Final answer:
Sebaceous glands are the ones that release an oily secretion called sebum into the hair follicles, which lubricates and protects the skin and hair.
Step-by-step explanation:
Glands that discharge an oily secretion into hair follicles are sebaceous glands. Sebaceous glands are exocrine glands found throughout the mammalian skin, with the exception of the palms of the hands and soles of the feet. These glands produce sebum, which is a thick, oily substance designed to lubricate the skin and hair, making them waterproof and preventing them from drying out. Additionally, sebum carries antibacterial properties that help to inhibit the growth of microorganisms on the skin.
Unlike sudoriferous glands which produce sweat to help with thermoregulation, sebaceous glands are primarily involved in maintaining the integrity and health of the skin and hair. In humans, these glands typically become more active during puberty due to hormonal stimulation