What does the integumentary system consist of?

The integumentary system primarily consists of hair, skin, and nails, which serve as the body's first line of defense against external factors such as pathogens, chemicals, and physical damage. This system plays crucial roles in protection, regulation of temperature, and sensation.

Skin, the largest organ of the body, helps to protect against infection and desiccation while also playing a vital role in thermoregulation and sensory reception. Hair can help in regulating body temperature and provides a barrier to protect the scalp. Nails protect the distal phalanxes and enhance sensation.

The other options mention systems or components that do not pertain to the integumentary system. Muscles, bones, and joints are part of the musculoskeletal system, while glands, organs, and tissues refer to various systems such as the endocrine or digestive systems. Membranes, blood vessels, and nerves belong to the circulatory and nervous systems, highlighting the distinct functions and roles of each body system.