Podcast
Questions and Answers
What is the primary role of vascular spasm in hemostasis?
What is the primary role of vascular spasm in hemostasis?
Which component is crucial for platelet plug formation?
Which component is crucial for platelet plug formation?
What distinguishes the extrinsic pathway of blood clotting from the intrinsic pathway?
What distinguishes the extrinsic pathway of blood clotting from the intrinsic pathway?
What is the function of bradykinin in the hemostatic process?
What is the function of bradykinin in the hemostatic process?
Signup and view all the answers
Which factor is activated first in the intrinsic pathway of blood clotting?
Which factor is activated first in the intrinsic pathway of blood clotting?
Signup and view all the answers
What role does FXa play in the common pathway of coagulation?
What role does FXa play in the common pathway of coagulation?
Signup and view all the answers
What initiates the activation of the extrinsic pathway of coagulation?
What initiates the activation of the extrinsic pathway of coagulation?
Signup and view all the answers
Which pathway remains unaffected in patients with Haemophilia A?
Which pathway remains unaffected in patients with Haemophilia A?
Signup and view all the answers
What is the function of plasmin in the fibrinolysis process?
What is the function of plasmin in the fibrinolysis process?
Signup and view all the answers
Which condition is characterized by a deficiency in factor IX?
Which condition is characterized by a deficiency in factor IX?
Signup and view all the answers
What is the primary function of blood in the body?
What is the primary function of blood in the body?
Signup and view all the answers
Which hormone is primarily responsible for stimulating red blood cell production?
Which hormone is primarily responsible for stimulating red blood cell production?
Signup and view all the answers
What percentage of blood volume is typically comprised of red blood cells in females?
What percentage of blood volume is typically comprised of red blood cells in females?
Signup and view all the answers
Which component of blood is primarily responsible for clotting?
Which component of blood is primarily responsible for clotting?
Signup and view all the answers
What role do granular leukocytes primarily serve in the immune response?
What role do granular leukocytes primarily serve in the immune response?
Signup and view all the answers
What condition is characterized by an increased number of red blood cells?
What condition is characterized by an increased number of red blood cells?
Signup and view all the answers
Which of the following is NOT a function of blood?
Which of the following is NOT a function of blood?
Signup and view all the answers
What physical property of blood contributes to its higher density compared to water?
What physical property of blood contributes to its higher density compared to water?
Signup and view all the answers
What role does streptokinase play in clot formation?
What role does streptokinase play in clot formation?
Signup and view all the answers
Which type of anaemia is characterized by a deficiency of intrinsic factor?
Which type of anaemia is characterized by a deficiency of intrinsic factor?
Signup and view all the answers
What is a common effect of both Haemophilia A and B?
What is a common effect of both Haemophilia A and B?
Signup and view all the answers
What is the primary effect of plasmin in relation to blood clots?
What is the primary effect of plasmin in relation to blood clots?
Signup and view all the answers
Which of the following is a characteristic feature of sickle-cell disease?
Which of the following is a characteristic feature of sickle-cell disease?
Signup and view all the answers
Which component of blood primarily determines an individual's blood type?
Which component of blood primarily determines an individual's blood type?
Signup and view all the answers
What is the effect of Warfarin on the clotting process?
What is the effect of Warfarin on the clotting process?
Signup and view all the answers
Which disorder can occur as a result of the Rh incompatibility during childbirth?
Which disorder can occur as a result of the Rh incompatibility during childbirth?
Signup and view all the answers
What is the primary role of platelets in hemostasis?
What is the primary role of platelets in hemostasis?
Signup and view all the answers
What mechanism does aspirin employ to reduce blood clotting?
What mechanism does aspirin employ to reduce blood clotting?
Signup and view all the answers
Which agent is known for chelating calcium to prevent clotting in donated blood?
Which agent is known for chelating calcium to prevent clotting in donated blood?
Signup and view all the answers
The production of red blood cells (RBCs) originates primarily in which location?
The production of red blood cells (RBCs) originates primarily in which location?
Signup and view all the answers
What is the term for blood clotting that occurs within a vessel?
What is the term for blood clotting that occurs within a vessel?
