Your dog's throat anatomy is quite similar to yours. You're familiar with the anatomical terms trachea, larynx, epiglottis and esophagus -- your dog shares them and they function in much the same way as yours do. Your dog's throat anatomy begins with the pharynx, the passage lined with membranes between the nose and throat.
The trachea, or windpipe, is a tube consisting of flexible, C-shaped cartilage rings. A dorsal ligament connects with the cartilage rings, forming a tube. Air passes through the tube en route to the left and right bronchi, then on to the bronchioles, which are smaller airways in the lungs. Over time, these rings can weaken and flatten, leading to tracheal collapse. Occurring most often in small breeds, a honking cough, breathing problems and exercise intolerance are signs of tracheal collapse.
Your dog's voice box, or larynx, sits atop the trachea. It's the source of all his barking, growling, whining and other vocalizations. It serves along with the epiglottis as tracheal protection. The larynx consists of cartilage, muscles and ligaments. It's kept in place by the hyoid apparatus, which also supports the tongue and pharynx. Your dog's larynx is bordered on the sides and front by the thyroid gland, shaped like a shield. As in humans, inflammation of the larynx is known as laryngitis.
Your dog's epiglottis, on top of his larynx, acts as a gatekeeper. It prevents food from entering the larynx and the windpipe when the dog swallows. Shaped like a leaf, the epiglottis moves over the entrance to the larynx once swallowing commences.
The canine esophagus sits alongside the trachea, beginning as part of the pharynx. It's a tube that conveys foods from its initial point to the stomach, with virtually no absorption of eaten material. Sphincters on either end of the esophagus aid in getting food to its destination without harm to other parts of the throat anatomy. The top sphincter muscle keeps food heading into the esophagus and not the larynx, while the bottom sphincter muscle is the entrance to the stomach. Both muscles are closed whenever the dog isn't swallowing, to keep air from entering the digestive tract.