7.8.9. Haematology Flashcards
What type of tissue is the Blood
Blood is a fluid connective tissue.
What is the average blood volume
5 decimeters cubed/ 5L
What percentage of our body weight does the Blood comprise?
7 percent
What percentage composition of the blood is plasma
55 percent of the blood is made up of plasma
Describe the percentage compositions of the blood
55 percent plasma
45 percent red blood cells
less than 1 % is White blood cells and platelets
Describe the composition of the blood plasma and its function.
92 percent water
7% plasma proteins - albumin, Globulin, Fibrinogen, regulatory proteins,
1% other solutes including electrolytes, organic nutrients and waste.
f(x) is transport of organic and inorganic ions
State the functions of the blood
Transport of gases, nutrients, waste products, temperature control.
Defense, contains antibodies, white blood cells and clotting factors.
What is the role of platelets
Form a platelet plug, prevent blood loss, and involved in the clotting process.
What is Hematopoiesis
This is the process by which red blood cells are formed.
The Hemocytoblast is what type of cell
A stem cell, that differentiates to produce all blood cells.
What does the Hemocytoblast differentiate into
Common myeloid progenitor
Common lymphoid progenitor
Myeloid cell line produces which cells
Megakaryocytes
Erythrocytes
Mast cells
Myeloblast - which differentiates and produces basophils, neutrophils, Eosinophils and monocytes.
Describe the stages of the cells involved in red blood cell formation and in order of their formation
- Hemocytoblast
- Proerythroblast
- Early erythroblast - ribosome synthesis
- Late erythroblast - haemoglobin synthesis
- Normoblast - Haemoglobin accumulates
- Shape changes and the nucleus shrinks and degenerates.
- Nucleus and organelles are ejected.
- Reticulocyte keep some ribosomes (blue)
- Cell can collapse inward becoming biconcave.
- Erythrocyte
Requirements for Haemoglobin Synthesis
- Iron
- Vitamins B12 & folic acid (B9)
- Intrinsic factor
- Amino acids
Where does erythropoiesis occur?
- Foetus - early in yolk sac, then liver & spleen
○ later in bone marrow - Infant - all bone marrow
- Adult - only red bone marrow (ribs, vertebrae, skull, upper ends of long bones)
Describe RBC structure
- Specific Shape and Size ○ Biconcave - Very strong - Highly flexible and can deform readily. - Red blood cell contents ○ Organelles - lost its organelles as it matured. ○ Haemoglobin - O2 binds - Main function - Lifespan - 120 days
Describe the life cycle of a red blood cell - breakdown and recycling
- After RBC has aged or become damaged, Macrophages in the liver, spleen, lymph nodes break it down.
- Haemoglobin broken down into heme and globin.
- Some components are recycled and some are degraded.
- Heme converted to bilirubin. Which is converted to bilirubin and serum albumin. This is picked up by liver and bilirubin is secreted as bile.
- Bile absorbed by intestine where it is metabolised into urobilinogen. This is excreted as stercobilinogen in the faeces.
- Iron in heme complex is recycled. It is combined with transferrin (transport protein) in the blood. Carried to the spleen for storage, or stored in the liver as ferritin.
- Iron goes back into circulation.
Causes of hypoxia
- Increase in exercise
- High altitude
- Smoking
- Bleeding
Describe Erythrocyte homeostasis
- Low O2 blood level detected in kidneys (stimulus)
- Kidneys increase production of erythropoietin
- In bone marrow, stem cells increase Red Blood Cell Production
- O2 blood level returns to normal
- Stimulus is resolved
At which stage in the pathway does a redblood cell loose its nucleus
During the normoblast stage
What happens if the reticulocyte is released prematurely.
More haemoglobin can be carried.
Is it possible to see reticulocytes during circulation
Yes, it is normal to be able to see up to 2 percent of reticulocyte
Under which situation would you see a lot of reticulocytes in the blood
If a person is anaemic, then lots of reticulocytes are released early to compensate for the loss of haemoglobin. Remember that anaemia is defined as a total hb concentration that is lower than normal range.
Where is intrinsic factor produced and what does it do.
in the stomach. IF attaches to the b12 vitamin
Where does red blood cell prodction occur in the infant
in ALL bone marrow
Where does red blood cell production take place in the Adult
Only in Red bone marrow.
Ribs, Vertebrae, Skull, upper ends of long bones.
Why can’t the red blood cells repair any damage that it may encounter over the course of its lifespan
no nucleus
What is the transport protein for Iron
Transferrin