Red Blood Cells

Question 1

What is polycythaemia?

Answer 1

When there are more RBC than normal

Question 2

What is bone marrow made out

Answer 2

Fibroblasts, macrophages, endothelium and fat cells

Question 3

Name the growth factors that drive red cell maturation

Answer 3

Interleukin 3, erythropoietin, androgens, thyroxine and growth hormones

Question 4

What are reticulocytes?

Answer 4

New red blood cells that contain reticulin (remnants of mRNA) The spleen removes the reticulin in about 1 to 2 days of their life.

Question 5

What type of iron can be absorbed by the body? and where is it transported too?

Answer 5

Ferrous form and it is then transported to the duodenal enterocytes

Question 6

Whats the function of hepcidin?

Answer 6

Regulates iron absorption and how readily accessible it is.

Question 7

Name some methods of iron loss

Answer 7

Menstrual loss, minor trauma, GI tract, blood sampling and tiny amount in urine and skin shedding.

Question 8

How is iron transported?

Answer 8

By transferrin. These transferrin receptors increase when there is an iron deficiency

Question 9

what is ferritin?

Answer 9

An insoluble form of stored iron

Question 10

What occurs when B12/cobalamin is ingested?

Answer 10

The upper bowel has gastric parietal cells which produce an intrinsic factor that binds to B12. It’s then absorbed in terminal ileum and transported on transcobalamin to the liver.

Question 11

Why are B12 and folic acid required for RBC production?

Answer 11

Vitamin B12 is required to change 5 methyl-tetrahyrdofolate into Tetrahyrdofolate (THF). THF is then changed into 5,10 methelene tetrahydrofolate which catalyses the conversion of uridine into thymidine (Needed for the production of DNA)

Question 12

How are erythropoetins (epo) produced and what does it do?

Answer 12

Tissue hypoxia or anaemia, low oxygen concentration and epo producing tumours. It drives erythopoesis (formation of erythrocytes).

Question 13

What is spectrin?

Answer 13

Protein that links into the cell membrane that give the cell resilience which means it can bounce back after been squeezing through capillaries.

Question 14

What does the glycolytic pathway ending in lactate and pyruvate provide energy for?

Answer 14

Maintaining membrane integrity, prevent oxidation of enzymes and Fe++, maintain gradients of K+ and Ca++

Question 15

What is the key function of a red blood cell and can cause Hb to have a higher affinity for O2?

Answer 15

Bind haemoglobin to oxygen molecules at high oxygen tension and release it at low oxygen tension.

Acidosis and increased temp will increase affinity.

Question 16

what helps release oxygen from haemoglobin?

Answer 16

2,3 Diphosphoglycerate. It enters the globin chains releasing oxygen.
2,3 DPG is increased during exercise, anaemia and high altitudes.

Question 17

Where is myoglobin found?

Answer 17

Found in skeletal muscle and stores oxygen for immediate use. Its released when oxygen levels are low.

Question 18

Why is it important to control pH

Answer 18

Enzymes work optimally at physiological pH, cell membranes become leaky in acidosis, neurons become less able to transmit in acidosis and hyperactive in alkalosis.

Question 19

What happens when if there is a high concentration of H+ ions?

Answer 19

They are converted into water to keep the balance. Excess H+ combine with haemoglobin after the loss of oxygen, this means they will have a greater affinity for oxygen.

Question 20

What happens to RBC as they age?

Answer 20

Membrane more rigid so the are unable to bend and flex, making them more likely to rupture. Loss of glycolytic enzymes and neoantigens are exposed to the cell surface.

Question 21

What occurs after RBC are destroyed?

Answer 21

Free haemoglobin is mopped up by haptoglobin and cleared by the liver. Any excess can appear in the urine. The globin chains will be broken into amino acids. Iron bound to transferrin and returned to macrophages. The porphyrin ring will become billirubin and excreted in bile.