Fundamentals of Blood and Red Blood Cells Flashcards
(112 cards)
1
Q
What colour is blood plasma?
A
- yellow
2
Q
What % of blood plasma is water?
A
- 92%
3
Q
What distinguishes if a molecule is organic or inorganic?
A
- organic = carbon backbone - inorganic = no carbons
4
Q
What are the main organic compounds?
A
- lipids - carbohydrates - proteins - nucleic acids (DNA/RNA)
5
Q
What are the 2 main purposes of inorganic salts in the blood?
A
- buffer pH - balance osmotic pressure
6
Q
What are the 3 main functions of blood in the body?
A
1 - transport O2, glucose, nutrients and vitamins to tissue 2 - transport proteins, hormones and antibodies 3 - remove CO2 and waste metabolites from tissue
7
Q
Which part of the blood carries proteins?
A
- plasma - P for plasma and P for protein
8
Q
What are the 3 layers in blood following centrifugation?
A
- bottom = RBCs
- middle = WBC and platelets
- top = plasma
9
Q
What are the 3 main cell types in blood?
A
1 - red blood cells 2 - white blood cells 3 - platelets
10
Q
What food do red blood cells resemble?
A
- doughnuts
11
Q
Why does the doughnut shape help O2 saturation?
A
- increases surface area
12
Q
What is haematocrit?
A
- the % of red blood cells relative to the total blood volume
13
Q
Roughly how many white blood cells are in the body in ul?
A
- 5000-10,000ul
14
Q
Roughly how many platelets are in the body in ul?
A
- 250,000 - 400,000ul
15
Q
In addition to increasing surface area, why is the compliant shape of the red blood cells important?
A
- can be squashed - can compress to travel down narrow capillaries
16
Q
What is the normal haematocrit levels in men and women?
A
- women = 42% - men = 46%
17
Q
Roughly how many red blood cells are in the body in men and women in ul?
A
- women = 3.5-5 million ul - men = 4.5-6 million ul
18
Q
Do red blood cells have a nucleus?
A
- no
19
Q
Why do red blood cells not have a nucleus?
A
- no room - aim is to carry O2 - very few organelles
20
Q
What is the average life span of a red blood cell?
A
- 120 days
21
Q
Old red blood cells can rupture, how are these cells removed?
A
- macrophages phagocytose them
22
Q
Roughly what percentage of red blood cells is made up of haemoglobulin?
A
- 25%
23
Q
Red blood cells have an asymmetrical membrane, what does this mean?
A
- the inside and outside of the membrane are different
- intracellularly there is a negative charge
24
Q
What is the main purpose of the negative charge intracellularly in red blood cells?
A
- important for cell signalling
25
What is sceptrin?
- protein inside of red blood cells - forms a mesh like structure as part of the cytoskeleton
26
What does the sceptrin contribute towards in red blood cell appearance?
- the doughnut shape
27
What happens if there is an abnormal level of sceptrin in red blood cells?
- deformities of the red blood cells - normally caused by genetic defects
28
What does the word haematopoiesis mean?
- haema = greek for blood
- poiesis = greek for making something
- making of blood cells
29
What does Erythropoiesis mean?
- eryth = greek for red
- poiesis = greek for making something
- RBC production
30
How are platelets formed?
- start as megakaryoblasts
- differentiate to megakaryocytes
- megakaryocytes produce platelets
31
Where is the site for haematopoiesis, where are all blood cells made?
- in bone marrow - specifically red bone marrow in epiphysis
32
What is the average amount of blood in the body?
- 5L
33
What is the red cell production formula?
- red blood cell volume/lifespan for red blood cell - roughly 1/2 of total blood volume = 2250ml - life span = 120 days - so 2250/120 = 18.75ml blood production/day
34
What is the main hormone that drives early red blood cell development?
- erythopoietin (EPO)
- produced by the kidney
35
Where is erythopoietin (EPO) made?
- in the kidneys
36
Why is erythopoietin (EPO) important in red blood cells?
- red blood cell proliferation - red blood cell maintenance
37
What is a reticulocyte?
