o Epipharynx: It extends from the base of the skull to the upper surface of the soft palateo Mesopharynx: reaches from the Uvula to the level of the hyoid bone.o Hypopharynx: it is the part of the throat that connects to the esophagus
The Alveoli are microscopic chambers at termini of bronchial tree. Walls of simple Squamous epithelium are underlain by thin basement membrane. External surface are intimately associated with pulmonary capillaries. Some Alveolar cells produce surfactant.
o The main function of the Alveoli is, it’s the main gas exchange.o The alveoli removes the carbon dioxide from the blood in the capillaries and exchange it with oxygen to be taken to other parts of the body. The carbon dioxide is taken out of the body when we exhale.
The Lungs are paired composite organs that flank mediastinum in thorax. The lungs are composed primarily of alveoli and respiratory passageways. Stroma is fibrous elastic connective tissues, allowing lungs to recoil passively during expiration.
Major Functions of the Respiratory System Pulmonary Ventilation: External Respiration: Movement of air into and out Movement of oxygen fromof the lungs so that the gases the lungs to the blood andthere are continuously of carbon dioxide from thechanged and refreshed blood to the lungs(Breathing) Transport of respiratory gases: Internal respiration:Is the process of distributing the Movement of oxygen from bloodoxygen throughout the body to the tissue cells and of carbonand collecting CO2 and dioxide from tissues cells to bloodreturning it to the lungs.