Haematopoiesis, haematology, haemostasis (year 2) Flashcards
(189 cards)
1
Q
define haematopoiesis
A
production of blood cells
2
Q
what tissue type are leucocytes, erythrocytes and platelets produced in?
A
haemopoietic tissue
3
Q
where is the major site of haematopoiesis?
A
bone marrow
4
Q
what blood cell has the longest lifespan?
A
erythrocytes
5
Q
what is the average lifespan of an RBC?
A
1-5 months
6
Q
how long is platelets lifespan?
A
10 days
7
Q
how long do leucocytes live for?
A
hours to years depending on the type
8
Q
what blood cells have the shortest lifespan?
A
neutrophils
9
Q
what is the first thing that is noticed when there is a sudden arrest of haematopoiesis?
A
reduction in neutrophils (neutropenia)
10
Q
where is the best site to collect bone marrow in dogs?
A
head of femur and humerus
11
Q
what cells do all blood elements arise from?
A
stem cells
12
Q
what are the types of stem cells?
A
totipotent
pluripotent
multipotent
unipotent
13
Q
define totipotents
A
stem cells that are present in the embryo and can divide into any cell
14
Q
define pluripotent
A
stem cells found in the blastocyst that can differentiate into almost all cells but not into an embryo
15
Q
define multipotent
A
stem cell found in most tissues that can differentiate into a limited range of cells such as haematopoitic stem cells
16
Q
define unipotent
A
stem cells that can only generate one type of cell
17
Q
what can a multipoint haematopoietic stem cell differentiate into?
A
common myeloid progenerator
common lymphoid progenitor
18
Q
name some cells that the common myeloid progenerator may differentiate into
A
erythrocytes
mast cells
megakaryocytes
myeloblast - basophil, eosinophil, monocyte, neutrophil
19
Q
what can common lymphoid progenitor cells differentiate into?
A
NK cells
lymphocytes
20
Q
what is lymphogenesis?
A
lymphocyte production
21
Q
where does lymphogenesis being?
A
bone marrow
22
Q
where do the later stages of lymphocyte maturation, proliferation and migration occur?
A
lymphoid organs
23
Q
in a steady state in bone marrow which pool is expected to dominate?
A
maturation and storage
24
Q
does granulopoiesis or monocytopoiesis occupy the majority of the haematopoetic tissue?
A
granulopoiesis
25
define granulopoiesis
production of granulocytes such as neutrophils, eosinophils and basophils
26
what is granulopoiesis and monocytopoiesis controlled by?
cytokines - mainly IL3 and growth factors
27
what are the three colony stimulating factors that control granulopoiesis and monocytopoiesis?
granulocyte-macrophage CSF
macrophage CSF
granulocyte CSF
28
what control growth factors and cytokines?
presence of inflammation/infection
activated T lymphocytes
neutrophils providing negative feedback on their production
29
what is the proliferative pool?
early mitotically active with a quarter of all granulocytes
30
what is the maturation pool in granulocytopoiesis?
later stages of granulopoiesis containing banded neutrophils
31
what cell dominated the storage pool of granulocytopoiesis?
segmented neutrophils
32
what is the only stage of neutrophils released from bone marrow?
segmented - presence of banded may be due to problems such as inflammation
33
what might inflammation cause an increase in in the blood?
neutrophils (neutrophilia) because of increased release from storage pool
34
what may very acute/severe inflammation cause to the happen to the neutrophils?
consumption of circulating and stored neutrophils causing neutropenia
35
what drives eosinopoiesis?
mainly IL5
36
what cell type is rare to see in circulation?
basophil and mast cells
37
where do basophils mature?
bone marrow
38
where do mast cells mature?
in the peripheral tissue but are derived from bone marrow
39
what are aged/damaged RBCs removed by?
macrophages
40
what is erythropoiesis mainly controlled by?
erythropoietin
41
what is require for erythropoiesis?
iron, copper, B2, B6, B12
42
do RBCs have the capability to repair themselves?
no they have no organelles
43
what stimulates erythropoietin?
hypoxia due to a decrease in RBCs or increased tissue demand or decreased oxygen availability
44
what organ releases erythropoietin?
kidney
45
how long does erythropoiesis take?
5 days
46
describe the process of erythropoiesis
large blasts divide to become smaller
haemoglobin concentration increases then cell division stops when optimal intracellular haemoglobin concentration is reached
nucleus is extruded
organelles and RNA is lost
47
how long does it take a juvenile erythrocyte to mature in blood?