- an immature red blood cell
- following enucleation
38
What is enucleation, and what cells does it occur in?
- the removal of the cell nucleus - red blood cells
39
How does enucleation occur?
- red blood cells compress forcing out the nucleus
40
Where do reticulocyte mature?
- in the circulation
41
How long does it take reticulocytes to mature in the circulation?
- 1-3 days
42
What can a high reticulocyte level mean?
- blood loss due to trauma
43
What can a low reticulocyte level mean?
- anemia
- bone marrow is dysfunctional
44
What does haemoglobin mean?
- ha = heme
- eamia = blood
- globulin = spherical protein
45
What protein structure is haemoglobin?
- quaternary stucture
46
How many subunits are haemoglobin, and what are they in adults?
- 4 - 2 x alpha subunits - 2 x beta subunits
47
How are the 4 subunits of haemoglobin held together?
- 4 heme groups hold them together
48
What is fetal haemoglobin?
- haemoglobin in fetus during pregnancy
49
How many subunits are haemoglobin, and what are they in the faetus?
- 4 subunits - 2 identical alpha units - 2 identical gamma units
50
Does adult (HbA) or faetus (HbF) haemoglobin have a higher affinity for O2?
- HbF has a higher affinity
51
HbF has a higher affinity than HbA, why is this important?
- ensure HbF only releases O2 inside the featus
- mum and baby could share blood so featus needs to keep their own O2
52
What is responsible for giving red blood cells their colour?
- heme
53
What is the important part of heme that allows O2 to bind with it?
- iron
54
On a heme molecule with no oxygen, what form does the iron take?
- Fe2+ (ferrous cation)
55
When bound to O2 what form does the iron and O2 take?
- iron = Fe3+ (ferric cation) is oxidised (lose an electron)
- oxygen = O2- reduction (gaining an electron)
- O2 is a now oxidising agent
56
When O2 is bound to iron in the heme, what is the O2- classed as?
- reactive oxygen species - dangerous for tissues
57
How does heme ensure O2-, a reactive oxygen species is not released in this manner?
- it undergoes conformational change - increases the affinity of O2
58
What is the name given to the 4 pyrrole rings that make up heme?
- protoporphyrin
59
What does co-operative binding mean?
- one O2 binds to heme
- heme undergoes conformational changes
- these changes increase the chance other O2 will bind
60
If a heme disassociates from O2, what happens to the other 3 O2 molecules?
- they are more likely to disassociate from the heme
61
If partial pressure of O2 is high does that mean a high or low saturation of O2?
- ⬆️ PO2 = ⬆️ O2 saturation - ⬇️ PO2 = ⬇️ O2 saturation
62
What is allosteric inhibition?
- something is able to bind to a molecule
- not at the active site though
- CO2 binds to different site to O2 on haemoglobulin, but this causes a conformational change
63
What is 2,3 Bisphosphoglyceric (BPG) in red blood cells?
- a molecule present in RBCs
- if tissue is hypoxic RBCs ⬆️ BPG meaning O2 is released where required
64
What is the function of 2,3 Bisphosphoglyceric (BPG) in red blood cells?
- it binds to haemoglobin - ⬇️ affinity of O2, ensuring O2 is released into tissues
65
What does of 2,3 Bisphosphoglyceric (BPG) bind in red blood cells?
- allosteric so not same place as O2 - binds to the centre of the tetramer
66
What is deoxyhemoglobin?
- haemoglobin with no O2 bound
67
What are the 2 ways CO2 be transported in the body?
1 - bind to haemoglobin 2 - diffuse in plasma
68
How many ATP are required for aerobic and anaerobic cellular respiration?
- aerobic = 32 ATP - anaerobic = 2 ATP
69
When partial pressure of O2 is high, what does this do to O2 saturation?
- ⬆️ PO2 = ⬆️ O2 saturation - ⬇️ PO2 = ⬇️ O2 saturation
70
Why is a low partial pressure at tissues, such as muscle a good thing?
