PHYSIOLOGY: Haematopoiesis and haemostasis

Question 1

What makes up blood plasma?

Answer 1

90% water
proteins eg. albumin, immunoglobulins, clotting factors
nutrients
salts

Question 2

What makes up the buffy coat of blood?

Answer 2

white cells and platelets

Question 3

How much of the blood do red blood cells make up?

Answer 3

45%

Question 4

What do plasma proteins do?

Answer 4

balance osmotic pressure between the blood and surrounding tissues
transport lipids and ions

Question 5

What do alpha globulins do?

Answer 5

transport proteins that bind to lipids, fat soluble vitamins and metal ions

Question 6

What does albumin do?

Answer 6

maintains osmotic pressure

Question 7

What is haemopoiesis?

Answer 7

the formation of blood cells

Question 8

What cell is the starting point of haemopoeisis?

Answer 8

haemopoietic stem cell

Question 9

What property does a haemopoietic stem cell have that other blood cells don’t?

Answer 9

can self renew

Question 10

What does a haemopoietic stem cell produce?

Answer 10

progenitor cell

Question 11

What two lineages are produced from haemopoietic progenitor cells?

Answer 11

myeloid and lymphoid

Question 12

What cells have a lymphoid lineage?

Answer 12

B cells
T cells
NK cells
dendrites

Question 13

What does a naive B cell become in the tissues?

Answer 13

plasma cell

Question 14

What is the function of

a) B cell?
b) T cell?
c) NK cell?

Answer 14

a) humoral response
b) cell mediated response
c) anti-viral and anti-tumour

Question 15

What cells have a myeloid lineage?

Answer 15

erythrocytes
platelets
granulocytes
monocytes
dendrites

Question 16

What does a monocyte become in the tissues?

Answer 16

macrophage

Question 17

Give an example of 3 granulocytes and their function

Answer 17

neutrophil - phagocytosis and acute inflammation
basophil - modulate hypersensitivity
eosinophil - destroy parasites and modulate hypersensitivity

Question 18

What is proliferation?

Answer 18

an increase in cell numbers

Question 19

What is differentiation?

Answer 19

descendent commit to one or more lineages

Question 20

What is maturation?

Answer 20

descendants acquire functional properties and may stop proliferating

Question 21

What is apoptosis?

Answer 21

descendants undergo cell death

Question 22

What is the site of haematopoiesis in an embryo?

Answer 22

yolk sac stops week 10
liver begins week 6 (+ spleen)
bone marrow week 16

Question 23

Which type of bone marrow is haemopoietically active?

Answer 23

red

Question 24

In adults, where does haematopoiesis mainly occur?

Answer 24

axial skeleton

bone marrow of skull, ribs, sternum, pelvis, proximal ends of femur.

Question 25

What lineage do dendritic cells have?

Answer 25

myeloid and lymphoid

Question 26

Are immature progenitors or mature cells more common in the bone marrow?

Answer 26

mature cells

Question 27

Give the progression of haematopoiesis that forms an erythrocyte

Answer 27

haemocytoblast proerythroblast early erythroblast late erythroblast reticulocyte mature erthyrocyte

Question 28

What change occurs between an erythoblast and a reticulocyte?

Answer 28

organelles are lost to give biconcave shape

Question 29

What change occurs between reticulocyte to erythrocyte?

Answer 29

cell moves to blood | loses its nucleus + ribosomes

Question 30

Where does platelet production occur?

Answer 30

on the periphery of a megakaryocyte, it buds off

Question 31

How is CO2 carried in the blood?

Answer 31

mostly as bicarbonate (60%) • 10% is dissolved • 30% bound to Hb as carbamino-Hb

Question 32

What is extra medullary haematopoiesis?

Answer 32

occurs out with bone marrow eg. liver, thymus, spleen

Question 33

What is haemostasis?

Answer 33

the arrest of bleeding and maintenance of vascular patency

Question 34

What is primary haemostasis?

Answer 34

the formation of a platelet plug

Question 35

How does endothelial damage attract platelets?

Answer 35

exposes collagen and releases VWF so that platelet adhesion occurs, the platelets then release chemicals to cause platelet aggregation

Question 36

What can cause failure of the platelet plug to form?

Answer 36

vascular causes, reduced no (thrombocytopenia), reduced function or due to VWF

Question 37

What are the signs of failure of the platelet plug to form?

Answer 37

- Spontaneous bruising and purpura - Mucosal bleeding eg epistaxis, GI, conjunctival, menorrhagia - Intracranial haemorrhage - Retinal haemorrhage

Question 38

How can primary haemostasis be investigated?

Answer 38

platelet count

Question 39

What is secondary haemostasis?

Answer 39

the formation of a fibrin clot

Question 40

How is secondary haemostasis triggered?

Answer 40

damage to vessel wall releases clotting factors that convert prothrombin to thrombin, then thrombin converts fibrinogen to fibrin fibrin strands adhere to the platelet plug to form an insoluble clot

Question 41

What usually causes a) single clotting factor deficiency? b) multiple clotting factor deficiency?

Answer 41

a) hereditary eg. haemophilia | b) acquired eg. DIC

Question 42

How does fibrinolysis occur?

Answer 42

tPa converts plasminogen to plasmin which breaks fibrin down into fibrin degradation products

Question 43

How can secondary haemostasis be investigated?

Answer 43

Prothrombin time | Activated partial thromboplastin time

Question 44

Name some naturally occuring anticoagulants

Answer 44

* Serine protease inhibitors | * Protein c and protein s