24 hours
48
why are juvenile erythrocytes blue?
because they still have retained organelles
49
what is thrombopoeisis?
formation of platelets from a progenitor that gives rise to a megakaryocyte
50
how are platelets formed from a megakaryocyte?
fragmentation of megakaryocyte cytoplasm and shedding into blood
51
what mediates thrombopoeisis?
thrombopoietin
52
what organ produces thrombopoietin?
liver - constantly produced
53
what else other than thrombopoietin is able to stimulate thrombopoeisis?
IL6 during inflammation
| iron deficiencies
54
how is thrombopoeisis self-regulated?
platelets lost/destroyed
more thrombopoetin available
increased thrombopoeisis
55
when might thrombocytosis be seen?
during inflammation or iron deficiency
56
what should a full haemogram include?
PCV (microhaematocrit tube) and total protein
blood counts
blood smear evaluation
57
what tube would you ideally collect a sample in for haematology?
EDTA tube
58
what colour top do EDTA tubes have?
purple
59
what must be avoided during sampling processing?
```
inadequate mixing
haemolysed specimens
lipaemic specimens (take fasted)
clotted specimens
platelet clumps
diluted specimens
```
60
what blood counts should a full haemogram include?
```
total haemoglobin content
haematocrit - equivalent to PCV
RBC count
RBC index
reticulocyte count
platelet coint
total leukocyte count
(differential leukocyte counts)
```
61
what are the differential leukocyte counts?
```
neutrophils
lymphocytes
monocytes
eosinophils
basophils
```
62
what is it called in either haemoglobin, haematocrit of RBC count is below the reference intervals?
anaemia
63
what is it called in either haemoglobin, haematocrit of RBC count is above the reference intervals?
erythroctosis
64
what should be taken into account when deciding if an animal is anaemic or has erythrocytosis?
age, hydration, species, , breed
65
what are the three main causes of anaemia?
inadequate production from bone marrow
increased destruction
increased loss
66
what are the two types of blood loss anaemia?
acute or chronic
67
what could cause blood loss anaemia?
haemorrhage - trauma, clotting disorder, bleeding lesion
| blood-sucking parasites
68
blood loss anaemia is a proportional loss of all blood components, what are the two stages?
1 - initial decrease in blood volume
| 2 - activation of mechanism to maintain volaemia, influx of water so dilution of blood
69
what compensates during acute blood loss anaemia?
bone marrow is able to compensate loss by increasing erythropoiesis and red cell mass - normalises in 1-2 weeks
70
what is expected during acute blood loss?
decreased total protein
| evidence of regeneration
71
what may chronic blood loss lead to the depletion of?
iron stores leading to an iron deficiency
72
how long does it take iron deficiency anaemia during chronic bleeding in adults?
at least 1 month of continuous bleeding
73
is chronic blood loss anaemia regenerative our non-regenerative?
either - non-regenerative after depletion of ion stores
74
what are the two classes of haemolysis?
immune mediated
| non immune mediated
75
what may cause non immune mediated haemolytic anaemia?
oxidative damage, intra-erythrocytic parasites, bacteria, viruses, mechanical damage
76
where can haemolysis occur?
extravascular or intravascular
77
what mediates extravascular haemolysis?
macrophages on tissue
78
what occurs if the liver capacity of bilirubin is overwhelmed?
hyperbilirubinaemia
| jaundice
79
what occurs if there is intravascular haemolysis?
haemoglobinuria
| red urine
80
how is anaemia classified based of the haemogram?
degree of severity
regenerative response
erythrocyte index
81
what are the classes of the degree of severity of anaemia based on haemograms?
mild (30-36%)
moderate
severe (less than 18%)
82
what its classified by the erythrocyte index of a haemogram?
microcytic, normocytic, macrocytic
| hypochromic, normochromic
83
what is described by microcytic, normocytic and macrocytic?
size of the RBC
84
what is described by hypochromic and normochromic?
colour of RBC - whether it has the correct haemoglobin concentration
85
why does anaemia need to be classified?
understand the underlying pathophysiological mechanisms
86
if regenerative anaemia is present what is functioning normallY?
bone marrow
87
define regenerative anaemia
decrease oxygen carrying capacity leads to erythropoiesis by bone marrow to release higher number of juvenile RBCs into circulation
88
define non-regenerative anaemia
bone marrow fails to respond to decreased oxygen carrying capacity
89
what types of anaemia is generally regenerative?
blood loss
| haemolysis
90
what types of anaemia is generally non-regenerative?
