blood Flashcards
(152 cards)
1
Q
Describe the mechanisms of haemostasis.
A
Haemostasis involves a series of processes that prevent and stop bleeding, including vascular spasm, platelet plug formation, and coagulation cascade activation.
2
Q
Define coagulation in the context of physiology.
A
Coagulation is the process by which blood changes from a liquid to a gel, forming a blood clot to prevent excessive bleeding.
3
Q
How do disorders of haemostasis affect the body?
A
Disorders of haemostasis can lead to excessive bleeding or thrombosis, impacting the body’s ability to maintain normal blood flow and respond to injuries.
4
Q
Explain the inflammatory responses to tissue injury.
A
Inflammatory responses to tissue injury involve a complex biological process that includes the activation of immune cells, release of signaling molecules, and increased blood flow to the affected area to promote healing.
5
Q
Describe the process of haemostasis.
A
Haemostasis is the process of stopping bleeding and keeping blood within the damaged vessel, involving three main steps: vasoconstriction, formation of a platelet plug, and blood coagulation.
6
Q
What are the three main steps involved in haemostasis?
A
The three main steps involved in haemostasis are vasoconstriction, formation of a platelet plug, and blood coagulation.
7
Q
Define vasoconstriction in the context of haemostasis.
A
Vasoconstriction is the constriction of blood vessels that occurs immediately after injury to reduce blood flow and minimize bleeding.
8
Q
How does a platelet plug form during haemostasis?
A
A platelet plug forms through platelet activation and loose platelet aggregation at the site of injury, creating a temporary haemostatic plug.
9
Q
What role does collagen play in the haemostasis process?
A
Collagen is exposed when the wall of a blood vessel is injured, triggering platelet activation and contributing to the formation of a platelet plug.
10
Q
Explain the significance of tissue factor in haemostasis.
A
Tissue factor is a protein that is released upon injury to the blood vessel wall, initiating the coagulation cascade and leading to the formation of a definitive haemostatic plug.
11
Q
What is the role of thrombin in blood coagulation?
A
Thrombin is an enzyme that plays a crucial role in blood coagulation by converting fibrinogen into fibrin, which helps stabilize the platelet plug and form a definitive haemostatic plug.
12
Q
How does a definitive haemostatic plug differ from a temporary haemostatic plug?
A
A definitive haemostatic plug is a stable structure formed by fibrin and platelets that effectively seals the vessel, while a temporary haemostatic plug is primarily composed of aggregated platelets and is less stable.
13
Q
Describe the origin of platelets in the human body.
A
Platelets are produced in the bone marrow from megakaryocytes.
14
Q
How do platelets form from megakaryocytes?
A
Cytoplasmic extensions on the cell surface of megakaryocytes break off to form platelets.
15
Q
Define the characteristics of platelets in terms of their cellular structure.
A
Platelets are anucleate, smaller than red blood cells, and colorless.
16
Q
What organelles are found in the cytoplasm of platelets?
A
The cytoplasm of platelets contains mitochondria and smooth endoplasmic reticulum (SER).
17
Q
Identify the types of granules present in platelets.
A
Platelets contain dense granules, alpha granules, and lysosomal granules.
18
Q
Describe the appearance of activated platelets in a blood smear.
A
Activated platelets show clumping in a blood smear.
19
Q
Describe the role of serotonin in activated platelets.
A
Serotonin (5-HT) acts as a vasoconstrictor and is involved in platelet activation and aggregation.
20
Q
What is the function of Platelet Activating Factor in platelet physiology?
A
Platelet Activating Factor promotes platelet activation and aggregation, converts membrane phospholipids to thromboxane A2, increases capillary permeability, and is involved in inflammation.
21
Q
How does thromboxane A2 affect blood vessels?
A
Thromboxane A2 acts as a vasoconstrictor and increases capillary permeability.
22
Q
Identify the source of ADP in activated platelets.
A
ADP is released from platelet mitochondria during activation.
23
Q
Define the relationship between activated platelets and inflammation.
A
Activated platelets release substances that contribute to inflammation, including thromboxane A2 and Platelet Activating Factor.
24
Q
How do monocytes and neutrophils relate to platelet activation?
A
Monocytes and neutrophils can also produce Platelet Activating Factor, contributing to platelet activation and aggregation.