- ⬇️ PO2 in muscle = lower affinity for O2 in RBCs
- O2 will therefore be released into the tissues down concentration gradient
71
Why is a high partial pressure inside the lungs a good thing?
- ⬆️ PO2 in lungs mean haemoglobin has high affinity for O2
- PO2 moves down concentration gradient (lungs to blood)
- higher affinity encourages other O2 to bind with haemoglobulin through co-operative binding
72
What is myoglobin?
- iron and O2 binding protein in skeletal muscle
73
What is the structure of myoglobin?
- one alpha helix - one heme group
74
Does myoglobin or haemoglobin have a higher affinity for O2?
- myoglobin
75
Why does myoglobin have a high affinity for O2 and why is it only present in skeletal muscle?
- able to bind with O2 in muscle ⬇️ PO2 in muscle
- ⬇️ PO2 in muscle means O2 flow down gradient into muscle
- myoglobin only releases O2 when O2 is muscle is critically low
76
Does myoglobin have cooperative binding?
- no - only one binding site
77
Does 2,3 Bisphosphoglyceric (BPG) have a higher affinity for HbA or HbF?
- HbA - O2 saturation can occur at ⬇️ PO2 in HbF
78
What are the 2 main ways in which CO2 is able to be transported in the blood?
1 - binding to haemoglobin
2 - changed to bicarbonate by carbonic anhydrase and move in plasma, H+ can then also bind to haemoglobulin
79
If pH is low, which may be the case in working muscles, does haemoglobin have a high or low affinity for O2?
- lower affinity for O2
- higher affinity for CO2
- removing CO2 from blood ⬆️ pH
80
CO2 is an allosteric inhibitor of red blood cells, where does it bind and what does it do to the red blood cells?
- CO2 binds to polypeptide of haemoglobin, terminal amino acid in globulin
- causes conformational change of haemoglobin
- O2 affinity is ⬇️ and O2 is released in to the tissue
81
What enzyme converts CO2 in blood to bicarbonate and hydrogen?
- carbonic anhydrase
82
How does carbonic anhydrase change CO2 into bicarbonate and H+ in the tissues?
- CO2 and H2O are turned into HCO3- and H+ - HCO3- is released into the blood and ⬆️ pH - H+ then binds to haemoglobin
83
Once deoxygenated blood reaches the lungs, how does carbonic anhydrase change bicarbonate in plasma and H+ bound to haemoglobin back into CO2 and H2O in the lungs?
- O2 has a high affinity to haemoglobin
- H+ and CO2 then dissociate from haemoglobin in plasma
- HCO3- and H+ then form CO2 and H20
- CO2 is then released into the lungs to be expired
84
Does O2 or carbon monoxide (CO) have a higher affinity for haemoglobin?
- CO - aprox 200 times stronger binding - able to displace bound O2 through the Bohr effect (allosteric binding)
85
What are some common signs of carbon monoxide poisoning?
- confusion - nausea - lethargy - weakness
86
What is hypovolemia?
- loss of blood fluid or extracellular fluid
87
What can cause hypovolemia?
- blood loss due to trauma - diarrhoea/vomiting - renal failure - use of diuretics
88
What are some symptoms associated with hypovolemia?
- fatigue - headaches - cyanosis - tachycardia - death or shock if not treated
89
What does the term anaemia mean?
- group name for blood disorders - characterised by ⬇️ haemoglobin concentration
90
If there is a ⬇️ in haemoglobin concentration, what does that do to O2 transport?
- ⬇️ O2 transport
91
What can cause anaemia?
- iron deficiency means no iron for O2 to bind with
- blood loss, meaning reducing haemoglubulin
- folate or B12 deficiency
- haemolysis (red blood cell death) means lower haemoglubulin
- autoimmunity, means WBC attach RBCs
92
What are the 2 types of haemoglobinopathies?
1 - effects haemoglobin structure and function 2 - effects quantity of haemoglobin
93
What is an example of a haemoglobinopathy that affects haemoglobin structure and function?
