lecture 9 Flashcards
(19 cards)
What are the main functions of blood?
Blood performs the following functions:
* Substance distribution/transportation (gases, nutrients, waste products, hormones)
* Body maintenance (body temperature, pH, osmosis)
* Body protection (foreign substances)
These functions are crucial for maintaining homeostasis in the body.
What is the composition of blood?
Blood is composed of:
* Liquid plasma
* Formed elements (erythrocytes, leukocytes, platelets)
Formed elements are crucial for various physiological functions, including oxygen transport and immune response.
What is a thrombus?
A thrombus is a clot that develops and persists in an unbroken blood vessel.
Thrombi can block circulation, leading to tissue death.
What is an embolus?
An embolus is a thrombus that is freely floating in the bloodstream.
Pulmonary emboli can impair oxygen acquisition, and cerebral emboli can cause strokes.
What is hemostasis?
Hemostasis is a series of reactions designed for the stoppage of bleeding, leading to coagulation (blood clotting).
This process is vital for preventing excessive blood loss following injury.
What role do platelets play in hemostasis?
Platelets function in the clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels.
Platelets do not stick to each other or the endothelial lining under normal conditions.
What triggers the coagulation process?
Coagulation is triggered when injured tissue releases tissue thromboplastin, leading to platelet aggregation and activation of clotting factors.
This cascade ultimately results in the formation of a stable blood clot.
What is fibrinolysis?
Fibrinolysis is the removal of unneeded clots, primarily mediated by the enzyme plasmin.
Plasminogen is activated to plasmin by tissue plasminogen activator (t-PA).
What are anticoagulant drugs used for?
Anticoagulant drugs are used to prevent blood clots in conditions like:
* Arteriosclerosis
* Atrial fibrillation
* Acute coronary syndrome
* Deep venous thrombosis
* Pulmonary embolism
They also provide anticoagulation during procedures like hemodialysis.
How does heparin work?
Heparin inhibits thrombin activity and enhances the activity of antithrombin III.
It is administered subcutaneously or intravenously and is derived from animal intestines.
What is the mechanism of action of warfarin?
Warfarin is a vitamin K antagonist that prevents the liver from producing vitamin K-dependent clotting factors.
This interruption in clotting factor formation helps to prevent clotting.
What is sickle-cell anemia?
Sickle-cell anemia results from a defective gene coding for an abnormal hemoglobin called hemoglobin S (HbS).
Symptoms include pain, prolonged bleeding, and joint disability due to sickle-shaped RBCs.
What treatments are available for anemia?
Treatments for anemia include:
* Blood transfusions
* Vitamin B12 supplements
* Iron supplements
* Erythropoietin-like drugs
* Hydroxyurea
These treatments address underlying causes and symptoms of anemia.
What is hemophilia?
Hemophilia is a hereditary bleeding disorder caused by a lack of clotting factors.
Hemophilia A is the most common type, resulting from a deficiency of factor VIII.
What is the role of vitamin K in blood clotting?
Vitamin K is required for the synthesis of certain clotting factors in the liver.
A deficiency can lead to impaired blood coagulation and increased bleeding risk.
Fill in the blank: A thrombus that is freely floating in the bloodstream is called an _______.
Embolus
Emboli can lead to serious complications such as strokes or pulmonary embolism.
True or False: Aspirin irreversibly inhibits platelet aggregation by acetylating cyclooxygenase.
True
This action prevents the formation of thromboxane A2, a potent platelet agonist.
What are thrombolytic drugs used for?
Thrombolytic drugs are used to lyse (dissolve) blood clots once they have formed.
They convert plasminogen in clots to plasmin, facilitating clot dissolution.
What are the primary types of anticoagulant drugs?
The primary types of anticoagulant drugs include:
* Heparin
* Low-molecular weight heparin (LMWH)
* Warfarin
* Direct thrombin inhibitors
* Factor Xa inhibitors
Each type has a specific mechanism of action and therapeutic application.
