Constituents of Blood and Haematopoiesis

Question 1

The average adult blood volume is __1____ and is made up of 45% ___2___ and 50% ___3_____

Answer 1

1) 4.5-6l
2) formed elements
3) plasma

Question 2

Describe simply the constituents of blood?

Answer 2

Blood can be split into plasma and formed elements
Formed elements can be divided into red cells, white cells and platelets
white cells can be divided into granulocytes (includes neutrophils, eosinophils and basophils) and agranulocytes (includes lymphocytes and monocytes)

Question 3

Explain what plasma is?

Answer 3

This is a solution that suspends all of the other parts of blood
It is made up of 91.5% water
It acts as a solvent for important proteins, nutrients, electrolytes, gases and other substances essential to life

Question 4

How are the granulocytes named?

Answer 4

granulocytes contain granules that are easily visible on light microscopy
they are named according to their uptake of stains

Question 5

What is another name for neutrophils?

Answer 5

polymorphs

Question 6

Neutrophils are called so because ____1_____ they have a short life in circulation because _____2____ their structure is _____3_____

Answer 6

1) don’t take up much eosin or basic dye
2) they transit to other tissues to phagocytose invaders
3) segmented nucleus

Question 7

When may neutrophils be increased?

Answer 7

body stress e.g. infection, trauma, infarction

Question 8

What is the most common white blood cell?

Answer 8

neutrophils

Question 9

Eosinophils are called so because __1____ they play a role in ____2___ and are often involved in ____3______ their structure is ____4_____

Answer 9

1) take up eosin dye which stains red
2) fighting parasitic infections
3) hypersensitivity reactions
4) bilobed nucleus with red granules

Question 10

Who may eosinophils be increased in?

Answer 10

patients with allergic conditions e.g. asthma, allergic rhinitis

Question 11

Basophils are called so because _____1_____ they are the circulating version of _____2_____ but their ______3_____ they play a role in hypersensitivity reactions, the evidence for this is ____4_____ their structure is ___5____

Answer 11

1) take up basic dyes which stain blue/ purple
2) tissue mast cells
3) role is not entirely clear
4) they have Fc Receptors which bind IgE and their granules contain histamine
5) lots of large deep purple granules that often obscure the nucleus

Question 12

What is the least common white blood cell?

Answer 12

basophils

Question 13

How are the agranulocytes named?

Answer 13

they are named so because they do not contain granules that are easily visible on light microscopy (this does not mean that they don’t contain granules)

Question 14

Monocytes circulate for _____1_____ they are much longer lived than ___2____ their structure is ___3_____

Answer 14

1) a week and enter tissues to become macrophages which phagocytose invaders
2) neutrophils
3) largest blood cells, non-lobulated nucleus which often appears kidney bean shaped

Question 15

Which white blood cell is a precursor to macrophages?

Answer 15

monocytes

Question 16

Lymphocytes are the ___1___ and involved in response to ___2___ their structure is ___3___

Answer 16

1) brains of the immune system
2) response to infection
3) condensed nucleus with rim of cytoplasm

Question 17

Haematopoeisis is _______

Answer 17

the term for production of blood cells

Question 18

The haematopoietic system includes __________

Answer 18

the bone marrow
spleen
liver 
lymph nodes
thymus

Question 19

Blood islands are formed in the yolk sac in the 3rd week gestation and produce ___1____ which migrate to ___2_____ these organs are the ______3_________ from 6 weeks to 7 months gestation when the ___4_____ becomes the main source of blood cells

Answer 19

1) primitive blood cells
2) liver and spleen
3) chief sites of haematopoiesis
4) bone marrow

Question 20

During most of pregnancy what are the chief sites of haematopoiesis in the fetus?

Answer 20

liver and spleen

Question 21

In childhood and adult life the _______ is the only source of blood cells in a normal person

Answer 21

bone marrow

Question 22

Describe how the areas of haematopoiesis change from birth as the child grows?

