Topic 1: Blood clotting Flashcards

1
Q

When a _______ _______ is cut or damaged, a cascade of events follows, resulting in a blood clot (aka a _________).

A

blood vessel

THROMBUS

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2
Q

What is the advantage of a blood clot forming? (2 points)

A
  1. Minimises blood loss.

2. Prevents {pathogens entering/infection}.

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3
Q

What if the clotting mechanism is triggered in the WRONG place? (1 point + 2 examples)

A
  1. Problems can arise

e. g. stroke, heart attack

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4
Q

What triggers blood clotting?

2 points

A
  1. Blood clotting is triggered by DAMAGE to (ENDOTHELIUM / endothelial cells of) a blood vessel wall (endothelial dysfunction)
  2. This can happen due to:
    - HIGH BLOOD PRESSURE
    - Components of cigarette smoke, eg. free radicals, nicotine
    - Viruses, chemicals, drugs/medicines
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5
Q

________ (fragments of blood cells) attach to damaged vessel wall

  • usually _________ ______ - they change into spheres with long projections
  • they stick to exposed collagen & form a __________ _________ _______
  • they release _____________ and also PAF (platelet activating factor) to activate more platelets

This triggers a complex cascade of chemical reactions which forms a blood clot (aka ________).

A

Platelets

flattened discs

temporary platelet plug

thromboplastin

thrombus

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6
Q

Key Summary: Explain the process of blood clotting

5 steps

A
  1. THROMBOPLASTIN (enzyme) released from PLATELETS AND DAMAGED TISSUE
  2. thromboplastin, in presence of CALCIUM IONS and VITAMIN K converts PROTHROMBIN (inactive enzyme) into the enzyme THROMBIN
  3. thrombin converts FIBRINOGEN (plasma protein) into FIBRIN
  4. MESH OF INSOLUBLE FIBRIN fibres forms
  5. platelets + red blood cells get trapped in the mesh forming a BLOOD CLOT
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7
Q

Platelet definition (1 point)

A
  1. A cell fragment that releases thromboplastin
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8
Q

Thromboplastin definition (1 point)

A
  1. A soluble enzyme that catalyses the conversion of prothrombin to thrombin (globular)
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9
Q

Prothrombin definition (1 point)

A
  1. A soluble plasma protein (globular)
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10
Q

Thrombin definition (1 point)

A
  1. An enzyme that catalyses the conversion of fibrinogen to fibrin (globular)
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11
Q

Fibrinogen definition (1 point)

A
  1. A soluble plasma protein (globular)
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12
Q

Fibrin definition (1 point)

A
  1. An insoluble fibrous protein that forms a mesh to trap red blood cells.
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13
Q

Key Summary: Explain the role of blood clots in heart disease
(5 steps)

A
  1. blood clots can BLOCK the LUMEN of the CORONARY ARTERIES
  2. preventing or reducing the FLOW OF BLOOD AND SUPPLY OF OXYGEN and glucose to heart MUSCLE tissue
  3. {no/less} aerobic respiration - anaerobic respiration instead in cells – produces lactic acid – {inhibits enzymes/toxic} and {causes pain /less ATP produced}
  4. if prolonged may lead to {permanent damage/death} of {tissue/cells}
  5. resulting in a heart attack

Note: For stroke – change the statements slightly

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14
Q

If changes to lifestyle do not work, or the risk is high, doctors may prescribe drug treatments.

Name the 3 types of drugs (3 types of drugs)

A
  1. Antihypertensives
  2. Platelet inhibitors
  3. Anticoagulants
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15
Q

Give an example of antihypertensives

A

calcium channel blocker

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16
Q

Give an example of platelet inhibitors

A

Aspirin

17
Q

Give an example of anticoagulants

A

Warfarin

18
Q

What is the benefit of antihypertensives (1 point)

A
  1. Reduce blood pressure
19
Q

What is the benefit of platelet inhibitors? (2 points)

A
  1. Reduce stickiness of platelets, preventing them sticking together,
  2. so blood clots cannot form or grow
20
Q

What is the benefit of anticoagulants? (1 point)

A
  1. Slow down clotting by reducing fibrin formation
21
Q

What is the side effect of hypertensives? (1 point)

A
  1. Dizziness
22
Q

What is the side effect of platelet inhibitors? (1 point)

A
  1. Gastrointestinal bleeding
23
Q

What is the side effect of anticoagulants? (1 point)

A
  1. Internal bleeding