Their ducts are like those of the eccrine glands, but they open into hair follicles instead of the surface of the skin. These glands are innervated by postganglionic sympathetic nerve fibers that are nor-adrenergic. They are under the influence of sex hormones. The cells of the hair matrix produce the medulla, cortex and cuticle of the hair. Each follicle has an associated sebaceous gland and arrector pili muscle .
Hairs represent hard keratin .
Sebaceous glands Sebaceous glands feature the holocrine type of secretion in which all of the cell is secreted onto the skin surface via the follicular canal. Their secretion is referred to as sebum . Sebaceous glands are under the influence of sex hormones. There are sebaceous glands located at the margins of the lips and in the areola of the nipple that open directly onto the skin surface. Nails Like hairs, represent hard keratin .