Blood Flashcards
1
Q
What are the two portions that make up blood
A
- Plasma
- Corpusculated portion (blood cells)
2
Q
Where does hematopoiesis occur in neonates and juveniles
A
The bone marrow of long bones
3
Q
Where does hematopoiesis occur in adults
A
The bone marrow of flat bones and the ends of long bones
4
Q
What are 3 essential components needed for hematopoiesis to occur
A
- Stem cell pool
- Hematopoietic inductive microenvironment
- Hematopoietic cytokines
5
Q
What is the earliest recognizable erythroid precursor
A
Rubriblast
6
Q
Which stage of erythrocyte precursor can no longer undergo division
A
Metarubricyte
7
Q
List 3 changes that occur as erythrocyte precursors mature
A
- Decrease in cell size
- Increasing proportion of the cell occupied by cytoplasm
- Decreased cytoplasmic basophilia
8
Q
Which stage of erythrocyte precursor loses its nucleus
A
Reticulocyte (one stage before a mature RBC)
9
Q
Where is erythropoietin produced
A
By the peritubular interstitial cells of the kidney
10
Q
What physiological trigger causes EPO release
A
Low levels of oxygen in the blood
11
Q
List 3 major functions of EPO
A
- Proliferation of committed erythroid cells
- Increase in hemoglobin synthesis
- Increase erythroid cell maturation rate
12
Q
What are the 3 major functions of erythrocytes
A
- Transport oxygen
- Transport carbon dioxide
- Buffer hydrogen ions
13
Q
What pathway do RBCs use to get most of their energy
A
Embden-Meyerhof pathway (anaerobic)
14
Q
What is the role of NADH in RBC metabolism
A
It maintains iron in a reduced state (Fe2+) and glutathione in a reduced state
15
Q
What are the 2 side pathways of RBC metabolism and what are their functions
A
- DPG shunt (modulate the affinity of hemoglobin for oxygen)
- Pentose phosphate pathway (generates more NADH)
16
Q
What molecule controls the rate of iron absorption
A
Hepcidin
17
Q
How is iron transported in the blood
A
It is bound to transferrin
18
Q
Where is iron stored as ferritin
A
In tissues or plasma
19
Q
Where is iron stored as haemosiderin
A
In tissues only
20
Q
Explain the route that iron takes from the intestine to being incorporated into an RBC
A
Iron goes into the enterocyte and then is absorbed into the blood (rate of which is controlled by hepcidin). In the blood it is bound to transferrin. In red cell precursors, the iron will release from transferrin and incorporate into heme, which will become part of the hemoglobin molecule
21
Q
How many oxygen molecules can be carried on hemoglobin
A
4
22
Q
What can happen as a by-product of oxygen reacting with hemoglobin to make oxyhemoglobin
A
The iron in the hemoglobin can oxidize into the ferric state (Fe3+) and form methemoglobin and free oxygen
23
Q
What is needed for the reaction to revert methemoglobin to function hemoglobin
A
- Cytochrome-b5-reductase
- NADH (from RBC metabolism)
24
Q
Which two forms of oxidative injury to RBCs are irreversible
A
- Oxidative denaturation of Hb to form Heinz bodies
- Oxidative injury to membrane proteins
25
Which form of oxidative injury to RBCs are cats highly susceptible to
Hb oxidative denaturation to form Heinz bodies
26
What is the life span of a RBC in: horses & cows, dogs, and cat
Horses & cows: 150 days
Dogs: 100 days
Cats: 70 days
27
Hb in mammals should be ___ of the total hemoatocrit
1/3
28
What is the term for increased PCV, RBC and Hb, and what is the reason for this to happen
Erythrocytosis
Due to dehydration or increase EPO production
29
What influence does increased reticulocytes have on laboratory diagnostics
Increased MCV and decrease MCHC
30
Where does hematopoiesis occur in fetuses
The liver and spleen
31
How much of the body's iron is stored in hemoglobin
50-70%
32
Describe the sigmoid oxygen dissociation curve
The % saturation of Hb with oxygen plotted against the partial pressure of oxygen (it looks like a hill)
33
What are the 3 classes of granulocytes