25
Explain the significance of platelet activation and aggregation.
Platelet activation and aggregation are crucial for hemostasis, helping to form blood clots and prevent excessive bleeding.
26
How do platelets become activated during vessel damage?
Platelets become activated upon exposure to sub-endothelial collagen and fibronectin, leading to the secretion of ADP and the synthesis of 5-HT and TxA2.
26
Describe the role of von Willebrand factor in hemostasis.
Von Willebrand factor is released from Weibel-Palade bodies in endothelial cells and is crucial for platelet adhesion to the damaged vessel wall, facilitating the formation of a temporary hemostatic plug.
27
Define the components involved in the formation of a definitive hemostatic plug.
The definitive hemostatic plug is formed through the aggregation of activated platelets, which involves glycoprotein receptors such as GP IIb/IIIa binding to fibrinogen.
28
What is the significance of vasoconstriction in the hemostatic process?
Vasoconstriction reduces blood flow to the damaged area, helping to minimize blood loss and allowing for the formation of a temporary hemostatic plug.
29
Explain the contact phase in platelet activation.
The contact phase refers to the initial interaction of platelets with exposed collagen and other sub-endothelial components, triggering their activation and subsequent aggregation.
30
How do GP Ib/IX and GP Ia/IIb contribute to platelet function?
GP Ib/IX is involved in platelet adhesion to the vessel wall via von Willebrand factor, while GP Ia/IIb plays a role in platelet aggregation by binding to collagen.
31
What is the role of ADP in platelet activation?
ADP is secreted by activated platelets and acts as a potent aggregator, promoting further platelet activation and recruitment to the site of injury.
32
Describe the process of loose platelet clumping.
Loose platelet clumping occurs as activated platelets aggregate at the site of vessel damage, forming a temporary hemostatic plug that helps to control bleeding.
33
What are Weibel-Palade bodies and their function in hemostasis?
Weibel-Palade bodies are specialized storage granules in endothelial cells that release von Willebrand factor, essential for platelet adhesion during the hemostatic response.
34
How does fibrinogen contribute to the formation of the platelet plug?
Fibrinogen acts as a bridge between activated platelets by binding to GP IIb/IIIa receptors, facilitating platelet aggregation and stabilizing the hemostatic plug.
35
Describe the role of the endothelium in platelet aggregation.
The endothelium releases substances like nitric oxide and prostacyclin (PGI2) that prevent platelets from clumping together under normal conditions.
36
Define the temporary haemostatic plug.
The temporary haemostatic plug is formed by loose platelet aggregation and vasoconstriction at the site of vessel injury.
37
What is the significance of von Willebrand factor in platelet function?
Von Willebrand factor facilitates platelet adhesion to the exposed collagen in damaged vessels by binding to glycoprotein Ib/IX on platelets.
38
How do GP IIb/IIIa receptors contribute to platelet aggregation?
GP IIb/IIIa receptors bind fibrinogen, which links platelets together, forming a definitive haemostatic plug.
39
What substances are synthesized during platelet activation?
During platelet activation, substances such as ADP, serotonin (5-HT), and thromboxane A2 (TxA2) are synthesized.
40
Describe the process of vasoconstriction in relation to haemostasis.
Vasoconstriction occurs at the site of injury, reducing blood flow and helping to minimize blood loss while the haemostatic plug is formed.
41
What is the role of fibrinogen in the formation of a definitive haemostatic plug?
Fibrinogen acts as a bridge between activated platelets through GP IIb/IIIa receptors, stabilizing the platelet aggregation to form a definitive haemostatic plug.
42
Describe the role of exposed collagen in coagulation.
Exposed collagen activates Factor XII, initiating the intrinsic pathway of coagulation.
43
How does Tissue Factor (TF) contribute to the coagulation process?
Tissue Factor (TF) activates Factor VII, which is part of the extrinsic pathway of coagulation.
44
Define the role of calcium (Ca2+) in coagulation.
Calcium (Ca2+) is essential for the extrinsic pathway of coagulation, facilitating various steps in the process.
45
Explain the conversion of fibrinogen in the coagulation process.
Thrombin converts fibrinogen to fibrin polymers, which are crucial for forming a stable blood clot.
46
What happens when the intrinsic and extrinsic pathways of coagulation combine?
