Which gland is described as small and sac-like, found in the dermis, with secretions that typically empty into hair follicles?

The sebaceous glands are indeed small and sac-like structures located in the dermis layer of the skin. Their primary function is to produce an oily substance called sebum, which is essential for lubricating and protecting the skin and hair. The secretions of sebaceous glands typically empty into hair follicles, where the sebum helps to moisturize the skin and provide a barrier against external factors. This association with hair follicles is a distinctive characteristic of the sebaceous gland, setting it apart from other gland types in the skin.

In contrast, while the apocrine glands also release their secretions into hair follicles, they are more associated with sweat and specific body odor factors rather than the oily substances produced by sebaceous glands. Eccrine glands are sweat glands that primarily function to regulate body temperature through perspiration and do not secrete into hair follicles. Sudoriferous glands, which include both eccrine and apocrine glands, pertain to sweat production overall. However, it is the sebaceous glands specifically that are characterized by their small, sac-like structure and the secretion of oil into hair follicles.