It is a set of 4 conditions as set by the Harvard School of Medicine for diagnosis of irreversible coma. They are:

Unreceptivity and unresponsiveness
Lack of movements or breathing
Absent reflexes
Flat electroencephalogram (confirmatory)

These conditions also are to be met:

Body temperature >= 32 C
Not under the influence of CNS depressants 

3 types of brain death are:

Cortical / cerebral death
brain stem death
whole brain death

It is also called secondary drowning or near drowning. It refers to a peron who was resuscitated after drowning and survives for 24hours. He may develop hypoxemia resulting in brain damage, cerebral edema, pulmonary edema, pneumonitis, myocardial anoxia, cardiac arrhythimas, electrolyte imbalance, metabolic acidosis, hemoglobinuria, fever and sepsis. Death occurs in about 20% of victims. 5-10% of those who survive can have severe neurological defects.

In dry drowning, water does not enter the lungs. Due to rapid entry of water into the nasopharynx and larynx, the larynx undergoes immediate sustained spasm, which is the cause of death. There may be production of mucus plugs and froth. It occurs mainly in childer and adults under the influence of alcohol or sedative hypnotics.

It is also known as primary drowning. In this, large amounts water enter the lungs. The person experiences severe chest pain. Death occurs in minutes due to cardiac arrest or ventricular fibrillation.

Types of drowning are:

Wet drowning
Dry drowning
Secondary drowning / post immersion syndrome / near drowning
Immersion syndrome / hydrocution / submersion inhibition

Carboxyhemoglobin is the product formed by the combination of carbon monoxide and hemoglobin. It is produced in red cells when a person inhales carbon monoxide. It does not have the capacity to transport oxygen. Large quantities of carboxyhemoglobin in blood can lead to death.

Antemortem blisters are mostly produced during burns. 
Features of antemortem blisters:

surrounded by an area of hyperemeia
floor is reddened with swelling of papillae

Postmortem blisters (blisters of putrefaction) are formed 18-24 hours after death due to putrefaction and production of gases which force blood, air to liquid fat into the superfical layers of skin forming blisters. They are found first in the lower surface trunk and thighs where there is more fluid collection due to hypostatic edema.
Features of postmortem blisters:

no surrounding hyperemeia
floor is not reddened

Localised swelling of the skin containing a pocket of fluid collected in the upper layers of the skin. Blisters can be produced by burns. Post mortem blisters are formed by production of gas during putrefaction.

Fresh – bright red
12-24hrs – Bright scab (by drying of blood and lymph)
2-3 days – reddish brown scab
4-7 days – brownish black scab
>7 days – scab falls off leaving a depigmented area which slowly gets pigmented