When you get a cut your body response is to swell to help stop the bleeding.
Blood vessels can be damaged by transection or rupture, at the point of damage whole blood will flow from the damaged blood vessel' this is called a haemorrhage. HEMO is blood RRHAG is excessive flow or 'bursting forth' When this occurs the blood system responds in a number of ways. The first response to the damaged area of the blood vessel , is that the blood vessel will contract i.e. spasm this will considerably slow or reduce the volume of blood loss, also the platelets move to the cut in the vessel wall. If the damage to the blood vessel is small the platelets form a plug by clumping which may stop the bleeding. A more complicated process of sealing off holes in blood vessels is called coagulation or clotting , this is where the blood forms a solid mass to seal the opening from the damaged area, this is called a blood clot. After several intermediate steps the protein fibrinogen in the blood is converted into sticky strands of fibrin. There are areas of the body where blood is stored these are called reservoirs, these ensure the circulating blood volume, the reservoirs include the spleen and the liver and are able to release several hundred millilitres of stored blood. There are also groups of veins, such as the large abdominal veins that store several hundred millilitres of blood.
How much blood can an adult lose before the system is unable to function.
the blood has several way of dealing with haemorrhage, the first is the constriction of the blood vessel , The second is when platelets form a plug, the third is by clotting and forming a solid mass over the affective area. When the haemorrhage is serious and there is substantial loss of blood, the system can use blood that has ben stored in reservoirs ie the liver and the spleen, blood is also stored in the abdominal veins.
A blood vessel may be damaged by transection (cutting across) or rupture.
At such points, a volume of whole blood can flow out of the blood vessels. This escape of
blood from the blood vessels is called hemorrhage.
HEMO = blood
RRHAGE = excessive flow ("bursting forth")
Vascular contraction. The first response to a cut or ruptured vessels is contraction (spasm) of the blood vessel itself. This may considerably reduce the volume of blood loss.
Platelet Plug. If the hole is small, a plug formed by clumping of the platelets
may be adequate to stop the bleeding.
Blood Clotting. There is a complicated process for sealing off holes or ends of blood vessels after a cut or rupture.
By this process, called coagulation or clotting, the blood forms a solid mass to seal the opening where the blood is escaping. The mass is called a blood clot.
After many intermediate steps, the protein fibrinogen of the blood is converted into sticky strands of fibrin. These sticky strands adhere to the wall of the opening and form a meshwork in the opening, which traps RBCs and plasma. Thus, the opening is sealed.
Hematoma. A hematoma is a collection of blood, usually clotted, in an organ, space, or tissue. When found immediately beneath the skin, it will produce a purplish spot or mark.
With time, as the clot is broken down and resorbed, the hematoma changes color and becomes smaller.
Mobilization of Blood Reservoirs
Mobilization of Blood Reservoirs. Certain areas of the body contain enough blood that they can be used as reservoirs to maintain the circulating blood volume. This is important when a volume of blood has been lost through hemorrhage.
Among these are the spleen and the liver, whose sinuses together can release several hundred milliliters of blood. Also important are several groups of veins, including the large abdominal veins, which can also provide several hundred milliliters of blood.
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