The combination of the intrinsic and extrinsic pathways leads to the production of Thrombin.
47
Identify the factors involved in the intrinsic pathway of coagulation.
The intrinsic pathway involves exposed collagen and the activation of Factor XII.
48
Identify the factors involved in the extrinsic pathway of coagulation.
The extrinsic pathway involves exposed Tissue Factor (TF) and the activation of Factor VII.
49
Describe the role of zymogens in the clotting process.
Zymogens are inactive precursors of enzymes, specifically clotting factors like Factor II (prothrombin), VII, IX, and X, which are converted to active serine protease enzymes through binding with Ca2+/platelet phospholipids.
50
Define the significance of vitamin K in clotting factors.
Vitamin K is essential for the synthesis of certain clotting factors, as it provides the necessary residues for their activity.
51
How are zymogens converted to active enzymes in the clotting cascade?
How are zymogens converted to active enzymes in the clotting cascade?
52
What are the roles of Factor V and VIII in the clotting process?
Factor V and VIII serve as precursors in the clotting cascade, aiding in the activation of other clotting factors.
53
Explain the function of thrombin in the clotting process.
Thrombin plays a crucial role in converting zymogens into active cofactors, facilitating the clotting process.
54
List the clotting factors that are classified as zymogens.
The clotting factors classified as zymogens include Factor II (prothrombin), VII, IX, and X.
55
Describe the role of Vitamin K in the coagulation process.
Vitamin K is essential for the synthesis of certain clotting factors that are dependent on it, playing a crucial role in the coagulation cascade.
56
How is prothrombin converted to thrombin?
Prothrombin is converted to thrombin by the prothrombinase complex, which includes Factor Xa, Factor Va, Ca2+ ions, and prothrombin.
57
Define the prothrombinase complex.
The prothrombinase complex is a combination of Factor Xa, Factor Va, Ca2+, and prothrombin that facilitates the conversion of prothrombin to thrombin.
58
What components are required for the formation of the prothrombinase complex?
The prothrombinase complex requires Ca2+, Factor Va, Factor Xa, and prothrombin.
59
How does Factor Xa contribute to the coagulation cascade?
Factor Xa activates prothrombin (Factor II) to thrombin (Factor IIa) as part of the prothrombinase complex.
60
What is the significance of phosphatidylserine (PS) and phosphatidylinositol (PI) in the coagulation process?
Phosphatidylserine (PS) and phosphatidylinositol (PI) on the platelet surface provide a binding site for the prothrombinase complex, facilitating the conversion of prothrombin to thrombin.
61
Describe the activation process of Factor Va.
Factor Va is activated by low concentrations of thrombin and is subsequently cleaved by high concentrations of thrombin.
62
Describe the initial step in the formation of a thrombus.
A platelet plug forms rapidly at the site of injury.
63
Identify the factors involved in converting prothrombin to thrombin.
The conversion of prothrombin to thrombin involves Factor Xa, Factor Va, and Ca2+ ions.
64
How does exposed collagen contribute to thrombus formation?
Exposed collagen activates the intrinsic pathway of coagulation.
65
What role does tissue factor play in thrombus formation?
Tissue factor in exposed sub-endothelial tissues activates the extrinsic pathway.
66
Identify the factors activated by thrombin during thrombus formation.
Thrombin activates platelets, factors VIII, V, XIII, and I.
67
Describe the role of Tissue Factor Pathway Inhibitor (TFPI) in coagulation.
TFPI is a plasma protein that binds to the TF/factor VIIa complex, inhibiting the coagulation process.
67
Explain the function of fibrin in the clotting process.
Fibrin forms a clot by enmeshing platelets and erythrocytes.
68
What is the function of Thrombomodulin in the coagulation process?
Thrombomodulin is an endothelial surface receptor protein that binds thrombin, activating protein C, which then inactivates factor Va and factor VIIIa.
69
Define Antithrombin III and its significance in coagulation.
Antithrombin III is a plasma protein that binds to heparin on the endothelial surface, blocking factors IX, X, XI, XII, Thrombin, and Kallikrein, thus preventing excessive coagulation.
70
How does the complex of protein C and protein S affect coagulation factors?
The complex of protein C and protein S inactivates factor Va and factor VIIIa, which are essential for the coagulation cascade.
