There are three main types of skin gland: sebaceous, apocrine and eccrine.
Sebaceous glands are located near the hair follicles and their function is to produce sebum, a natural oil that protects and waterproofs the skin and coat. Grooming maintains healthy skin by stimulating the production of sebum and aids its distribution across the coat resulting in a natural glossy shine.
Whilst found all over the body, the apocrine sweat glands are not particularlty useful for cooling purposes, their main function being territorial scent marking.
The eccrine (watery sweat producing) glands are found on the pads of the paws. As an alternative to sweating and in order to lose heat, a cat will lick its fur spreading saliva that cools the animal as it evaporates. Occasionally they will pant to lower their body temperature and cool down. Panting caused by anxiety, stress or discomfort is always a cause for concern as the heart is under strain and every measure should be then taken to alleviate the cause of stress.
The skin is very thin and can be easily damaged by rough handling or by using inappropriate grooming equipment and specialist trimmers are the safest tool for any tangles or mats.