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"Q: What are platelets also called?"

"A: Thrombocytes."

"Q: What are platelets made from?"

"A: They are fragments of large cells called megakaryocytes that have broken apart."

"Q: Do platelets have a nucleus?"

"A: No

"Q: What special movement ability do platelets have?"

"A: They have amoeboid capabilities

"Q: How long do platelets live?"

"A: Around 10 days."

"Q: What is hemostasis?"

"A: Hemostasis is the stoppage of blood loss after an injury."

"Q: How many clotting factors are involved in blood clotting?"

"A: There are 13 clotting factors."

"Q: What is the system that stops excessive coagulation called?"

"A: The fibrinolytic system

"Q: Why can blood flow smoothly inside vessels?"

"A: Because the inner lining of blood vessels (endothelium) is smooth and slick

"Q: What happens when there is a break or damage to the vessel lining?"

"A: It triggers multiple reactions to maintain hemostasis and prevent blood loss."

"Q: What are the three major reactions in hemostasis?"

"A: 1. Blood vessel spasm\n2. Platelet plug formation\n3. Coagulation"

"Q: What happens during a blood vessel spasm?"

"A: Smooth muscle in the vessel wall contracts

"Q: How do platelets assist during a blood vessel spasm?"

"A: They release chemicals that enhance vessel contraction and help reduce bleeding."

"Q: What happens during platelet plug formation?"

"A: Platelets adhere to the damaged site and pile up to form a temporary plug that seals small vessel injuries."

"Q: What happens during coagulation?"

"A: Clotting factors (procoagulants) trigger a series of chemical reactions that convert fibrinogen into fibrin

"Q: What is fibrinogen and what does it become during coagulation?"

"A: Fibrinogen is a plasma protein that

"Q: What substance is essential for almost every step of clotting?"

"A: Calcium (Ca²⁺)."

"Q: What is the sequence of chemical events in coagulation?"

"A: 1. Tissue injury → release of prothrombin activator (requires Ca²⁺)\n2. Prothrombin activator converts prothrombin → thrombin\n3. Thrombin converts fibrinogen → fibrin (also requires Ca²⁺)\n4. Fibrin forms the clot"

"Q: What is the correct order of clot formation components?"

"A: Prothrombin activator → Prothrombin → Thrombin → Fibrinogen → Fibrin."

"Q: What vitamin is necessary for blood clotting

and why?"

"Q: What happens if the body lacks vitamin K?"

"A: Insufficient prothrombin production

"Q: Where can vitamin K be synthesized naturally in the body?"

"A: It is produced by bacteria in the intestines after birth."

"Q: What are the two clotting pathways (cascades)?"

"A: Intrinsic and Extrinsic pathways."

"Q: What activates the intrinsic clotting pathway?"

"A: Damage to the inner lining of a blood vessel (endothelial injury)."

"Q: What activates the extrinsic clotting pathway?"

"A: Tissue damage outside the vessel wall."

"Q: What do both the intrinsic and extrinsic pathways lead to?"

"A: They share a common end — the formation of a blood clot."

"Q: What determines whether blood will clot or not?"

"A: A balance between procoagulants (clot promoters) and anticoagulants (clot inhibitors)."

"Q: What prevents clotting under normal conditions?"

"A: The smooth

"Q: What can trigger unwanted clot formation?"

"A: A rough spot or damage in the vessel lining (e.g.

"Q: What is a thrombus?"

"A: A stationary blood clot that forms within a blood vessel."

"Q: What is an embolus?"

"A: A traveling blood clot that moves through the bloodstream."

"Q: How do fibrin threads regulate clot size?"

"A: They signal thrombin when the clot is large enough

"Q: What does heparin do during clotting?"

"A: Heparin is an antithrombin that interferes with prothrombin activator

"Q: What happens when platelets encounter a rough surface in a vessel?"

"A: They stick to the surface and may start forming a clot."

"Q: What do procoagulants do?"

"A: They promote clot formation."

"Q: What do anticoagulants do?"

"A: They inhibit or slow down clotting."

"Q: What is the purpose of the fibrinolytic system?"

"A: It breaks down clots after healing to restore normal blood flow and prevent blockage."