```
iron deficiency
chronic disease/inflammation
drugs
bone marrow disease
endocrine disorders
pre-regenerative
```
91
how is regeneration assessed?
quantification of young erythrocytes in circulation
| bone marrow examination
92
how do young erythrocytes compared to older ones?
darker as they have more organelles
93
what is MCV in the erythrocyte index?
mean corpuscular volume
| average RBC size
94
what is MCHC in the erythrocyte index?
mean corpuscular Hb concentration
| average haemoglobin concentration of RBCs
95
what is MCH in the erythrocyte index?
mean corpuscular Hb
| average amount if haemoglobin per cell
96
if the MCV is raised what does this mean you have?
macrocytic anaemia
97
what is macrocytic anaemia usually due to?
presence of larger cells which are usually juvenile erythrocytes
98
if macrocytic anaemia usually regenerative or non-regenerative?
regenerative
99
what is reduced MCV known as?
microcytic anaemia
100
what is microcytic anaemia usually due to?
smaller cells due to less haemoglobin due to an iron deficiency
101
is normocytic anaemia usually regenerative or non-regenerative?
usually non-regenerative but can be regenerative
102
is normochromic anaemia usually regenerative or non-regenerative?
non-regenerative but may be regenerative
103
is hypochromic anaemia usually regenerative or non-regenerative?
regenerative as juvenile RBCs have less haemoglobin but can be due to iron deficiency
104
what is raised MCHC (hyperchromic) anaemia due to?
almost always artifactual
105
what are the 5 major leucocytes in circulation?
neutrophil, monocyte, lymphocyte, eosinophil, basophil
106
what leucocytes are involved in the innate immune system?
neutrophil, monocyte
107
what leucocytes are involved in the adaptive immune system?
lymphocytes
108
what leucocytes are involved in defence against parasites and allergy?
eosinophils, basophils
109
what leucocytes are granulocytes?
neutrophil, eosinophil, basophil
110
what is a low leucocyte count called?
leucopenia
111
what is a high leucocyte count called?
leukocytosis
112
what may make the WBC count by an automated machine less accurate?
if the WBCs are clumped in a blood clot
| if there are lot of nucleated RBCs
113
where is not a good area of a blood smear to do a leucocyte count and why?
feathered edge - most will be destroyed
114
how is absolute number calculated from the differential leucocyte count?
% x WBC count
115
what is the term given to a neutrophil count that is above the upper reference limit?
neutrophilia
116
what are two common situations when neutrophilia is seen?
```
inflammation
stress leucogram (stress or steroid administration)
```
117
what is neutrophilia from a stress leucogram usually combined with?
lymphopenia, monocytosis, eosinopenia
118
what is neutropenia?
neutrophil count below the lower reference limit
119
what are two common causes of neutropenia?
severe overwhelming inflammation
| bone marrow disease
120
what may cause bone marrow disease?
toxic insult
neoplasia
parvo and other viruses
immune mediated destruction of precursors
121
what is left shift when describing neutrophil numbers?
increase in the number of juvenile neutrophils
122
what are common causes of left shift neutrophilia?
severe inflammation - bacterial infection, immune mediated disease
123
what is monocytosis?
monocyte count about the upper reference limit
124
what are the common causes of monocytosis?
acute/chronic inflammation, tissue damage, necrosis
stress leucogram
leukaemia (extreme)
125
what is a lymphocyte count above the upper reference limit known as?
lymphocytosis
126
what are the common causes of lymphocytosis?
chronic inflammtion
adrenalin release in cats
leukaemia
127
what is a lymphopenia?
lymphocyte count below the lower reference limit
128
when is a lymphopenia commonly seen?
chronic inflammation
stress leucogram
viral disease
129
what is an eosinophil count above the upper reference limit called?
eosinophilia
130
when may an eosinophilia be seen?
parasitic infection
allergy
hypersensitivity
131
what are platelets?
cytoplasmic fragments of megakaryocytes
132
what are some common causes of thrombocytopenia?
increased destruction
increased consumption
decreased production
redistribution
133
what are two main features haemostasis helps to maintain?
vascular integrity
| blood fluidity
134
define primary haemostasis
this is the formation of a primary platelet plug
135
what is required for primary haemostasis to occur?
vascular endothelial damage
136
what does damage to vascular endothelial lead to the exposure of?
subendothelial collagen
137
what is released that inducing rolling in platelets and leucocytes?
