<unk>  refers to the loss of blood.<unk>  can happen inside the body (internally) or outside the body (externally). It may occur:
Inside the body when blood leaks from blood vessels or organs
Outside the body when blood flows through a natural opening (such as the vagina, mouth, or rectum)
Outside the body when blood moves through a break in the skin
Always seek emergency assistance for severe<unk> , and if internal<unk>  is suspected. Internal<unk>  can rapidly become life threatening, and immediate medical care is needed.
Serious injuries don't always bleed heavily, and some relatively minor injuries (for example, scalp wounds) can bleed quite a lot. People who take blood-thinning medication or who have a<unk>  disorder such as hemophilia may bleed excessively and quickly because their blood does not clot properly.<unk>  in such people requires immediate medical attention.
Direct pressure will stop most external<unk> , and is the most important first aid step.
Always wash your hands before (if possible) and after giving first aid to someone who is<unk> , in order to avoid infection.
Try to use latex gloves when treating someone who is<unk> . Latex gloves should be in every first aid kit. People allergic to latex can use a non-latex, synthetic glove. You can catch viral hepatitis if you touch infected blood, and HIV can be spread if infected blood gets into an open wound -- even a small<unk> .
Although puncture wounds usually don't bleed very much, they carry a high risk of infection. Seek medical care to prevent tetanus or other infection.
Abdominal and chest wounds can be very serious because of the possibility of severe internal<unk> . They may not look very serious, but can result in shock. Seek immediate medical care for any abdominal or chest wound. If organs are showing through the wound, do not try to push them back into place. Cover the injury with a moistened cloth or bandage, and apply only very gentle pressure to stop the<unk> .
Blood loss can cause bruises (blood collected under the skin), which usually result from a blow or a fall. They are dark, discolored areas on the skin. Apply a cool compress to the area as soon as possible to reduce swelling. Wrap the ice in a towel and place the towel over the injury. Do not place ice directly on the skin.
Bleeding
Hemostasis
Wound healing
Coagulation
Swelling 
Thrombosis
Contractility
Noma causes