Sweat glands - dog

In people, sweat glands regulate temperature by sweating and bringing warm moisture to the surface of the skin, which causes cooling as the sweat evaporates. Sweat glands are located all over the human body, cooling takes place over a greater surface area of the skin than it does in dogs. Dogs don't have this cooling system because their bodies have very few sweat glands, and most of those are in the footpads.
Dogs cool themselves primarily by the process of panting and breathing, with the moist lining of their lungs serving as the evaporating surface. A dog that is overheated will act sluggishly and gums and tongue may appear bright red, and he will be panting hard. The dog may vomit, collapse, have a seizure, and may go into a coma. An overheated dog is a real emergency situation. Get him to a veterinarian immediately. On the way to the veterinary clinic, cover him with cool wet towels. Don't use ice-cold water.