14 Haemopoesis

Question 1

What is haemopoesis?

Answer 1

Process of cells getting from bone marrow to blood

Question 2

Haemopoeitic stem cells

Answer 2

In bone marrow
Large bank to fuel cells of blood
Ability to self replicate and differentiate further
Multipotent

Question 3

Common progenitors

Answer 3

Only have ability to differentiate into lineage bound

Question 4

Selection of blood cells

Answer 4

Some undergo apoptosis

250 million erythrocytes formed per day, but this is proportion of overall cells produced

Question 5

RBCs

Answer 5

Life span of 120 days
Degraded by liver/spleen
One RBC contains 1 billion molecules of oxygen
Takes 20 seconds for RBC to circulate body
7 micrometers diameter

Question 6

RBCs structure

Answer 6

Biconcave shape
No nucleus/minimal organelles
No mitochondria to ensure oxygen not used up
Haemoglobin to increase affinity of oxygen binding

Question 7

Erythropoiesis

Answer 7

Erythroblasts start with large nucleus and large amounts of DNA
Gradually nucleus shrinks and removed with most RNA

Question 8

Reticulocytes

Answer 8

Final step before mature erythrocyte
No nucleus
Small amount of RNA to make haemoglobin
Lots of reticulocytes in blood when body recovering from blood loss

Question 9

Erythropoietin

Answer 9

Glycoproteins produced by kidney to increase levels of RBC
Produced by kidneys in response to tissue hypoxia
Acts to stop apoptosis of erythrocyte progenitors
Made in liver when fetus, taken over by kidney around birth

Question 10

Granulocytes

Answer 10

Group of WBCs
Have granules in cytoplasm
Mediate inflammatory reactions in body
Release cytokines, interleukins and leukotrienes
3 types: neutrophils, basophils, eosinophils

Question 11

Neutrophils

Answer 11

First line of defence against bacteria
Multi-lobed nucleus
3 types of granules
Most abundant granulocyte

Question 12

Function of neutrophils

Answer 12

Granules contain lysozomes, matrix metalloproteinases (MMPs) and gelatinase
Phagocytosis
Signalling and antigen presentation
Neutrophil extracellular traps (NETs) - capture pathogens and kill bacteria
Respiratory burst

Question 13

Granulocyte-colony stimulating factor (G-CSF)

Answer 13

Secreted by immune cells and endothelial cells
Released in response to inflammation
Act on bone marrow to increase number of neutrophils
Increases speed at which neutrophils mature

Question 14

Basophils

Answer 14

Release histamine, trigger inflammation
Mediate hypersensitivity reactions 
Bi-lobed nucleus
Purple granules
Granules contain histamine and heparin (blood thinner)

Question 15

Eosinophils

Answer 15

Phagocytose pathogens
Fight parasitic worms
Granules contain antihelminthic proteins and cell component destroying enzymes 
2 nuclear lobes
Spherical granules

Question 16

Granulopoiesis

Answer 16

All 3 lineages go through process of:
Nuclear condensation and lobulation
Formation/increased numbers of granules

Question 17

Monocytes/macrophage

Answer 17

Monocyte in blood, macrophage in tissue
First line of defence
Phagocytose pathogens
Present foreign antigens
Largest of mature blood cells
Unilobular shaped nucleus

Question 18

Platelets (thrombocytes)

Answer 18

Stop belting and mediate haemostasis
Biconvex shape
No nucleus
Lots of protein, ribosomes and clotting factors
Special receptors on surface cause platelet aggregation

Question 19

Thrombopoiesis

Answer 19

Unregulated by thrombopoeitin from liver

Formed from megakaryocyte breaking down

Question 20

What are the 3 types of lymphopoiesis?

Answer 20

B lymphocyte
T lymphocyte
Natural killer cell

Question 21

B lymphocytes

Answer 21

Production of antibodies
B cell specific to specific antigen
Activate T cells
Humoral adaptive immunity
Maturation occurs in bone marrow

Question 22

T lymphocytes

Answer 22

Kill virus infected cells, neoplasticism cells and transplanted tissue
Cell-mediated immunity
Activate B cells to make antibodies
Large nucleus, small rim of cytoplasm
Proliferation and activation caused by IL 2
Microscopically indistinguishable from B cells

Question 23

Migration of T cells

Answer 23

Start in bone marrow or feral liver
Migrate to thymus to mature
Migrate to secondary lymphoid organs

Question 24

Plasma

Answer 24

92% water
8% protein - albumin, clotting factors, hormones,cytokines, antibodies
Contains ions