Final answer:
Sebaceous glands originate from the dermis layer of the skin and are associated with hair follicles. They produce sebum, which aids in skin hydration and protection. The epidermis is the outermost layer of the skin, producing keratin-filled cells from its basal layer.
Step-by-step explanation:
The sebaceous glands, which are responsible for producing sebum, an oily substance that helps waterproof the skin and hair, originate from the dermis layer of the skin. These glands are associated with hair follicles and can be found throughout the dermis, except on palms and soles where hair is absent. The sebaceous glands release their secretions into the hair follicles, or directly onto the skin surface in hairless areas. The sebum they produce plays a critical role in maintaining the hydration and flexibility of the skin as well as providing a barrier against the external environment.
Regarding the development of skin cells, the epidermis is the outermost layer of the skin that serves as a protective barrier. It is composed of layers of keratin-filled cells called keratinocytes, which originate from the deepest layer called the stratum basale or basal layer. This layer continuously divides and gives rise to new cells that migrate towards the skin surface, becoming part of the epidermis.