- sickle cell anaemia - single codon mutation changing glutamate to valine
94
Does sickle cell anaemia as an example of haemoglobinopathy affect both oxyhaemoglobulin and deoxyhaemoglobin to the same extent?
- no - deoxyhaemoglobin is affected - forms aggregates causing turbulent flow of blood
95
What are the 2 types of haemoglobinopathy that affects haemoglobin quantity?
1 - a-thalassaemia 2 - B-thalassaemia
96
What causes a-thalassaemia, which is an example of haemoglobinopathies?
- we have 4 alpha genes
- more genes affected = more severe phenotype
- deletion/inactivation of \>3 genes
97
What is Bart syndrome?
- deletion/inactivation of 4 alpha subunit genes
- most severe form of a-thalassaemia
98
What can happen if 3 alpha subunit genes are inactivated/deleted?
- microcytic anaemia
- enlarged spleen/liver
- haemolysis (early red blood cell death)
99
What causes B-thalassaemia, which is an example of haemoglobinopathies?
- normally 2 beta genes are present
- mutations affects B globulins structure and function
- impairs hemoglobin and O2 carrying capacity
100
What can B-thalassaemia, which is an example of haemoglobinopathies cause?
- microcytic anaemia
- haemolysis (early red blood cell death)
- erythroid hyperplasia (abnormal erythrocytes shape)
101
What is aplastic anaemia?
- failure to produce sufficient red blood cells - in red bone marrow
102
What is fanconi anaemia?
- the most common form of aplastic anaemia - poor production of all types of blood cells
103
Is clinical management of anaemic conditions simple?
- no - they are complex and could include a bone marrow transplant
104
What is polycythaemia (also referred to as erythrocytosis)?
- abnormally high level of red blood cells
- blood is therefore thicker than normal
- can cause a ⬇️ in blood volume
105
What is the common cause of polycythaemia?
- mutations of the JAK-STAT intracellular pathway
- abnormal EPO and EPO receptor function
106
How does alterations of JAK-STAT intracellular pathway cause abnormal red blood cell levels?
- JAK-STAT intracellular pathway is involved in cell division - over-activation of the JAK-STAT will cause more red blood cells, similar to how tumour form
107
What symptoms can polycythaemia cause?
- fatigue - dizziness - headaches - bleeding from gums, nosebleeds - can impact upon heart and spleen function - can impair clotting formation
108
How does the partial pressure of O2 affect the affinity of O2?
- ⬆️ PO2 = ⬆️ O2 affinity
- due to co-operative binding
- one O2 binds encourages more O2 to bind
109
CO2 can be increased during metabolism in tissue around the body. This CO2 moves down the concentration gradient from tissues where PCO2 is high into low PCO2 in the the plasma reducing blood pH. CO2 and H+ from carbonic anhydrase reaction can then bind with haemoglobin. What does this do to O2s affinity for haemoglobin?
- ⬇️ affinity of O2 to haemoglobin
- O2 is released into the tissues
110
How can an increase in temperature cause a lower affinity for O2 on haemoglobin?
- ⬆️ temperature affects binding between Fe+ and O2
- ⬆️ temp = ⬇️ affinity
- during exercise temp ⬆️ = offloading of O2 in tissue as needed
111
⬆️ Temperature, ⬇️ pH, ⬆️ BPG and ⬆️ PCO2 can all affect the O2 affinity on haemoglobin. Will this move the disassociation curve to the left or the right and what does than mean in releation to PO2?
- all decrease affinity of O2 to haemoglobulin
- important so O2 released where required
- curve is shifted to the right
- a higher PO2 is required to overcome temperature, pH, BPG and PCO2 and saturate haemoglobin with O2
112
⬇️ Temperature, ⬆️ pH, ⬇️ BPG and ⬇️ PCO2 can all affect the O2 affinity on haemoglobin. Will this move the disassociation curve to the left or the right and what does than mean in releation to PO2?
- all increase O2 affinity to haemoglobulin
- curve is shifted to the left
- a lower PO2 is required to overcome temperature, pH, BPG and PCO2 and saturate haemoglobin with O2