71
Explain the interaction between Antithrombin III and heparin.
Antithrombin III binds to heparin on the endothelial surface, enhancing its ability to inhibit various coagulation factors.
72
Identify the components involved in the inhibition of the coagulation cascade by Thrombomodulin.
Thrombomodulin binds thrombin, leading to the activation of protein C, which then complexes with protein S to inactivate factor Va and factor VIIIa.
73
What are the key functions of coagulation inhibitors mentioned in the content?
The key functions include inhibiting the coagulation process through binding to specific factors and complexes, thereby preventing excessive clot formation.
74
Describe the process of fibrinolysis.
Fibrinolysis is the process of clot dissolution where a fibrin clot, which is temporary, is removed by the fibrinolytic system.
75
Define plasminogen and its role in fibrinolysis.
Plasminogen is a plasma protein that is cleaved by tissue plasminogen activator (tPA) to form plasmin, which is essential for the breakdown of fibrin clots.
76
How is plasminogen activated in the body?
Plasminogen is activated by tissue plasminogen activator (tPA), which is secreted by the endothelium and activated by fibrin.
77
What is the function of tissue plasminogen activator (tPA)?
Tissue plasminogen activator (tPA) functions to cleave plasminogen into plasmin, facilitating the dissolution of fibrin clots.
78
Explain the relationship between tPA and fibrin.
.tPA is activated by fibrin, which allows it to cleave plasminogen into plasmin, initiating the process of fibrinolysis.
79
What are soluble fibrin fragments?
Soluble fibrin fragments are the products of fibrin breakdown during the fibrinolysis process, resulting from the action of plasmin on fibrin.
80
Identify the components involved in the fibrinolytic system.
The components involved in the fibrinolytic system include plasminogen, tissue plasminogen activator (tPA), plasmin, and fibrin.
81
Describe the process of blood clotting in relation to intact vessels.
Blood clotting occurs within intact vessels and is activated by factors such as atheroma.
82
Identify potential causes of thrombosis.
Thrombosis can result from hypercoagulability or bacterial infection.
83
Explain the consequences of thrombosis.
Thrombosis can lead to embolism, which may result in conditions such as coronary thrombosis, stroke, pulmonary embolism, and deep vein thrombosis (DVT).
84
Define coronary thrombosis and its significance.
Coronary thrombosis refers to the formation of a blood clot in the coronary arteries, which can lead to a myocardial infarction (heart attack).
85
How does atheroma contribute to blood clotting?
Atheroma can activate the blood clotting process within intact vessels.
86
What is the relationship between thrombosis and embolism?
Thrombosis can lead to embolism, where a blood clot travels and obstructs blood flow in other areas of the body.
87
List some conditions that can arise from thrombosis.
Conditions that can arise from thrombosis include myocardial infarction, stroke, pulmonary embolism, and deep vein thrombosis (DVT).
88
Describe the role of aspirin in the treatment of thrombosis.
Aspirin inhibits the formation of thromboxane A2 (TxA2), which is involved in platelet aggregation, thereby reducing the risk of clot formation.
89
What are anti-platelet drugs used for in thrombosis treatment?
Anti-platelet drugs prevent the aggregation and activation of platelets, which helps to reduce the formation of blood clots.
90
Define anticoagulants and provide examples.
Anticoagulants are medications that prevent blood clotting. Examples include heparin and vitamin K antagonists like warfarin.
91
How do thrombolytic agents function in treating thrombosis?
Thrombolytic agents, such as recombinant tissue plasminogen activator (tPA) and streptokinase, work by dissolving existing blood clots.
92
List the types of drugs used in the treatment of thrombosis.
The types of drugs used include anti-clotting drugs, anti-platelet drugs, anticoagulants, and thrombolytic agents.
93
Explain the mechanism of action of heparin as an anticoagulant.
Heparin works by enhancing the activity of antithrombin III, which inhibits thrombin and factor Xa, leading to reduced clot formation.
94
Identify the function of vitamin K antagonists in anticoagulation therapy.
Vitamin K antagonists, such as warfarin, inhibit the synthesis of vitamin K-dependent clotting factors, thereby preventing blood clot formation.
95
Describe von Willebrand's disease and its symptoms.
