haematology Flashcards
1
Q
what is haematology
A
the study of normal and pathological aspects of blood
2
Q
what do haematologists do
A
they diagnose, treat and care for people with blood disorders
3
Q
what are examples of blood disorders
A
bleeding disorders, haemoglobinopathies, haematological malignancies
4
Q
what is the volume of blood in the body
A
5 1/2 litres in a 70kg man (8% of body weight)
females lave 4-5 L whereas males have 5-6 L (due to body size)
5
Q
what can blood be classed as
A
connective tissue
6
Q
what are the physical characteristics of blood
A
sticky, metaillic taste, high O2 levels blood colour is scarlet but if have low O2 levels colour is dark red (not good), pH is 7.35-7.45
7
Q
is bright red blood in the arteries or veins
A
arteries
8
Q
why does the arteries (instead of veins) have bright red blood
A
because higher levels of oxygen are found there
9
Q
what are the functions of blood
A
protection, transportation, regulation
10
Q
describe transport as a function of the blood
A
-it transports O2 and nutrients to body cells.
-transports metabolic waste to lungs and kidneys to eliminate
transports hormones from endocrine organs to target organs
11
Q
describe regulation as a function of the blood
A
- maintains temperature by absorbing and distributing heat (by vasoconstriction and dilation)
- maintains pH by using buffers (acid and base) such as bicarbonate
- maintain normal fluid volume (done by plasma proteins which produce colloid osmotic pressure)
12
Q
describe protection as a function of the blood
A
-prevents excessive blood loss after injury
- prevents infection as have white bc, antibodies and complement proteins
13
Q
how and what is the composition of blood
A
-when take blood out put it in centrifuge
-55% of plasma (least dense)
-1% buffy coat (has leukocytes and platelets)
-45% erythrocytes (most dense)
14
Q
what type of cells are the most abundant in blood
A
-red blood cells (erythrocytes)
-males have more RBC than females
15
Q
what is haematocrit
A
the % of erythrocytes (RBC) in blood
16
Q
what’s the volume of leukocytes in blood
A
1%
16
Q
what is the function of leukocytes
A
-defense against disease
-they can leave capillaries by diapedesis which is when you move through tissue spaces by ameboid motion and positive chemotaxis
17
Q
what is leukocytosis
A
this is when the white BC count is over 11 x10*9 (means you have an infection so response is normal)
18
Q
what are the types of leukocytes (phagocytes)
A
-neutrophils, basophils, eosinophils, monocytes
19
Q
starting from the most to least dense put the leukocytes in order
A
-neutrophils
-lymphocytes
-monocytes
-eosinophils
-basophils
(never let monkeys eat bananas)
20
Q
what is the function of RBC (erythrocytes)
A
-gas transport such as O2 and CO2
-contributes to blood viscosity
-has a 120 life span
21
Q
what are the structural characteristics of RBC (erythrocytes)
A
-biconcave shape (high surface area which allows O2 and CO2 to diffuse quicker)
-anucleate (no nucleus)
-no mitochondria/ ribosomes (no organelles)
22
Q
how do erythrocytes produce energy
A
By the embden meyerhof glycolytic pathway which convers glucose into lactate. And anaerobically produces ATP
23
Q
why do erythrocytes need energy
A
- to maintain shape
24
how and why do erythrocytes need to be flexible
it has a red cell membrane which has spectrin (provides flexibility)
25
why do RBC need flexibility (provided by spectrin)
to change shape
26
what are RBC filled with
97% of haemoglobin (for gas transport)
27
what is the structure of haemoglobin
-binds and carries O2
-globin is a large protein made of 4 polypeptide chains (2 alpha and 2 beta chains)
-RBC has 200-300 million hae (males have more than females)
28
haemoglobin structure
-haem binds to a globin chain (gives red colour)
-haem is made of protoporphyrin ring that's made up of 4 pyrrole rings
- there's iron (gives colour) in the middle which binds to 1 O2
-each hae transports 4 O2
29
what's oxyhaemoglobin
produces ruby red substance
30
what happens when O2 is loading in lungs
-oxyhaemoglobin is produced
-O2 is abundant (lots) in lungs
-hae picks up 4 O2 molecules
31
what happens when O2 is unloading in tissues
-hae releases O2 into tissues
-deoxyhaemoglobin is produced (dark red)
32
what happens to oxygen's affinity when O2 binds to one haem grp
affinity increases
33
what is co-operativity
causes sigmoidal s shape when oxygen binds to haemoglobin. the change in shape makes it easier for next O2 to bind (that's why affinity increases)
