Which of the following is NOT an appendage of the skin?

• A. Sweat glands
• B. Hair
• C. Blood vessels
• D. Nails

Answer: (C)

Blood vessels are not considered appendages of the skin. Instead, they are part of the circulatory system that supplies nutrients and oxygen to the skin and regulates temperature. In contrast, sweat glands, hair, and nails are indeed appendages of the skin. These structures originate from the epidermis and are involved in various functions such as thermoregulation (sweat glands), protection and sensory detection (hair), and protection of the fingertips (nails). This classification helps to emphasize the unique roles that these appendages play in maintaining skin health and overall physiological function, differentiating them from the underlying vascular structures that support skin function.