Haemostasis
Haemostasis is the process by which blood loss is prevented. This happens through three basic mechanisms:
- Vascular Spasm – blood vessel damage stimulates pain receptors to cause immediate smooth muscle contraction within its wall; this reduces blood loss rate for up to 30 minutes, during which other haemostatic mechanisms are triggered.
- Platelet Plug Formation – platelets which come into contact with damaged blood vessel parts begin to enlarge, become irregular, sticky, and start adhering to collagen fibres; ADP (adenosine diphosphate) and enzyme synthesis triggers the formation of other substances, activating more platelets to adhere to the original platelets, forming a platelet plug, which is then reinforced by fibrin threads.
- Blood Coagulation a.k.a. Blood Clotting -whilst blood within the vessels maintains its liquid state, blood outside the vessels thickens and forms a gel (serum) which separates from the liquid. Blood serum is blood plasma without its clotting proteins, whilst the gel is the clot, which contains insoluble fibres that trap the cellular components of the blood.
Blood Coagulation
Blood coagulation is the process of clot formation – a process which involves various chemicals referred to as coagulation factors.
There are 3 basic stages for coagulation…
Stage 1: Formation of Prothrombin Activator
Stage 1 involves the formation of prothrombin activator, initiated by the extrinsic and intrinsic pathway of blood clotting.
Stage 2: Conversion of Prothrombin into Thrombin
Following the formation of prothrombin activator, it binds to Ca2+ ions (Calcium Ions), causing the conversion of prothrombin into thrombin.
Stage 3: Conversion of Fibrinogen into Fibrin
Thrombin and Ca2+ ions trigger the conversion of Fibrinogen (soluble) to Fibrin (insoluble).
Thrombin activates Factor XIII (Antihemophilic Factor) which strengthens and stabilises the fibrin clot.
Through a positive feedback effect, Thrombin accelerates the formation of prothrombin activator through Factor V (Proaccelerin), which further accelerates the production of more Thrombin.
The formed clot plugs the ruptured area of the blood vessel, preventing haemorrhage. This is followed by permanent repair of the blood vessel.
Additional Factors related to Haemostasis
Vitamin K
Efficient clotting requires Calcium as well as Vitamin K, which is required for prothrombin formation and other coagulation factors by the liver. Vitamin K is formed by the human intestinal bacteria, and can also be found in foods such as spinach, cabbage, cauliflower, and liver.
Thrombosis
Thrombosis is the formation of a clot (thrombus) within an intact blood vessel. Thrombosis is caused within blood vessels containing sluggish blood flow, and when platelets stick to fatty deposits on the blood vessels’ inner surface. A thrombus can either dissolve or else grow and eventually block the blood vessel.
Embolism
Embolism happens when a part of the thrombus breaks off from its original site forming an embolus, moves along the blood stream until it reaches a small blood vessel and blocks it.
Did you find the above nursing information useful? Follow us on Facebook and subscribe to receive new blogposts by email as soon as they’re published 🙂
Claire is keen about public education on health-related subjects as well as holistic patient-centered care. She is also passionate about spreading awareness on the negative effects that domestic abuse leaves on its victims’ mental, emotional, social and physical wellbeing.
Claire aspires to continue studying following completion of her Nursing Degree, because she truly believes in lifelong education.
- The NUPO Diet Review: trying NUPO before going under the knife - 19/12/2023
- Antimicrobial Resistance Symposium - 11/11/2023
- Examination of the Abdomen for Nursing Students - 01/07/2023
