Trachea are generally highly elastic but they may calcify with age. The trachealis muscle connects the ends of the incomplete rings and contracts during coughing, reducing the size of the lumen of the trachea to increase the rate of air flow. The esophagus lies posteriorly to the trachea, adjoining along the tracheoesophageal stripe. Circular horizontal bands of fibrous tissue called the annular ligaments of trachea join the tracheal rings together. The cartilaginous rings are incomplete to allow the trachea to collapse slightly so that food can pass down the esophagus. A flap-like epiglottis closes the opening to the larynx during swallowing
History of beliefs about the human body Yang Qi energy where as a female has dominant Yin energy. Transgenderism, hermaphroditism and other variations of the body can be explained by the Yin and Yang Qi ideas of the body much better than the European counterparts. Other types of change in the world were classified by Wood, Fire, Earth, Metal and Water. Applied to the body these 5 forces were the Liver, Heart, Spleen, Lung, and Kidney. These representations of the physical world in the body was understood dynamically and represents a deeper connection to the non animate objects and surroundings of a human. The body was not