Haematopoiesis

Question 1

Bone marrow

Answer 1

Haematopoiesis occurs mainly in bone marrow in adulthood
Red marrow - where blood cells develop
Yellow marrow - fat
Neonates - almost all marrow is red

Question 2

Haematopoiesis

Answer 2

Controlled by lineage specific growth factors
Act on a subset of cells to differentiate/ develop/mature cells

Question 3

Haematopoiesis

Answer 3

Pluripotent stem cell (Haematopoietic stem cells) can become non-lymphoid stem cells (also known as colony forming unit (CFU) - granulocyte, erythroid, macrophage (CFU-GEMM))
CFU-GEMM able to differentiate along several cell lines into a unipotent stem cell

Question 4

Myeloid lineage cells

Answer 4

Erythrocyte
Granulocyte - Neutrophil, eosinophil, basophil
Monocyte
Megakarocyte - thrombocyte

Question 5

Eryhtrhoppoiesis

Answer 5

1. Haemocytoblast cell differentiates into a myeloid stem cell
2. Myeloid stem cell undergoes multiple stages of differentiation involving protein synthesis
   Cells fills with Hb, looses organelles and nucleus
   After approx. 4 days reticulocytes are formed
   These remain in the bone marrow for 2 days and are then. released into blood
   After approx. 24 hrs in circulation they loos ribosomes = mature erythrocyte

Question 6

Action of erythropoietin - EPO

Answer 6

Kidneys detect lower oxygen from reduced RBC concentration
Kidney peritubular cells release erythropoietin which acts on early blast cells to proliferate and differentiate into pro erythroblasts

Question 7

EPO

Answer 7

Renal cortex particular cells produce most EPO in the human body
EPO production also occurs in the spleen, liver, bon e marrow, lung

Question 8

White cell production

Answer 8

Myeloid line - will produce all white cells, apart from lymphocytes
Lymphoid line - lymphopoiesis - production of lymphocytes

Question 9

Colony stimulating factors

Answer 9

Differntiation directed by signalling molecules called colony stimulating factors (CSFs) produced by macrophages and T - lymphocytes

Question 10

Action of growth factors like CSF

Answer 10

Stimulate proliferation of early progenitor
Direct differentiation to another cell type
Stimulate cell maturation
Suppress apoptosis

Question 11

Neutrophil

Answer 11

Most numerous white blood cell
Seen in increased numbers during bacterial infection
Responsible for the ingestion of pathogens via phagocytosis

Question 12

Band Cells

Answer 12

Immature neutrophils
Nucleus less lobed

Question 13

Eosinophil

Answer 13

Mature granulocytes that responds to the parastatic infection
Can cause tissue damage in allergic response
Granules contain enzyme that that help fight multicellular parastatic infection

Question 14

Basophil

Answer 14

Responsible for histamine production
Participate in immediate hypersensitive reactions
Role in inflammation

Question 15

Monocyte

Answer 15

C shaped nucleus, large blue - grey cytoplasm - described as ‘ground glass’
Ingests invading organisms defective/ dead self matter

Question 16

Thrombocyte - platelets

Answer 16

Produced in the bone marrow from the fragmentation of cytoplasm of megakaryocytic
Have no nucleus
For a platelet plug in primary haemostasis

Question 17

White cells - Lymphoid

Answer 17

Produced in the bone marrow and they are derived from a pluripotent stem cells which then differentiates to become either a lymphoid stem cell or a non - lymphoid stem cell

Question 18

Lymphocyte

Answer 18

Seen in increased numbers in viral infections
T - cells drive the immune response
B-cells produce antibodies