Exam 2 Review:  Chapter 5:  Skin Glands

sebaceous glands = skin oil glands - An epidermal derivative, the small subcutaneous exocrine glands, usually connected with hair follicles which secrete sebum, an oily semifluid material, composed in large part of lipids, which softens, prevents the drying of, and lubricates the hair and skin.

sebum - The oily semifluid secretion of the sebaceous glands, consisting chiefly of lipids, keratin, and cellular material; with perspiration it moistens and protects the skin.

sudoriferous glands = sweat glands - An epidermal derivative, the small convoluted tubular exocrine glands which are situated in the subcutaneous tissues and discharge by minute orifices onto the surface of the skin; the secretion is regulated by the autonomic nervous system; the sweat is a plasma filtrate which serves in thermoregulation through evaporative cooling and the salty, slightly acid residue left behind has mild antibacterial properties.

eccrine sweat glands - The predominant type of sweat gland found in the skin of most parts of the body, especially numerous on the palms, the soles of the feet and the forehead, play a major role in evaporative cooling (thermoregulation). [aka merocrine sweat glands]

apocrine sweat glands - The minority of sweat glands, with a distribution limited to axillary and anogenital regions; they have almost no role in thermoregulation, instead they begin functioning at puberty and secrete in response to sympathetic autonomic commands related to stress, e.g., anger or fear, or during sexual arousal.

mammary glands - An epidermal derivative, a pair of highly specialized sweat glands, located on the anterior thoracic wall, which secrete milk to nourish the newborn; these glands are regulated by estrogens, prolactin and oxytocin.

ceruminous glands - An epidermal derivative, highly specialized sweat glands, located in the external ear canal which produce a protective secretion, cerumen = earwax.

cerumen - The secretion of the ceruminous glands, a yellow or orange sticky, bitter, waxy substance which assists in protecting the external ear canal from invasion by ectoparasites (insects).

Sketch and label, etc.

3. the homeostatic feedback path regulation response by the skin to excessive alterations in body temperature.

    Why is this a negative feedback system?

Because there is an inverse relationship between environmental temperature and the adjustment made to alter the skin's, and therefore, the body's, temperature.  When the external environment gets hotter, the skin responds with its cooling mechanisms, sweating, which provides evaporative cooling, and the dermal capillary beds dilate, routing warm blood to the dermis where heat is radiated away, and the skin shows flushing ; when the external environment gets cooler, the skin responds with its warming mechanisms, dermal capillary beds constrict, routing warm blood to deeper tissues, and the skin shows pallor.  Other body systems contribute to the overall thermoregulation as shown in the figure above.