Osteoporosis is a disease where decreased bone strength increases the risk of a broken bone. It is the most common reason for a broken bone among people who are old. Bones that commonly break include the back bones, the bones of the forearm, and the hip.
In humans and other mammals, the anatomical features of the respiratory system include trachea, bronchi, bronchioles, lungs, and diaphragm.Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood.n humans and other mammals, the anatomical features of the respiratory system include trachea, bronchi, bronchioles, lungs, and diaphragm.
1 The upper respiratory tract includes the mouth, nose, throat, larynx (voice box), and trachea (windpipe). 2  Upper respiratory infections are often referred to as  colds 3  .. The lower respiratory tract includes the bronchial tubes and the lungs.4  Bronchitis and pneumonia are infections of the lower respiratory tract. The upper respiratory tract includes the mouth, nose, throat, larynx (voice box), and trachea (windpipe). 2  Upper respiratory infections are often referred to as  colds 3  .. The lower respiratory tract includes the bronchial tubes and the lungs.