34
what type of structure does haemoglobin have
quaternary structure
35
where is iron located
in the middle of each globin subunit (2 beta and 2 alpha)
36
what type of haemoglobin do foetus's have
2 alpha and 2 gamma chains which have higher affinity
37
how much red blood cells do adults produce every second
2.3 million
38
how much red blood cells do adults produce every minute
138 million
39
what type of stem cells does every cell in the blood come from
haematopoietic stem cell
40
where are haematopoietic stem cells located
in the bone marrow
41
what do you call the formation of red cells
erythropoiesis
42
what is the name for the formation of granulocytes and monocytes
myelopoiesis
43
what is the name for the formation of platelets
thrombopoiesis
44
what is bone marrow
bone marrow is the active site, it has great blood supply (important for transportation)
45
what can multipotential haematopoietic stem cells (hemocytoblast) be split into
common lymphoid progenitor and common myeloid progenitor
46
what are examples of common myeloid progenitors
megakaryocyte, erythrocyte, mast cell and myeloblast
47
what is a type of megakaryocyte
thrombocyte
48
how many RBC do we make per day
10 to power of 12
49
where are RBC made (erythropoiesis)
in the bone marrow
50
describe erythropoiesis as a process of making RBC in bone marrow
haematopoietic stem cells turns into multipotent progenitor cell which turns into common myeloid progenitors. this then develops into a normoblast which turns into a reticulocyte (leaves the bone marrow and goes into blood stream). the reticulocyte is an immature blood cell and still has organelles. finally it turns into an erythrocyte
51
describe normoblasts
- a large cell with a dark blue cytoplasm
- has a central nucleus with nucleoli
- when the normoblast develops into an erythrocyte it goes through divisions such as getting smaller, increased haemoglobin and loses RNA and protein synthesis apparatus
52
characteristics of a normoblast
- has DNA, RNA and is found in bone marrow and blood
53
what can happen if we have too many RBC
can lead to tissue hypoxia
54
what does too many RBC increase
blood viscosity
55
what balances RBC production and destruction
- hormonal controls
- enough iron, amino acids, vitamin B
56
what can blood viscosity lead to
blood clots
57
what does the hormone erythropoietin (EPO) act on
early progenitor cells
58
what is erythropoietin
a 30.4kD glycoprotein hormone
59
what does erythropoietin (hormone) do
- stimulates erythropoiesis (production of RBC)
- they are produced in the kidneys (sometimes liver)
- there is always a small amount in the blood to maintain basal rate
60
what are the effects of erythropoietin (hormone)
- it leads to the rapid maturation of marrow cells
- also increases circulating reticulocyte count in 1-2 days
61
what type of people would abuse the use of EPO
athletes but it could have dangerous consequences
62
why do males have higher RBC count
because testosterone stimulates EPO production
63
what stimulates the kidneys to produce erythropoietin
low levels of O2 (hypoxia) in blood
64
what are the causes of hypoxia
- low RBC numbers because of haemorrhage (bleeding)
- not enough haemoglobin per RBC
- low availability of O2 (in the mountains)
65
what are the dietary needs for erythropoiesis
- nutrients such as amino acids, lipids and carbohydrates
- iron which can be available from your diet and 65% of it is in haemoglobin and rest is in spleen, liver, bone marrow
- vitamin B12 and folic acid
66
what is the daily iron cycle
- the same amount of iron that's consumed/absorbed is lost
- iron absorbed and transferrin transports iron around the body
- iron is lost through urine, skin, faeces
67
what is the life span of erythrocytes
100-120 days
68
what happens to the old RBC
they become fragile and the haemoglobin starts to degenerate (breakdown)
69
where are erythrocytes recycled
in the spleen
70
name erythrocyte disorders
- anaemia
- haemorrhagic anaemia
- iron deficiency anaemia
71
what is anaemia
this is when the blood has abnormally low O2 carrying capacity. this means the blood O2 can't support normal metabolism.
72
what is anaemia accompanied by
fatigue, shortness of breath and chills
73
what are the causes of anaemia
blood loss, low RBC production and high RBC destruction
74
what is haemorrhagic anaemia
this is excessive blood loss.
