• When the skin is cut, microorganisms have an entry point to get into the body
  • The first line of defence is compromised
• In order to minimise the risk of substantial?blood loss?and entry of?unwanted microorganisms, the blood starts to clot to?seal the wound
• In response to?blood vessel damage, platelets form a temporary?plug?to stem bleeding
  • Platelets are?cellular fragments?that make up one component of the blood
• They release chemicals called?clotting factors?that trigger a?chemical cascade which results in blood clotting

The blood is made up of 4 key components including plasma, red blood cells, white blood cells and platelets

• The chemical cascade, triggered by the clotting factors, involves a large number of steps and several plasma proteins
  • First of all, the?clotting factors?stimulate the release of the enzyme?thrombin
  • Thrombin catalyses the conversion of the soluble protein?fibrinogen?into?fibrin, which is insoluble
  • Fibrin forms a?mesh?that traps more platelets and blood cells to prevent entry through the wound
    • A small initial stimulus is?amplified?to produce a large amount of fibrin so that the wound is quickly sealed
  • Exposure to air results in the hardening of the mesh to create a?scab

Blood clot formation

Causes of blood clots in the coronary arteries

• A blood clot in the?coronary arteries?is called?coronary thrombosis
• Several factors may?increase the risk?of coronary thrombosis developing:
  • Atherosclerosis in the coronary arteries?results in a build-up of layers of fatty material (plaque) causing?damage to the?endothelium?wall
    • Bulging of?the?lumen?of the artery causes a blockage which reduces the space for blood flow
    • Deposition of?calcium ions?can worsen the situation by hardening the endothelium
    • Lesions?can also sometimes form due to?ruptures?in the atheroma

Consequences of blood clot formation in the coronary arteries

• Occlusion?of the?coronary arteries?is a common problem that can lead to significant health issues such as?coronary heart disease
• The coronary arteries deliver?oxygen?and?nutrients?to the cardiac muscle tissue
• If a blood clot forms in the coronary arteries, it can cause?blockages
• A blockage means that the tissue beyond that point is deprived of oxygen and nutrients, so it is unable to?respire?aerobically
• As a result, cells are unable to produce a?sufficient amount of?ATPwhich inhibits normal cardiac muscle contraction resulting in?irregular?and?uncoordinated?movement called?fibrillation
  • If not rectified, either naturally or through medical intervention, fibrillation could lead to?death
• A?heart attack?(myocardial infarction) may also occur in situations where the blood supply is completely inhibited so that the cardiac muscle tissue starts to die
  • This can be fatal

Risk factors for coronary thrombosis

• There are several factors which have shown a clear?correlation?with increased chances of coronary thrombosis or heart attacks
• The main risk factors for include:
  • Genetic factors
  • Age and sex
  • High blood pressure
  • Smoking
  • High concentrations of low-density lipoproteins (LDLs)?
  • Diabetes
  • Obesity
  • Lack of exercise