As it is for a majority of animals in the kingdom fauna, skin is known to be the largest organ in the body of a dog. Apart from its usual use of regulating temperatures and acting as a protective barrier to the internal organs, the sensitive skin of a dog gives it the keen sense of touch that helps them survive even in the toughest surroundings. There are some species of dogs which have more skin when compared to other species, however, in proportion to the body weight, their skin spreads in the range of 12-24% altogether. There are three layers that can be distinguished in the body of a dog which is similar to a majority of mammals. The outermost layer is called the “Epidermis”, the middle layer is named the “dermis” and the innermost layer is named “sub cutis”. There are many other important parts such as hair, claws, and muscles and fat those surround the skin as well. Let us now look into each of the layers in detail.
The Outer layer – Epidermis
Being composed of a variety of cells that have different and unique components, altogether making the largest protective barrier of a dog’s body, Epidermis is the outer most layer of the skin. It has multiple uses to the body of a dog. The cells that it is made of are as follows.
- Langerhans cells
- Merkel cells.
Keratinocytes are specially made for the renewal purpose of the skin which is generally referred to as ketatinization. In this process, new cells are created and are pushed upward while the older cells break off the skin with the sweat. The cells which are dead and gathered in the surface of the skin create a barrier for unwanted agents from the outer world as well. The renewal and replacement of new cells happens continuously throughout the dog’s life. It is a crucial process to keep the skin of healthy, however the lack of nutrition, changing of hormone levels and the problems that occur in the tissues cause problems in the mentioned process. Genetic problems and diseases caught from the outer surroundings can also cause problems in the keratinization process.
Located around the very base of the epidermis, Melanocyte cells are where the roots of skin hair and the sweat glands exist. This also produces melanin to protect skin from the harmful UV rays. Genetics and the hormone levels can change the amount of melanin produced and it may differ from one species to another.
While being the protective barrier of the body, skin is also a doorway for many infections and diseases especially when it comes to dogs. Being a part of the body’s immune system, Langerhans cells do a very important part when it comes to responding the alien substances that come through the skin and eventually cause skin irritations.
Merkel cells are a special kind to the canine breed since they are what trigger the sensory organs in the skin such as whiskers. These help providing sensitive information and are specifically built for that need.
Moving on to the layers below epidermis, you find the basement membrane zone which is under the epidermis and on top of dermis, the middle layer. This is more of a safe layer in between the main layers mentioned above. It, however, can be damaged from a number of auto immune conditions and some of the common skin diseases of dogs as well.
Dermis is more of a feeder of nutrients for the epidermis. The vessels of blood that feeds and nourishes the dermis are located in the dermis. These also maintain the body temperature and it is responsible to the body responses such as touch and the feel of pain. This is also the region that gives the feelings of heat and cold as well. With the proteins like elastin and collagen, dermis gives the elasticity to the skin. Same as the other layers, Dermis also does its protective service for the body by repelling the infectious agents from entering the inside of the body.
Skin Appendages are almost everything except the regular layer of skin in a dog’s body. These include claws, hair, oil glands, sweat glands and other things that grow with epidermis and dermis as a base. Dogs have compound hair follicles that have 3-15 hair strands to one pore. When a dog is born to the world they have simple hair follicles which as the dog grow up change to be compound hair follicles.
The condition of the skin directly affects the growth of their hair and the nutrition and the hormones that affect the skin can be visible through hair for an observant eye. Shedding of dog hair that usually happens by the end of spring can be thus changed due to factors such as temperature and the climate in the surroundings. Although the nature of dog hair differs with the species, there are general factors that affect everyone such as genetics and hormones. The shape and the length of hair may also depend on the environment factors and certain drugs as well.
The coat of hair in a dog is there as a barrier for the UV rays of the sun and other harmful substances from the other world. This may also help them to regulate and keep the body temperature in line as well from the dead air that is trapped in between their hairs. For this reason, it is required your dog to be kept dry most of the time. This is why the dog breeds from the regions away from the equator tend to have a longer and fluffier coat of hair rather than the dog breed from tropical regions. They also tend to have a thicker yet fewer numbers of hairs in order to trap the heat easier and for a long time as the air may flow through the strands easily.
Progressing to the oil glands, which are another important part of the skin of a dog, these are basically what keep the skin moisturized and pliable. There are some regions in a dog’s body where there’s a larger spread of oil glands when compared to others, such as the paws, neck and the chin area. Oils those are emitted through the glands are mostly consisted of fatty acids and these also help the sheen that the coats of hair get when it is combed well. There are sweat glands which help the disposal of unwanted substances through the skin which also help releasing the body heat as well. However, the dogs do the major part of releasing heat through their drool or heave panting.
Coming to the innermost layer of a dog’s skin — Subcutis — this is the part where the muscles and fat is stored. The literal meaning of the word subcutis is “under the skin”. Working as an absorber for the physical shocks dogs get, as a container for fluids and energy, subcutis is largely responsible for the insulation process as well.