8 Heamatology

Question 1

What is haematopeoisis

Answer 1

The production of all elements in the blood including RBCs WBCs and platelets

Question 2

What is the composition of blood?

Answer 2

• 55% plasma
• 45% formed elements
• less than 1 % WBCs and platelets

Question 3

What is the constitution of plasma?

Answer 3

• 92% water
• 7% plasma proteins
• 1% other dissolved substances

Question 4

What are the plasma proteins?

Answer 4

Albumin
globulin
regulatory proteins
fibrinogen

Question 5

Function of plasma:

Answer 5

Transport:

• heat
• gases
• nutrients
• waste
• formed elements
• inorganic and organic elements

Question 6

Haematopeisis: lymphocytes

Answer 6

Starts with a haemocytoblast (multipotent stem cell) –> common lymphoid proginetor –> small lymphocyte –> T cell/ Bcell
B call –> plasma cell

common proginetor –> natural killer cell (large granular lymphocyte)

Question 7

Haematopeisis: platelets

Answer 7

haemocytoblast (multi potent cell) –> common myeloid proginetor –> megakaryocte –> thrombocyte

Question 8

Haematopeisis: erythrocyte

Answer 8

Haemocytoblast –> common myeloid proginetor –> mast cell/erythrocyte

Question 9

Haematopoeisis: macrophage

Answer 9

Heamocytoblast –> common myeloid proginetor –> myeloblast –> neutrophil/ basophil/ eosinophil/ monocyte
monocyte –> macrophage

Question 10

Erythropoeisis:

Answer 10

Haemoblastocyte –> proerythroblast (committed cell) –> early/late erythroblast –> nomoblast –> reticulocyte –> erythrocyte

Question 11

Name the phases of erthyropoeisis:

Answer 11

1 ribosomal synthesis - early erthyroblast
2 haemoglobin accumulation - late erythroblast
3 nuclear expulsion - nomoblast

Question 12

Where are RBCs made in adults?

Answer 12

bone marrow –> red bone marrow (skull, ribs, spine) except in emergencies

Question 13

Where are RBCs made in foetuses?

Answer 13

Yolk sac –> liver, spleen –> bone marrow

Question 14

Which phases are most of the haemoglobin made?

Answer 14

65% in the erythroblast phase

35% reticulocyte phase (useful in anaemia)

Question 15

what is a ___blast

Answer 15

a cell which is not yet fully mature

Question 16

How many RBCs do we produce per second?

Answer 16

2-3 million

Question 17

Structure of RBCs

Answer 17

• biconcave disc shape
• very flexible and
• 7-8 micrometers diameter
• 2-3 micrometers width
• no organelles or nucleus so can hold more haemoglobin
• 120 lifespan coz can’t repair themselves
• get less flexy and more fragile as life goes on

Question 18

Where are RBCs broken down

Answer 18

Liver

Question 19

What breaks RBCs down?

Answer 19

Macrophages

Question 20

Explain the process of breaking down RBCs

Answer 20

• macrophage engulfs and separates the contents into
• haem
• globin

Question 21

What happens to haem when RBCs are broken down

Answer 21

• separated into bilirubin which is combined with albumin and taken to the liver where it mixes with bile and can be excreted
• and iron which is transported back to bone marrow in blood combined with transferrin or kept in the liver as ferritin

Question 22

What happens to globin when RBCs are broken down?

Answer 22

It is broken down into amino acids which are used to make more globin or other proteins

Question 23

What happens when we have an excess of bilirubin?

Answer 23

We get jaundis and go yellow.

Question 24

How is the level of RBCs controlled

Answer 24

Homeostasis measuring the amount of O2 in the blood

Question 25

What is a lack of O2 in the blood called

Answer 25

Hypoxemia

Question 26

What is too much O2 in the blood from?

Answer 26

Hypoxia

Question 27

What happens during hypoxemia

Answer 27

The kidneys are stimulated to produce more erythropoeitin

Question 28

Where is erythropoeitin produced?

Answer 28

The kidneys

Question 29

What causes hypoxemia (4)?

Answer 29

smoking (CO competes) blood loss high altitude increase in exercise

Question 30

What are the normal levels of haemoglobin in the blood?

Answer 30

W: 12-16 g/dl M: 13-17 g/dl Av. 15 g/dl

Question 31

How many haemoglobin molecules are there per RBC?

Answer 31

280 million

Question 32

How many molecules of O2 can each haem group hold?

Answer 32

4

Question 33

Structure of haemoglobin:

Answer 33

4 sub units -2 alpha -2 beta each unit consists of a haem molecule bound to a a long polypeptide chain (globin) -Fe2+ ion in the middle -ion can bind with one molecule of oxygen

Question 34

Which gases does haemoglobin carry?

Answer 34

O2 CO2 CO H+

Question 35

Anaemia is classified by:

Answer 35

the below accepted normal levels of haemoglobin in the blood (12-13.5 g/dl)

Question 36

How prevalent is anaemia?

Answer 36

1/3 of the worlds population suffer from it

Question 37

Causes of anaemia:

Answer 37

increased RBC destruction Reduced RBC production Blood loss

Question 38

What happens in iron deficient anaemia:

Answer 38

- microcytic eryhtrocytes form - less mean cell volume - less haemoglobin means paler cells

Question 39

What are the causes of iron deficient anaemia?

Answer 39

anything that puts strain on the body - malnutrition - malabsorption - heavy periods - preganacy

Question 40

What happens in vitamin B12 deficient anaemia?

Answer 40

- Not enough vitamin B12 produces not fully functional RBCs - if lack of intrinsic factor production its called pernicious anaemia - IF allows us to absorb vit B12 form our diet - only treatment is to give an intramuscular injection of vit B12 that bypasses the stomach - Macrocytic RBCs form but they're not full functional

Question 41

Folate deficiency and anaemia:

Answer 41

-very similar to B12 deficiency -also causes macrocytic RBCs causes: -elderly -dietary deficiency -pregnancy

Question 42

Sickle cell anaemia: | where is it prevalent and what happens?

Answer 42

- prevalent in africa and west india - point mutation causes haemoglobin to be transcribed as haemoglobin s - causes sickle shaped cells - get stuck in vessels - no cure - hereditary

Question 43

Thalassaemia: | where is it prevalent and what happens?

Answer 43

Problem with globin chain production causes less RBCs to be made and reduces the blood cells carrying capacity prevalent in Mediterranean and middle/eastern asia