The model on test is the 'Sprinter Stick which according to the website is designed to be a 'segmental stretching device' and is the most rigid of the smaller models. The rigidity is still allows some flex without too much pressure and the stick certainly feels strong enough to take a hard rub if needs be.
In most vertebrates oxygen enters the bloodstream  via diffusion at the alveoli of the lungs. This diffusion (a  passive thing) is accomplished because oxygen concentration â¦ in the  lungs is much higher than that of the blood, even than that of   oxygenated blood.es, in a sense the respiratory system removes oxygen from the air and replaces it with carbon dioxide. When the respiratory system takes in air, it reduces the concentration â¦ of oxygen from 21% to 16%. The air is inhaled by the diaphragm into the trachea, which leads into the lungs via the bronchi.
The alveoli in the lungs are coated with a moist film that dissolves air in the lungs. Oxygen diffuses across the thin epithelium of the alveoli sacs into the blood within the surrounding capillaries. Carbon dioxide also diffuses from the blood in the capillaries to the alveoli air sacs.The now oxygen rich blood is returned to the heart via the pulmonary veins. Carbon dioxide is expelled from the lungs by exhalation.Air is supplied to the lungs through the process of breathing. The diaphragm plays a key role in breathing. The diaphragm is a muscular partition that separates the chest cavity from the abdominal cavity.xygen diffuses across the thin epithelium of the alveoli sacs into the blood within the surrounding capillaries. Carbon dioxide also diffuses from the blood in the capillaries to the alveoli air sacs.