Von Willebrand's disease is characterized by abnormal bruising and mucosal bleeding due to a genetic deficiency of von Willebrand factor.
96
Explain the causes of Haemophilia.
Haemophilia is caused by a genetic deficiency of clotting factors, specifically factor VIII in haemophilia A and factor IX in haemophilia B.
97
What are the common symptoms associated with Haemophilia?
Common symptoms of Haemophilia include soft tissue bleeding and bleeding into joints.
98
How does severe liver disease affect coagulation?
Severe liver disease leads to a deficiency of coagulation factors and reduced absorption of vitamin K, impacting the blood's ability to clot.
99
Define the role of von Willebrand factor in the body.
Von Willebrand factor is essential for blood clotting as it helps platelets adhere to the blood vessel wall.
100
Identify the types of Haemophilia and their associated factors.
Haemophilia A is associated with a deficiency of factor VIII, while Haemophilia B is associated with a deficiency of factor IX.
101
Discuss the implications of vitamin K in coagulation.
Vitamin K is crucial for the synthesis of certain clotting factors; its reduced absorption can lead to impaired blood coagulation.
102
Describe the primary purpose of inflammation in the body.
The primary purpose of inflammation is to respond to injury or infection, eliminate pathogens, and repair tissue.
103
Define mediators of inflammation.
Mediators of inflammation are substances that are released during the inflammatory response, which can be cell-derived or plasma-derived, and play a crucial role in the inflammatory process.
104
Identify the plasma-derived mediators of inflammation.
Plasma-derived mediators of inflammation include bradykinin and complement fragments.
105
List some cell-derived mediators of inflammation.
Cell-derived mediators of inflammation include prostaglandins, leukotrienes, histamine, platelet-activating factor, ATP, and serotonin (5-HT).
106
How do neurotransmitters contribute to inflammation?
Neurotransmitters such as substance P and calcitonin gene-related peptide (CGRP) contribute to the inflammatory response by transmitting signals that can enhance inflammation.
107
Explain the role of prostaglandins in inflammation.
Prostaglandins are cell-derived mediators that play a role in promoting inflammation, pain, and fever as part of the body's response to injury or infection.
108
What is the function of histamine in the inflammatory response?
Histamine functions to increase blood flow and permeability of blood vessels, facilitating the movement of immune cells to the site of injury or infection.
109
Describe the role of leukotrienes in inflammation.
Leukotrienes are cell-derived mediators that contribute to inflammation by promoting bronchoconstriction, increasing vascular permeability, and attracting immune cells to the site of inflammation.
110
How does bradykinin affect the inflammatory process?
Bradykinin is a plasma-derived mediator that causes vasodilation and increases vascular permeability, contributing to the inflammatory response.
111
What is the significance of platelet-activating factor in inflammation?
Platelet-activating factor is a cell-derived mediator that plays a significant role in promoting platelet aggregation and enhancing the inflammatory response.
112
Describe the role of bradykinin in tissue injury.
Bradykinin sensitizes sensory nerves, contributing to hyperalgesia and pain response.
113
How does vasodilation affect local blood flow during inflammation?
Vasodilation leads to increased local blood flow, which is a key feature of the inflammatory response.
114
Define hyperalgesia.
Hyperalgesia is an increased sensitivity to pain, often resulting from the sensitization of sensory nerves.
115
What are the components of the inflammation response?
The components include rubor (redness), calor (heat), tumor (swelling), and dolor (pain).
116
Explain the significance of increased vascular permeability in inflammation.
Increased vascular permeability allows for the movement of immune cells and proteins to the site of injury, facilitating the inflammatory response.
117
How do prostaglandins contribute to the pain response?
Prostaglandins sensitize sensory nerves, which enhances the pain response during inflammation.
118
What is the relationship between histamine and vasodilation?
Histamine is a mediator that promotes vasodilation, leading to increased blood flow and redness in inflamed tissues.
119
Identify the sensory nerve stimulants involved in the calor response.
Sensory nerves are stimulated by ATP, prostaglandins (PGs), serotonin (5-HT), and bradykinin during the calor response.
120
What is the role of local blood flow in the inflammatory process?
Increased local blood flow helps deliver immune cells and nutrients to the site of injury, aiding in healing.
121
Describe the effects of increased vascular permeability during inflammation.
