Haematopoiesis and Anaemia w1

Answer 1

• Has a biconcave disk 7-8 μm diameter, 2μmat thickest point, 1 μm at thinnest
• Lacks most of the organelles
• Has haemoglobin allows transport of O2
• Cytoskeleton and membrane protein support the shape and flexibility to squeeze into capillaries

Question 2

What is hemoglobin?

Answer 2

Hemoglobin is a protein found in red blood cells that carries oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs.

Question 3

What is the structure of hemoglobin?

Answer 3

• Hemoglobin is a tetramer
• made up of four subunits (2 alpha & 2 bata)
• Every subunit is made of 1) a polypeptide chain, 2) a hememolecule, 3) one atom of iron Fe2+ in every heme
• Each subunit contains a heme group, which is a complex of iron and protoporphyrin.
• The heme group is responsible for binding oxygen.

Question 4

What is heme?

Answer 4

Heme is a complex of iron and protoporphyrin. It is found in hemoglobin, myoglobin, and cytochrome enzymes.

Question 5

What is the structure of heme?

Answer 5

Heme is a ring-shaped molecule with an iron atom at the center. The iron atom is coordinated to four nitrogen atoms in the porphyrin ring.

Question 6

What is the difference between hemoglobin and heme?

Answer 6

Hemoglobin is a protein that contains heme. Heme is a complex of iron and protoporphyrin. Hemoglobin is found in red blood cells and carries oxygen and carbon dioxide. Heme is found in hemoglobin, myoglobin, and cytochrome enzymes.

Question 7

Extra on Haemoglobin and Heme

Answer 7

Heme of Hb is produced in the developing RBC precursors

Heme is made by
- Fe2+ = reduced form or Ferrous
- Protoporphyrin IX mojety

ROS, CO, Toxic substances can oxidise Fe2+ into Fe3+ (Ferric state) > Methaemoglobin > cannot transport oxygen > toxic conditions > NADH is needed to revert Methaemoglobin to Haemoglobin.

Developing RBC (Erythroblasts) can synthesize Heme The heme synthesis requires:

1. Enzymes -Y some of them are mutated in some forms of anaemia
2. Co-factors: vitamin 812, vitamin 86 and folate-5 lack will cause anaemia

Question 8

what is hematopoiesis ?

Answer 8

-HSC hematopoiesis is the OG and that’s where blood comes from

• It starts in bone marrow
• Mature blood cells have a short lifespan and must be replaced through a process called hematopoiesis
• HSC is multiopotent – meaning I can differentiate into all types of blood cells within the body
• HSC can have the ability to multiply itself to constantly maintain their number of bone marrow
• HSC is a multi step process - involving several intermediate progenitors, and is regulated by a network of signalling molecules, known as cytokines. These cytokines control the proliferation, differentiation and survival or death of the various progenitors

Question 9

What is the role of erythropoietin (EPO) in hematopoiesis?

Answer 9

• Production of red blood cells aka known as erythropoiesis

-EPO stimulates the production of red blood cells. It is produced by the liver during fetal development and by the kidneys in adulthood.

-EPO levels increase in response to blood loss or low oxygen levels. This helps to compensate for the loss of red blood cells and maintain an adequate supply of oxygen to the body.

EPO during differentiation cells reduce in size > Increase in number > Start making haemoglobin > Lose a nucleus = RBC

Question 10

What is the role of colony-stimulating factors (CSFs) in hematopoiesis?

Answer 10

• CSFs stimulate the production of granulocytes and macrophages. These cells are important for the body’s innate immune response.
• CSF production increases in response to infection. This helps to boost the body’s ability to fight off infection.

Question 11

What is the role of thrombopoietin (TPO) in hematopoiesis?

Answer 11

• TPO stimulates the production of platelets. Platelets are important for blood clotting.

-TPO production is regulated by a negative feedback loop. When platelet levels are low, TPO production increases. When platelet levels are high, TPO production decrease and inhibits production

Question 12

Explain what Granulocytes is and name another type WBC that has the same role?

Answer 12

• Granulocytes are a type of white blood cell that plays a role in defending the body against infection. They include neutrophils, eosinophils, and basophils.
• Macrophages are another type of white blood cell that plays a role in defending the body against infection. They also play a role in removing dead cells and other debris from the body.
• Platelets are small cell fragments that play a role in blood clotting.

Question 13

What are the stages of the red blood cell cycle

Answer 13

1. Proliferation: Hematopoietic stem cells (HSCs) in the bone marrow divide to produce more HSCs and common myeloid progenitors (CMPs).
2. Differentiation: CMPs differentiate into erythroid progenitors, which then differentiate into mature red blood cells.
3. Maturation: Red blood cells lose their nucleus and become filled with hemoglobin.
4. Release: Mature red blood cells are released from the bone marrow and enter the bloodstream.
5. Circulation: Red blood cells circulate in the bloodstream for about 120 days, transporting oxygen to the body’s tissues.

6.Senescence: Red blood cells become old and damaged.

7. Phagocytosis: Old and damaged red blood cells are phagocytosed (eaten) by macrophages in the spleen and liver.The iron from the broken-down red blood cells is recycled to produce new red blood cells.

Question 14

What are the factors that regulate the red blood cell cycle?

Answer 14

• The red blood cell cycle is regulated by a number of factors, including:
• Erythropoietin (EPO): EPO is a hormone that stimulates the production of red blood cells. EPO levels increase in response to low oxygen levels.
• Iron: Iron is an essential component of hemoglobin. Iron deficiency can lead to anemia, a condition in which the body does not have enough red blood cells.
  Vitamins B12 and folate: These vitamins are essential for the production of red blood cells. Deficiency in either vitamin can lead to anemia.

Question 15

What are the disorders that can affect the red blood cell cycle?

Answer 15

Disorders that can affect the red blood cell cycle include:

• Anemia: Anemia is a condition in which the body does not have enough red blood cells or hemoglobin.
• Sickle cell anemia: Sickle cell anemia is a genetic disorder in which the red blood cells are sickle-shaped. Sickle-shaped red blood cells can get stuck in blood vessels, causing pain and other complications.
• Thalassemia: Thalassemia is a group of genetic disorders that affect the production of hemoglobin.
• Leukemia: Leukemia is a cancer of the blood cells, including red blood cells.