The tracheal gland is an important part of the human respiratory system. Located on the wall of the trachea, it has several functions. One of the main tasks of the tracheal glands is to humidify the air entering the lungs. Gastric glands are enzymes that take part in the processes of food digestion and metabolism. Muscarinic glands, also located in the trachea, help regulate the functioning of the respiratory muscles.