Signup and view all the answers
Study Notes
Vascular Spasm
- Arteries and arterioles constrict to reduce blood flow
Platelet Plug Formation
- Requires exposure of extracellular matrix proteins:
- von Willebrand factor (vWF)
- Fibrinogen (converts to fibrin for blood clotting)
- Collagen
- Requires several steps:
- Adhesion
- Outside-in signaling - integrin activation
- Secretion
- Aggregation
- Thrombin production
Blood Clotting: Coagulation
- Extrinsic pathway
- Has fewer steps and is rapid
- Initiated by tissue factor (TF) leaking into the blood from cells outside the bloodstream
- Intrinsic pathway
- More complex and slower
- Does not require outside tissue damage
- Intrinsic pathway steps:
- Surface contact activates factor XII (FXII)
- FXIIa activates FXI and releases bradykinin (a vasodilator) from high-molecular-weight kininogen (HMWK)
- Ca2+ & FXIa activate FIX, a serine protease
- FIXa hydrolyzes FX (along with Ca2+, phosphatidylserine on activated platelets, and FVIIIa - the tenase complex)
- FVIII is a cofactor activated by thrombin from platelets
- FX is activated, leading to the common pathway
Blood Clotting: Common Pathway
- FXa cleaves prothrombin (FII) on the surface of activated platelets
- Creates a prothrombinase complex with Ca2+, phospholipids, prothrombin, FXa, and FVa
- FV is activated by small amounts of thrombin
- Fibrinogen is converted to fibrin by thrombin
- Thrombin also activates FXIII, which cross-links the fibrin clot
Fibrinolysis for Clot Localization
- The clot plugs the ruptured area
- Clot retraction is the tightening of the fibrin clot
- Fibrin threads attached to damaged surfaces of the blood vessel contract as platelets pull on them
- This pulls the edges of the wound together
- Fibrinolysis dissolves small, inappropriate clots and dissolved clots as sites of repair
- Inactive plasminogen is incorporated into the clot
- Activated to plasmin by substances in the body tissue (thrombin and t-PA)
- Plasmin digests fibrin threads and inactivates fibrinogen, prothrombin, FV, and FXII
Haemophilia A
- X-linked leading to FVIII deficiency
- Extrinsic pathway (assessed by prothrombin time (PT) by addition of TF to plasma) is fine
- Intrinsic pathway does not work (assessed by activated partial thromboplastin time - APTT) - phospholipids are added to mimic contact factor
- Affects 1:5000 males
Haemophilia B (Christmas disease)
- X-linked disorder leading to FIX deficiency
- Has a normal PT time but abnormal APTT time
- Affects 1:30 000 males
Blood Groups
- Surface of RBCs contains a range of glycoproteins and glycolipids which act as antigens
Blood Groups: Transfusions
- Blood transfusions must be carefully matched to prevent immune reactions
Blood Groups: Rhesus
- People do not normally have Rh antibodies
- They can develop them after a blood transfusion, causing problems with future transfusions
- Rh incompatibility can lead to haemolytic disease of the newborn
Thrombosis
- Blood clotting within a vessel
Atherosclerosis
- A condition involving the hardening and narrowing of arteries due to plaque buildup
Anticoagulants, Aspirin, and Thrombolytic Agents
- Warfarin: vitamin K antagonist to prevent clotting factor activation
- Vitamin K is needed for the production of many clotting factors, so blocking its action with warfarin reduces blood clotting.
- EDTA: to chelate calcium in donated blood
- Calcium is essential for the coagulation cascade
- Removing it prevents clotting
- Aspirin: inhibits TxA2 synthesis
- Involved in platelet aggregation
- Decreasing TxA2 synthesis reduces the likelihood of clot formation.
- Streptokinase: activates t-PA
- Activates plasmin, which breaks down fibrin clots
- Effectively dissolving existing clots and preventing new ones from forming.
Anaemia
- Reduced oxygen-carrying capacity
- Types:
- Iron deficiency
- Megaloblastic
- Pernicious
- Haemorrhagic
- Haemolytic
- Thalassemias
Sickle-Cell Disease
- A genetic disorder caused by a mutation in the gene for haemoglobin
- Results in misshapen red blood cells
Haemophilia
- Genetic disorders characterized by deficiencies in clotting factors
- Haemophilia A (X linked leading to FVIII deficiency)
- Haemophilia B (Christmas disease, X linked disorder leading to FIX deficiency)
Important Functions of Blood
- Transport of oxygen, nutrients, hormones, and waste products
- Regulation of body temperature, pH, and fluid balance
- Protection against infection and injury
- Regulation of blood pressure
- Maintenance of electrolyte balance
- Removal of carbon dioxide and other waste products
Blood Cell Production
- Erythropoiesis: Production of red blood cells:
- Stimulated by erythropoietin, which is secreted by the kidneys.
- Occurs in the bone marrow.
- Leukopoiesis: Production of white blood cells:
- Occurs in the bone marrow.
- Stimulated by various cytokines.
- Thrombopoiesis: Production of platelets:
- Stimulated by thrombopoietin, which is secreted by the liver.
- Occurs in the bone marrow.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