75
what are the types of haemorrhagic anaemia
acute- rapid blood loss like a stab wound which can be treated by blood replacement..
chronic- persistent blood loss like bleeding ulcer
76
what is the normal haematocrit
47% +or- 5% for males and 42% +or- 5% for females
77
what are the normal haemoglobin levels
130-180g for males and 120-160g for females
78
what is pernicious anaemia
disorder where body doesn't use vitamin B12 properly
79
what is the most common cause of anaemia
iron deficiency
80
what is the prevalence (commonness) of iron deficiency anaemia on post menopausal women and adult men
2-5%
81
what is the cause of iron deficiency anaemia
caused by haemorrhagic anaemia and low iron intake or impaired absorption
82
what do the RBC look like when you have iron deficiency anaemia
they are small (microcytic) and pale (hypochromic)
83
what is a treatment for iron deficiency anaemia
iron supplements
84
what is haemolysis anaemia
when the RBC die faster than they're made
85
what's haemolysis anaemia and premature RBC lysis caused by
infections and haemoglobin abnormalities such as sickle cell anaemia
86
what is sickle cell anaemia
this occurs when an amino acid in the beta chain of haemoglobin changes. this leads to a change in the shape of the RBC
87
what's the mechanism called for dealing with bleeding and clotting
haemostasis
88
what is haemostasis
- maintains the fluidity of circulating blood
- limits and stops bleeding by forming a blood clot whilst at the same time maintaining blood flow
- after the wound has healed it removes the blood clot
89
what is involved in haemostasis
blood vessel wall, platelets, coagulation (stick together) factors
89
describe the platelets in haemostasis
- they have no nucleus (anucleate)
- normal levels is 150-400 x 10*9
- if higher than normal levels then thrombocytosis (too many platelets) and if lower than normal levels then thrombocytopenia (too little platelets)
- 1-3 micro meters
- they circulate 7-10 days
90
what is the role of platelets
- for blood clotting which is done by firstly detecting the damaged vessel endothelium, then it accumulates at the vessel injury and finally, blood clotting starts to stop the circulatory leak
91
what stages are platelets used in
all stages
92
what is the primary haemostatic plug
this is platelet to platelet interactions
93
what is the secondary haemostatic plug
this is platelet and coagulation factors interactions
94
what produces platelets
megakaryocytes
95
how many phases are there in platelet production
2 phases
96
what happens in phase 1 of platelet production
megakaryocyte maturation:
- endomitosis occurs which is when DNA is replicated without cell division occurring
- then cytoplasm enlargement (including cytoskeletal proteins and platelet granules)
97
what happens in phase 2 of platelet production
platelet generation:
- the megakaryocytes extend long branches called proplatelets
- organelles and granules are transported to proplatelets
- they are then driven by cytoskeleton
98
what is platelet production stimulated by
thrombopoietin
99
what is released in a healthy blood vessel
- nitric oxide prostacyclin is released which relaxes blood vessels and stops platelet activation
- antithrombotic is released which reduced blood clots
- natural anticoagulants are also produced which also reduces blood clot formation
100
what's released when the blood vessel is damaged
- prothrombotic which promotes blood clotting
- antithrombotic is inhibited
101
what do the platelets stick to when blood clotting
the von willebrand factor and collagen
102
what happens when the platelets stick to vwf and collagen when blood clotting
platelets become activated and start to release granules and aggregate (stick on top of each other)
103
what are the three steps of haemostasis
- vasoconstriction of blood vessels
- platelet plug formation
- coagulation (blood clotting)
104
describe the first step of haemostasis (vasoconstriction)
after the injury (damage to endothelium) chemicals are released from endothelial cells and platelets. then pain reflex (vasoconstriction) occurs.
105
what happens during coagulation
fibrin is produced from fibrinogen (to reinforce) as the platelet plug isn't stable
106
what are the two pathways for haemostasis
extrinsic and intrinsic pathway
107
what are the two mechanisms that limit clot size
-swift removal and dilution of clotting factors and inhibiting the activation of clotting factors
108
what is fibrinolysis
this breaks down clots after healing which starts within 2 days
109
what are the 2 disorders of haemostasis
- thromboembolic disorders (undesirable clot formed)
- bleeding disorders (abnormalities that stop you from forming clots)
110
what are the types of thromboembolic conditions
- thrombus= when there's a clot in a healthy blood vessel which may lead to tissue death as circulation is blocked or may lead to pulmonary embolism
- embolus= when a clot is freely floating in blood
- embolism= is when the embolus blocks a blood vessel (eg, cerebral emboli)
111
what are the risk factors of thromboembolic conditions
atherosclerosis, inflammation
112
give examples of antithrombotic drugs
aspirin, warfarin, heparin (look at slides for how they work)
113
what are types of bleeding disorders
- von Willebrand's disease= most common inherited bleeding D
- thrombocytopenia= deficient number of platelets in blood
- haemophillia (a,b,c)
