Dermis

• Hypodermis, also known as subcutaneous tissue, is composed of adipose tissue, which can be converted to ATP.
• Dermis is the 2nd major skin region and the 2nd layer of skin.
• Dermis is composed of dense connective tissue which contains collagen and elastic fibers.
• Dermis contains fibroblasts, nerve endings, smooth muscle, glands, blood vessels, and hair follicles.
• Fibroblasts in the dermis help form connective tissue.
• The majority of tissue functions are found in the dermis.
• Collagen fibers of the dermis are oriented in many different directions and can resist stretch.
• Stretch marks are damage in the dermis due to overstretched skin that appears in the epidermis.
• The papillary layer is a thin connective tissue layer in the dermis that contains blood vessels, with capillaries being the smallest blood vessels in the vascular system, transporting blood, nutrients and oxygen to cells in organs and body systems.
• Dermal papillae are ridged on hands and feet, creating fingerprints, and the pattern is genetically determined.
• The reticular layer is the deepest layer of the dermis, accounting for 80% of the dermis.
• An incision made parallel to cleavage lines results in less gapping, faster healing, and less scar tissue.
• The papillary layer is located in the outer part of the dermis, below the epidermis.
• Dermal papillae are projections that extend up into the epidermis, removing waste and helping to regulate body temperature.
• More collagen fibers are oriented in some directions than in others, producing cleavage lines.
• Cleavage lines, also known as tension lines, are areas where skin is most resistant to stretching, due to the orientation of collagen fibers, and are important in scarring.
• An incision made across cleavage lines can gap, increasing the time needed for healing and resulting in increased scar tissue formation.