Dermis or corium is the inner part of skin mainly composed of connective tissue.it is mesodermal in origin. Dermis is derived embryologically from dermatome.dermis is 2 to 3 times thicker than epidermis.
structure of dermis these are two parts
1)outer part: pars papillaris
2)inner part: pars recticularis

Dermis of mammalian skin is mainly composed of:
Connective tissue:
- The dermis is primarily made up of connective tissue, which provides support and structure to the skin.
- Connective tissue is composed of collagen fibers, elastic fibers, and ground substance.
- Collagen fibers give strength and flexibility to the skin, allowing it to resist stretching and tearing.
- Elastic fibers provide elasticity to the skin, allowing it to return to its original shape after being stretched.
Fibroblasts:
- Fibroblasts are the main cells found in the dermis that produce collagen and elastic fibers.
- They are responsible for maintaining the structural integrity of the dermis.
Blood vessels:
- The dermis contains a network of blood vessels that supply nutrients and oxygen to the skin cells.
- Blood vessels also help regulate body temperature by dilating or constricting, which can increase or decrease blood flow to the skin.
Nerve endings:
- The dermis is rich in nerve endings that allow us to perceive touch, temperature, and pain.
- These nerve endings transmit sensory information to the brain, enabling us to interact with our environment.
Appendages:
- The dermis contains various appendages, including hair follicles, sweat glands, and sebaceous glands.
- Hair follicles produce hair, sweat glands secrete sweat, and sebaceous glands produce sebum, an oily substance that moisturizes the skin.
Overall, the dermis is a complex structure composed mainly of connective tissue, which provides support, strength, and flexibility to the skin. It also contains blood vessels, nerve endings, and various appendages that contribute to the overall function and health of the skin.