explain the role of the ribsand the diaphragm in the breathi

Movement of air from the external environment into the lungs is accomplished by the action of two groups of muscles。The first is the diaphragm,a muscular wall that divides the trunk's body cavity into two parts,the chest and the abdomen。The second consists of the rib muscles (intercostal muscles)。These muscles act together to change the size of the chest cavity。The rib muscles are attached to your ribs,which in turn encircle the lungs and chest cavity。Together,this system is often referred to as the rib cage。