Answer 22

at birth haematopoiesis is present in the marrow of nearly every bone, as the child grows the active red marrow is replaced by fat (yellow marrow) so that haematopoiesis in the adult is confined to the central skeleton and the proximal ends of long bones, only if demand for blood cells increases and persists does the areas of red marrow extend

Question 23

Pathological processes interfering with normal haematopoiesis may result in resumption of haematopoietic activity in ____1______ which is known as __2____

Answer 23

1) spleen or liver

2) extramedullarly haematopoiesis

Question 24

All blood cells are derived from _________

Answer 24

pluripotent stem cells

Question 25

What 2 key properties do pluripotent stem cells have?

Answer 25

self renewal | proliferation and differentiation into progenitor cells committed to one specific cell line

Question 26

Pluripotenitial stem cells differentiate into mature blood cells through intermediate progenitor cells which ______________

Answer 26

have lost ability to self renew but have high proliferative capacity

Question 27

Progenitor cells can be broadly classed as _________

Answer 27

lymphoid (gives rise to lymphocytes) | myeloid (gives rise to all non-lymphocyte cells)

Question 28

As you move down the haematopoietic tree ________

Answer 28

cells and nucleus becomes smaller, DNA is condensed as genes not needed for a specific cell are switched off

Question 29

What are the largest type of blood cells?

Answer 29

monocytes

Question 30

What is the lifespan of neutrophils?

Answer 30

7-8 hours

Question 31

What are blast cells?

Answer 31

nucleated precursor cells e.g. erythroblasts, lymphoblasts, myeloblasts

Question 32

Megkaryocytes are ____ploid

Answer 32

polyploid

Question 33

What are myelocytes?

Answer 33

nucleated precursor between neutrophils and blasts

Question 34

Define self renewal?

Answer 34

a property of stem cells, lost in descendants

Question 35

Define proliferation?

Answer 35

increase in numbers

Question 36

Define differentiation?

Answer 36

descendants commit to one or more lineages

Question 37

Define maturation?

Answer 37

descendants acquire functional properties and may stop proliferating

Question 38

Define apoptosis?

Answer 38

descendants undergo cell death

Question 39

Cellularity of bone marrow _______ with age

Answer 39

decrease

Question 40

How do you calculate someones estimated bone marrow cellularity?

Answer 40

subtract someone's age from 100 | so someone age 80 has estimated bone marrow cellularity of 20%

Question 41

Where is a bone marrow biopsy taken from in adults?

Answer 41

iliac crest or sternum | because red marrow is only found in the axial skeleton

Question 42

In young children where is a bone marrow biopsy taken from?

Answer 42

tibial shaft | because red marrow is found in more bones

Question 43

Apart from bone marrow biopsy what other techniques can be used to sample marrow?

Answer 43

new technique where marrow can be mobilised into the blood for collection and transplantation

Question 44

Where is the bone marrow located in the bone?

Answer 44

cortical hard bone on outside | bone marrow is in between the spongy bone in the inside

Question 45

How do mature cells reach the circulation from the bone marrow?

Answer 45

there are sinusoids in the bone marrow which are gaps that mature cells can go through where they reach the circulation from the blood network in the bone

Question 46

What is the myeloid: erythroid ratio?

Answer 46

relationship of neutrophils and precursors to proportion of nucleated red cell precursors (ranges from 1.5: 1 to 3.3: 1 and can be changed in certain conditions e.g. haemolysis causing a compensatory response)

Question 47

How can we assess haemopoiesis in non-lymphoid mature cells?

Answer 47

routine (and usually sufficient)- blood count, cell indices and morphology less common- bone marrow examination

Question 48

How can we assess haemopoiesis in mature lymphoid cells?

Answer 48

immunophenotyping- expression of antigens indicating lineage or stage of development is often required cytochemistry - rarely used

Question 49

How can we assess haemopoiesis in progenitor/ stem cells?

Answer 49

cells are morphologically indistinguishable so main method used is immunophenotyping, others include clogenic assays or animal models

Question 50

What is immunophenotyping?

Answer 50

uses specific antibodies to identify cell antigens and cell type- e.g. labelling with fluorescent antibodies