What structure is specifically designed to protect underlying tissues in the vestibule?

The correct answer is vibrissae (guard hairs). These structures are specialized hairs located in the vestibule of the nasal cavity. Their primary function is to act as a physical barrier, trapping larger particles, dust, and debris from entering deeper into the respiratory system. By doing so, vibrissae protect the underlying tissues by preventing potential irritants and pathogens from inhaling and causing harm to the sensitive mucosal surfaces and respiratory tissues.

Goblet cells, while important for producing mucus, do not specifically provide a protective physical barrier like vibrissae. Conchae (nasal turbinates) play a role in increasing the surface area of the nasal cavity for warming and humidifying air but do not provide direct protection in the manner that vibrissae do. Respiratory epithelium is crucial for overall respiratory function, including mucous secretion and trapping particles, but it is the vibrissae that serve the direct purpose of protecting the vestibule by physically blocking debris.