"Keratinized" refers to a process where cells produce a tough, protective protein called keratin. This protein is essential for forming the outer layer of skin, hair, and nails, providing strength and resilience against environmental damage. In the human body, keratinized tissues are found in areas exposed to friction and abrasion, such as the palms of the hands and soles of the feet. This adaptation helps to prevent injury and water loss, ensuring that these areas remain durable and functional in daily activities.