P-selectin
138
what does con Willebrand factor bind to?
collagen and platelets
139
what are the functions of platelets?
```
adhesion
aggregation
secretion
procoagulant surface
clot retraction
```
140
what receptors allow platelets to adhere to endothelium?
GPI
141
what do GPI receptors bind to?
collagen or von Willebrand factor
142
what allows platelet to platelet aggregation?
fibrinogen or von Willebrand factor
143
what substances can platelets release after activation?
```
thromboxan
serotonin
factorV
ADP
ATP
plasminogen
```
144
what produces von Willebrand factor?
endothelial cells
145
what is von Willebrand factor?
large multimeric plasma protein
146
what does von Willebrand factor serve as a carrier of?
factor VIII
147
what needs to happen once the primary platelet plug has formed in small defects?
nothing only primary haemostasis is required
148
what needs to happen to the primary platelet plug has formed in large defects?
the plug requires fibrin stabilisation - secondary haemostasis
149
what is secondary haemostasis?
formation of a definitive clot - coagulation
150
what is soluble fibrinogen converted to?
insoluble fibrin
151
what is the conversion of fibrinogen to fibrin mediated by?
thrombin
152
what substances makes the platelet plug more stable?
fibrin crosslinkage
153
what is thrombin generation initiated and sustained by?
initiated - exposure to subendothelium
| sustained - coagulation cascade
154
what is the coagulation cascade?
series of enzyme activating steps resulting in thrombin and insoluble fibrin formation
155
what is the aim of the coagulation cascade?
form insoluble fibrin
156
what is factor I in the coagulation cascade?
fibrinogen
157
what is factor II in the coagulation cascade?
prothrombin
158
what is factor III in the coagulation cascade?
tissue factor
159
what is factor IV in the coagulation cascade?
free calcium
160
what are the three things that most steps of the coagulation cascade involve?
enzyme
substrate
cofactor
161
what letter can the coagulation cascade be simplified into?
Y
162
what is the long arm of the Y in the coagulation cascade?
intrinsic pathway
163
what is the short arm of the Y in the coagulation cascade?
extrinsic pathway
164
what is the base of the Y in the coagulation cascade?
common pathway
165
what is the extrinsic pathway of the coagulation cascade activated by?
extravascular causes (tissue factor) - things that shouldn't be in circulation but are due to damage of endothelium
166
what factor does tissue factor stimulate?
factor VII
167
what is the intrinsic pathway of the coagulation cascade activated by?
intravascular causes - exposure of damaged endothelium
168
what factor does the intrinsic pathway start with?
XII
169
what are the factors in the intrinsic pathway? (in order of activation)
XII
XI
IX
VIII
170
what is the most important pathway to start coagulation?
extrinsic
171
what is the most important pathway to amplify coagulation?
intrinsic
172
what factor does the common pathway begin with?
factor X
173
what are the factors of the common pathway of the coagulation cascade? (in order)
X
V
II
I
174
what laboratory tests are used to test the intrinsic and common pathway?
PTT
175
what tests are used to test the extrinsic and common pathway?
PT (prothrombin time)
176
what test tests the the fibronogen to fibrin step in the coagulation cascade is functional?
TT (thrombin time)
177
where are most coagulation factors produced?
liver - not von Hillebrand factor
178
what are the non-enzymatic coagulation factors?
III
I
V
VIII
179
what are the vitamin K dependant coagulation factors?
II
VII
IX
X
180
what do vitamin K dependent coagulation factors require for activity?
carboxylation - this enzyme if vitamin K dependent
181
what are the two functions that stop indefinite clotting?
dissolution of clot (fibrinolysis)
| natural anticoagulants
182
what is tertiary haemostasis?
fibrinolysis
183
when does the fibrinolytic pathway begin?
when coagulation starts
184
what is the fibrinolytic pathway mediated by?
plasmin
185
what is activated to form plasmin?
plasminogen
186
what are some examples of natural anticoagulants?
intact enodthelium
antithrombin III
protein C
tissue factor pathway inhibitor
187
what does antithrombin III bind to and inactivate?
thrombin (some other factors as well)
188
where is antithrombin III produced?
liver
189
what is the action of antithrombin III enhanced by?
heparin (from mast cells)
