Markup View

Author: Bisected8

Jun 13th 2012 at 5:59:47 AM

How's this for a draft/starting point for a section on blood loss?

!!Circulatory System: 
The heart and all the attached blood vessels. As you most likely know, blood carries oxygen, glucose and other useful substances to the cells in your body. Excessive blood lost ("haemorrhaging" or "hemorrhaging", depending on your favorite English dialect) can kill you by virtue of there not being enough blood to get every part of the body what it needs (generally the brain dies this way first, as it needs the most energy and thus the best blood supply).

There are two types of blood vessel; arteries and veins, distinguished by whether or not they carry blood away from or back to the heart. The former tend to be under more pressure (the heart is an extremely powerful pump, HighPressureBlood is perfectly possible, although it usually happens in "spurts" as the heart beats), so major arteries are the "weak point" of the system (as well as the points where you can feel a pulse, since you're essentially feeling the change in pressure every time the heart pumps). While veins have lower blood pressures, since they essentially let the blood trickle back as it's displaced by the blood that's been pumped through smaller vessels (not to mention they tend to have valves to help keep the blood flowing in the right direction, which also slows bleeding), larger ones still hold the same risks (although the character in question won't bleed out as quickly, which makes slower, but still serious, bleeding just as plausable). The heart is another weak point (although, while a wound to the heart is almost always portrayed as a death sentence in fiction, with quick medical treatment 1 in 3 patients with stab wounds to the heart survive; not great odds, but surprisingly high). The medical term for any severe blood loss is "desanguination" but many TV shows will use the related (and cooler sounding) term "exsanguination" (the loss of ''all'' the body's blood).

Losing more than a pint of blood is typically the point at which things become dangerous (hence why that's generally the amount taken when some is donated), although it's possible to survive losing up to 30% (about 2 pints in a healthy adult) of your blood without needing a transfusion. Despite this, in fiction it tends to be more dramatic if someone needs a transfusion so don't expect it to come up.