Blood clotting and sealing wounds
Practice Flashcards
Flip to reveal answersWhat is a blood clot?
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 12 Flashcards — Blood clotting and sealing wounds
Sign up free to track progress and get spaced-repetition review schedules.
Question
What is a blood clot?
Answer
A plug of trapped blood cells held together by a mesh of **fibrin** fibres, which seals a damaged blood vessel.
Question
What two jobs does a blood clot do?
Answer
It **stops blood loss** AND acts as a **barrier that keeps pathogens out** of the wound.
Question
What causes a blood clot to form?
Answer
A **cut / damaged blood vessel** — its exposed surface activates platelets, which start the cascade.
Question
What is the role of platelets in clotting?
Answer
They **stick** to the wound, **clump** together and **release clotting factors** that start the cascade.
Question
What are clotting factors?
Answer
Chemicals released at a wound that **switch on** the cascade of reactions leading to a clot.
Question
Which enzyme converts fibrinogen into fibrin?
Answer
**Thrombin** — it turns soluble fibrinogen into insoluble fibrin.
Question
What is the difference between fibrinogen and fibrin?
Answer
**Fibrinogen** is **soluble** (dissolved in plasma); **fibrin** is **insoluble** and forms the fibre mesh of the clot.
Question
What happens to prothrombin during clotting?
Answer
Clotting factors convert inactive **prothrombin** into the active enzyme **thrombin**.
Question
What does the fibrin mesh do?
Answer
It **traps platelets and red blood cells**, forming the clot that dries into a **scab**.
Question
Put the clotting cascade in order.
Answer
Cut vessel → platelets stick / release clotting factors → thrombin formed → fibrinogen → fibrin mesh → clot / scab.
Question
Why does clotting only happen at a wound?
Answer
It is triggered by a **damaged vessel surface**; clots in healthy vessels could block blood flow, so 'no damage → no clot'.
Question
How does a clot help prevent infection?
Answer
The clot / scab **seals the cut**, forming a **physical barrier** so pathogens cannot enter the tissues.
Read the notes
Full study notes for Blood clotting and sealing wounds
Topic 3.7 hub
Defence against infectious disease
More from Topic 3.7
All flashcards in this topic
Biology exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free