摘要：AbstractHuman respiration is a process that always occurs in all living things including humans. However, the process is abstract and difficult to observe by most people, including high school students. Simulation is one way to explain respiration and it can be used as a medium of learning for the students. Respiratory process consists of inspiration and expiration. The inspiration is the process of oxygen entry from the environment into the lungs (alveolus) and expiration is the process of carbon dioxide exit from the lungs (alveoli) into the environment. The respiratory mechanism includes the changes of air volume in the lungs and the frequency of human breathing. The changes of the air volume and the respiratory frequency depend on physical factors such as gender, type of activity, age, weight, and height of humans. These physical factors may be treated as input variables that affect the changes of the air volume and the breathing frequency. In this paper, a model of lung volume and breathing frequency are developed for human respiratory simulation. The model is a modified model of proposed models in the literatures. In the model of lung volume and breathing frequency, the following factors are considered, i.e. tidal volume (VT), functional residual capacity (FRC), total lungs capacity (TLC), inspiratory volume (VI) and expiratory volume (VE). The model of lungs volume is then used to visualize the process of expansion and contraction of the lungs. Meanwhile, the model of breathing frequency is used to visualize the duration of the expansion and contraction of the lungs. Breathing period (T) is a time taken for a single breathing that consists of the time for inspiration and expiration. These inspiration and expiration times may be modified and adapted to model of various physical conditions and needs of the humans.