Increased vascular permeability allows fluids, proteins, and immune cells to exit the bloodstream and enter the tissue, contributing to swelling and inflammation.
122
Describe the end result of inflammation in tissue repair.
The end result of inflammation in tissue repair includes increased blood flow, vascular permeability, and the presence of chemoattractants that bring in leukocytes.
123
How do leukocytes contribute to tissue repair?
Leukocytes contribute to tissue repair by being attracted to the site of inflammation, where they help to clear debris and facilitate the healing process.
124
Define the role of fibroblasts in tissue repair.
Fibroblasts are stimulated to proliferate during tissue repair, leading to the production of extracellular matrix, which forms the scar tissue.
125
What is the significance of increased vascular permeability during inflammation?
Increased vascular permeability allows for the movement of leukocytes and proteins from the bloodstream to the site of injury, aiding in the inflammatory response and tissue repair.
126
How do muscle and epithelial cells respond during tissue repair?
Muscle and epithelial cells are stimulated to proliferate during tissue repair, contributing to the regeneration of tissues.
127
Explain the relationship between inflammation and scar formation.
Inflammation leads to the proliferation of fibroblasts and the production of extracellular matrix, which ultimately results in scar formation.
128
What are chemoattractants and their role in tissue repair?
Chemoattractants are substances that attract leukocytes to the site of inflammation, playing a crucial role in the immune response and tissue repair process.
129
Define platelets and their origin.
Platelets are anucleate cells produced from megakaryocytes and contain granules for activation and aggregation.
130
How is platelet plug formation triggered?
Platelet plug formation is triggered by collagen and tissue factor, leading to the release of ADP, serotonin, and thromboxane A2.
131
Explain the coagulation cascade.
The coagulation cascade consists of intrinsic and extrinsic pathways that converge to produce thrombin, which converts fibrinogen to fibrin for clot stabilization.
132
What is fibrinolysis?
Fibrinolysis is the breakdown of clots via plasmin, which is activated from plasminogen by tissue plasminogen activator (tPA).
133
Identify some disorders of haemostasis.
Disorders of haemostasis include thrombosis, inherited disorders like von Willebrand’s disease and haemophilia, and acquired disorders such as severe liver disease.
134
What are the key components of tissue repair?
Tissue repair involves leukocyte recruitment, fibroblast proliferation, and extracellular matrix formation.
134
Describe the inflammatory response and its mediators.
The inflammatory response involves mediators like bradykinin and prostaglandins, which cause hyperalgesia and pain.
135
Describe the composition of blood.
Blood is composed of 55% plasma, which is a solution of substances in water, and 45% haematocrit cells.
136
Explain the process of haematopoiesis.
Haematopoiesis is the process by which blood cells are formed in the body.
137
Identify common blood pathologies.
Common blood pathologies include conditions such as anemia, leukemia, and clotting disorders.
138
What percentage of blood volume is plasma?
Plasma makes up 55% of blood volume.
139
What percentage of blood volume is made up of haematocrit cells?
Haematocrit cells make up 45% of blood volume.
140
Define plasma in the context of blood composition.
Plasma is the liquid component of blood that contains water and various dissolved substances.
141
How does the composition of blood contribute to its functions?
The composition of blood, including plasma and cells, allows it to transport nutrients, gases, and waste products throughout the body.
142
Describe the composition of plasma.
Plasma is composed of approximately 91% water, 7% proteins, electrolytes, nutrients, waste products, hormones, vitamins, and gases.
143
Define the role of albumins in plasma.
Albumins maintain osmotic pressure, act as buffers, and transport various substances in the plasma.
144
How do globulins function in the plasma?
Globulins play a role in immune response and transport substances in the plasma.
145
What is the significance of fibrinogen in plasma?
Fibrinogen is essential for blood clotting as it is converted into fibrin during the coagulation process.
146
List the components found in plasma proteins.
Plasma proteins include albumins, globulins, enzymes, enzyme precursors, enzyme cofactors, fibrinogen, and antibodies.
147
Explain the importance of electrolytes in plasma.
Electrolytes are crucial for maintaining fluid balance, nerve function, and muscle contraction in the body.
148
Identify the major component of plasma and its percentage.
The major component of plasma is water, which makes up approximately 91% of its composition.
149
