Lecture 8 Haemotology 1 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
What is the main component of the blood
Plasma, normal range is about 55 percent
Straw coloured watery liquid. What am I describing
The blood plasma
Describe the composition of the blood plasma
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
What does the common myeloid progenitor differetiate into
M
Myeloid cell line procues 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 Late erythroblast Normoblast Reticulocyte Erythrocyte
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.
State which molecules are needed for Erythropoiesis to occur.
- EPO
- Iron
- Vitamins b12 and folic acid b9
- intrinsic factor
- amino acid
Where is intrinsic factor produced and what does it do.
in the stomach. IF attaches to the b12 vitamin
Where does red blood cell production take place in the fetus
All hametopoeisis takes place in the yolk sac.
Where does red blood cell prodction occur in the infant
RBC production takes place in ALL bone marrow.
Where does red blood cell production take place in the Adult
Adult erythropoiesis can only take place in the RED bone marrow. This is the ribs, vertebrae, skull, upper ends of long bones.
Is it true to say that in terms of duress in an adult, places such as the yolk sac or all bone marrow can be used to produce blood cells?
Yes
What is the rate of erythropoiesis ?
Around 2-3 million red blood cells are produced per second.
How big are the red blood cells
Not sure
State the features of red blood cells
- Highly flexible and deform readily
- no mitochondria, no nucleus.
- 120 day lifespan
State the lifespan of a red blood cell
120 days
Why can’t the red blood cells repair any damage that it may encounter over the course of its lifespan
Because it does not contain a nucleus!!
State the causes of hypoxia
Increase in exercise
High altitude
Smoking
bleeding
What is the transport protein for Iron
transferrin
What happens to damaged aged RBCs
They are broken down by macrophages in the liver, spleen or lymph nodes.
When is Haemoglobin produced
Synthesis begins in the proerythroblast stage
65 % at the erythroblast stage
35 % at the reticulocyte stage.
What does haemoglobin look like
4 subunits,
Where is Iron and transferrin stored
In the spleen
Upon ingestion from a macrophage, what happens to the Haemoglobin in the RBC
1) Hb is broken down into Heme and globin
2) Heme breaks down into bilirubin and iron
3) bilirubin is transported to the liver and secreted into the bile.
4) Iron is transported by transferrin back to the spleen for storage.
Summarize Erythrocyte homeostasis
It is controlled via a negative feedback mechanism.
Low oxygen conc (hypoxia) is the driving force behind producing RBCs.
Hypoxia can be caused by high altitude,smoking,exercise, increase, smoking and bleeding.
What is the driving force behind red blood cell production?
Hypoxic conditions (Low oxygen conc)
Describe the homeostasis feedback loop for Red blood cell production
Low oxygen is the stimulus that is detected
Kidneys respond by increasing EPO production
Stem cells increase RBC production
Oxygen blood levels return to normal.
Describe the structure of Haemoglobin
4 globin subunits 2 alpha subunits 2 beta subunits Globin is a single polypeptide chain Each globin subunit has a Haem group Haem group has an Fe2+ ion. Fe2+ ion binds oxygen irreversibly.
How much oxygen can one Hb molecule transport
One Hb molecule can bind to 4 oxygen molecules.
Megaloblastic anaemia can be detected due to which physical signs
- abnormal enlarged red blood cells
- macryocytic cells give rise to an increased mean cell volume.
What are the causes of Iron deficiency anaemia
it is the most common form of anaemia.
Causes include pregnancy, malnutrition, bleeding from GI tract
State some signs and symptoms of Iron deficiency anaemia.
- Hypochromic RBCs due to loss of color from hb loss
- microcytic cells
- decreased mean cell volume
State the causes of sickle cell anaemia
genetic.
State some signs of sickle cell anaemia
Malformed red blood cell shape, sickle shaped.
Abnormal hb structure
Thalasaemia causes and signs
Genetic,
abnormal hb production.
Define Anaemia, according to WHO defition
Defined as Haemoglobin concentration in whole blood below the accepted normal range.
What constitues a low level of Haemoglobin
- Less than 13.5 g/dl for men
- Less than
State the normal range for Haemoglobin
Approx 15g/dl
12-16g/dl for females
13.5-17.5 g/dl for males.
State the normal range for plasma concentration .
The normal range for plasma concentration is 43-63 %
During which stage of Eryhtocyte formation is the cell commited to its fate
During the Proerythroblast stage
During which stage of Erythrocyte formation is ribosome synthesis
Ribosome synthesis