1. Neutrophils
2. Eosinophils
3. Basophils
34
What are the 2 classes of mononuclear cells
1. Lymphocytes
2. Monocytes
35
____ have more neutrophils, where as ___ have more lymphocytes
Dogs, cats and horse have more neutrophils
Ruminants and rodents have more lymphocytes
36
What is the role of glutathione (GSH)
Protecting Hb and other red cell components against oxidative injury
37
The majority of lymphocyte production occurs ___, whereas the majority of granulocyte production occurs ___
Lymphocyte: spleen, lymph nodes and GALT
Granulocytes: bone marrow
38
What are the 3 major pools of neutrophils precursors in the bone marrow
1. Mitotic pool
2. Maturation pool
3. Storage pool
39
Dogs, pigs and cats have a __ neutrophil storage pool
Large
40
What are the 2 main storage pools of neutrophils in the blood
1. Marginal (neutrophils adhered to the endothelium)
2. Circulating (neutrophils that are free flowing)
41
In which animal is the marginal: circulating neutrophil pool ratio 3:1
Cats
42
Define "left shift"
When there is an increase in circulating band neutrophils (immature neutrophils)
43
What are 'toxic changes' and what are they represented by
Toxic changes are morphological abnormalities of the cytoplasm of neutrophils
They are represented by:
1. Increased cytoplasmic basophilia
2. Dohle bodies (aggregates of rough ER)
3. Foamy cytoplasm
4. Toxic granules
44
List the causes of neutrophilia
1. Catecholamine mediated stress
2. Corticosteroid induced
3. Inflammation
45
List the causes of neutropenia
1. Acute severe inflammation
2. Endotoxemia
3. Reduced production in bone marrow
4. Increased peripheral destruction
46
Define 'degenerative left shift'
When the absolute number of immature neutrophils exceeds the absolute number of segmented neutrophils
47
Which cause of neutrophilia will also cause a left shift
Inflammation
48
In which species is inflammatory neutropenia more common
Ruminants and horses
49
List the causes of lymphocytosis
1. Catecholamine-mediated stress
2. Age/young animals
3. Chronic inflammation
4. Endocrine disorders
5. Lymphoid neoplasia
50
List the causes of lymphopenia
1. Corticosteroid-induced
2. Acute inflammation
3. Excess loss
4. Congenital/acquired
5. Lymphoma
51
List the causes of monocytosis
1. Inflammation
2. Corticosteroid-mediated
52
List the causes of eosinophilia
1. Hypersensitivity/allergic disorders
2. Parasitism
3. Idiopathic conditions
4. Paraneoplastic syndrome
53
List the causes of eosinopenia
1. Cortico-steroid induced
54
Describe the mechanism of acute severe inflammation neutropenia
The rate of migration of neutrophils into the tissues exceeds the rate at which they can be released from the bone marrow
55
Describe the mechanism of endotoxemia neutropenia
Endotoxins cause a rapid shift of neutrophils from the circulating to marginal pools by promoting adhesion to endothelial cells
56
Describe the mechanism of catecholamine mediated stress neutrophilia
Catecholamines increase blood flow and cause a shift from marginal to circulating pool
57
Describe the mechanism of corticosteroid induced neutrophilia
Increase release of neutrophils from bone marrow stores, cause a shift from marginal to circulating pool and increase life span of neutrophils in the blood
58
Describe the mechanism of inflammatory neutrophilia
Cytokines cause the release of pre-formed neutrophils from the bone marrow and increase production in the bone marrow
59
Describe the appearance of reactive lymphocytes
Larger than a regular lymphocyte with deeply blue (basophilic) cytoplasm and a mature chromatin pattern
60
Describe the mechanism of corticosteroid induced lymphopenia
Increased migration of lymphocytes to lymphoid tissues and decreased efflux from lymph nodes
61
Describe the mechanism of acute inflammatory lymphopenia
Increased migration to inflamed tissues, homing of lymphocytes in lymphoid tissue and decreased movement of lymphocytes from lymph nodes
