Question 3

Names of rbc as it goes through erythropoiesis

How many cells are made from 1 pro-normoblast?

Changes in the cell as it forms a mature rbc?

Answer 3

pronormoblast, basophilic normoblast, polychormatic normoblast, pyknotic normoblast, reticulocyte, mature red cell

1 pronormoblast makes 16 red blood cells (7-10 days)
-driven by erythropoetin

changes- increase in amount of haemoglobin (become more red) , chromatin clumping, and loss of rna, nucleus is lost

Question 4

What does Erythropoietin do?

where is it made?

what is the feedback loop for this?

Answer 4

made in kidney, responds to low oxygen - feedback loop with kidney
-stimulates rbc development

Feedback

• kidney senses low oxygen, stimulates erythropoetin to be made, and this goes and drives colony forming units
• and then the reticulocyte goes into the blood and depedning on oxygen delivery to kidney (from rbcs) will either increase or decrease feedback loop

Question 5

What are 5 things that impact oxygen delivery to the kidney

LEARN -could be a good question!? - she said.

Answer 5

• no. of red cells
• amount of oxygen in atmosphere
• oxygen dissociation curve
• some haemoglobins inherited forms - dont dissociate their oxygen redily - high affinity haemoglobins- get erythropotein switched on because the haemoglobin is nt giving the oxygen to the kidney
• poor renal circulation - not getting many rbc through
• low cardiac function

Question 6

effects of erythropoietin

• what receptors does it act through?
• what does it do?

Answer 6

acts through specific epo receptor to increase rbc production (in the bone marrow)

• stimulation throuh BFU-E and CFU-E
• increased haemoglobin synthesis
• reduced rbc maturation time
• increased reticulocyte release

Overall results in increased haemoglobin and therefore increased oxygen delivery

Question 7

When to use erythropoetin

Answer 7

• when patients have renal failure
• when there is anemia of renal failure as not enough erythropotein is being produced to make enough rbcs
• potential for abuse - eg. athletes

Question 8

definitions for
Haematocrit
Haemoglobin

what can affect haemoglobin conc?

Answer 8

Haematocrit - fraction of red blood cells in a volume of blood (is a ratio) (same as packed cell volume)

haemoglobin - measurement taken as concentration of haemoglobin molecules (grams/liter)

haemoglobin conc can be effected by total plasma volume - e.g if a person is dehydrated the reduced plasma volume may mask anaemia or cause polycythemia

Question 9

What does the Reticulocytes count reflect?
what happens when it is increased?

also what happens if there is anaemia and it is low?

Answer 9

normally no nucleated red cells in the blood

• however normal levels 1-2% of reticulocytes
• reticulocyte count rises when there is anemia after increased erythropotein levels,
• will be increased in blood loss ( haemorhage)
• if low reticulocyte count with anemia, then suggests something wrong with bone marrow

Question 10

Things influencing normal reticulocyte response

Answer 10

• Marrow disease
• low iron, folate, b12 deficiencey
• lack erythropotein (renal disease)
• inefficient erythropoesis e.g thalasmemia
• chronic inflammation

Question 11

Breakdown of red blood cells

• where
• where does iron and billirubin go?

Answer 11

-cells are removed in spleen
break down of rbcs, then have release of haemoglobin
-iron is reused , and bilirubin goes into the bile