Final answer:
With puberty, oil glands (sebaceous glands) and sweat glands (particularly apocrine glands) become more active. Sebaceous glands produce sebum, leading to possible acne, while apocrine glands are responsible for the body odor. The activity of these glands increases in response to the higher levels of sex hormones during adolescence.
Step-by-step explanation:
During puberty, several types of skin glands become more active. These include the oil glands and sweat glands. The oil glands, or sebaceous glands, produce an oily substance called sebum, which works to waterproof and lubricate the skin and hair. This change is especially pronounced due to the increased production of sex hormones, which stimulate the activities of these glands. The sebum can mix with dead skin cells and block hair follicles, leading to the commonly experienced pimples during adolescence.
The apocrine sweat glands, which are located in areas such as the armpits and groin, also become active during puberty. These glands produce a thicker, milky sweat that, when broken down by bacteria on the skin, can lead to the body odor associated with puberty. The eccrine sweat glands, which are involved in thermoregulation and are spread across the body, increase their activity as well, but they do not contribute as significantly to body odor as the apocrine glands. It is these changes in glandular activity, along with increased hormone levels, that lead to many of the secondary sexual characteristics observed during puberty, such as the growth of pubic and facial hair, deepening of the voice in males, and widening of hips in females.