62
Describe the mechanism of catecholamine mediated stress lymphocytosis
Redistribution of lymphocytes from the spleen, more common in cats and foals
63
Describe the mechanism of chronic inflammatory lymphocytosis
Increased lymphopoiesis in response to chronic antigenic stimulation
64
Which endocrine disorder is most likely to cause lymphocytosis in cats
Hyperthyroidism
65
Which endocrine disorder is most likely to cause lymphocytosis in dogs
Hyperadrenocorticism
66
What can be a result of overactive haemostasis
The formation of thrombi that block blood vessels, resulting in ischaemia
67
Why does hemostasis not occur in steady state conditions
The intact endothelium prevents circulating platelets and clotting factors from interacting with procoagulant proteins in the ECM by synthesizing anticoagulant factors
68
What are the two phases of primary hemostasis
Vascular and platelet phase
69
List 2 anticoagulant factors
Nitric oxide and prostaglandin E2
70
List 3 factors that activate the endothelium to start producing procoagulant facotrs
1. Direct injury
2. Infectious agents
3. Oxidative injury
71
What is the main growth factor that regulates the production of platelets
Thrombopoietin
72
Describe what happens in the vascular phase of primary hemostasis
Following injury to a blood vessel, vasoconstriction by contraction of smooth muscle reduces blood loss
This is cause by neural reflexes and endothelin
73
What is von Willebrand factor
A substance found in plasma and the sub-endothelium that binds platelets, forming a bridge between sub-endothelial collagen and platelet receptors
74
List 2 things that happen to platelets following platelet activation
1. Undergo a shape change (create projections of the cell membrane)
2. Release their granular content (coagulation factors)
75
What stimulates recruitment and aggregation of platelets following platelet activation
ADP and thromboxane A2 (produced by platelets)
76
How does the endothelium restrict the formation of the platelet plug to the site of injury
It secretes NO and PGI2 in response to the substances that platelets release, which inactivate anticoagulant factors
77
Where are coagulation factors produced
The liver
78
Which coagulation factors are vitamin K dependent
Factor II, Factor VII, Factor IX, Factor X
79
Which electrolyte is required for nearly all reactions in the coagulation cascade
Calcium
80
List 2 things that strengthen the platelet plug formed during primary homeostasis
1. Fibrin
2. Contraction of the platelet cytoskeleton
81
What is the final product of the coagulation cascade
Cross-linked fibrin
82
What initiates the coagulation cascade
The exposure of tissue factor, expressed on sub-endothelial cells such as fibroblasts and smooth muscle cells
83
Describe how the intrinsic pathway of coagulation is activated from the extrinsic pathway
The small amount of thrombin generated from the extrinsic pathway amplifies its production by activation factor XI in the intrinsic pathway
84
List the intermediates of the common pathway of the coagulation cascade, from thrombin to cross-linked fibrin
Thrombin -> fibrinogen -> fibrin -> cross-linked fibrin
85
What activates tertiary hemostasis (fibrinolysis)
Tissue plasminogen activator (tPA)
86
What is the role of tissue plasminogen activator
It cleaves plasminogen in the plasma to plasmin so it can cleave fibrinogen and fibrin
87
What helps maintain the dissolution of a platelet plug/thrombus at an appropriate rate
Free plasmin is inactivated by alpha-2 plasmin inhibitor
88
What is the relationship between the kallikrein-kinin system and the coagulation cascade
When factor XII from the intrinsic pathway of coagulation is activated, it converts prekallikrein to kallikrein, which then converts HMWK to bradykinin, causing vasodilation, increased vascular permeability and stimulates an inflammatory response
