Describe the mechanism of breathing in human? for 5 marks
Answers
Mechanics of Breathing. The action of breathing in and out is due to changes of pressure within the thorax, in comparison with the outside. This action is also known as external respiration. When we inhale the intercostal muscles (between the ribs) and diaphragm contract to expand the chest cavity.
When we inhale air,it passes through our nostrils into the nasal cavity. from the nasal cavity,the air reaches our lungs through the wind pipe.lungs are present in the chest cavity.this cavity is sorrounded by ribs.a large muscular sheet called diaphram forms the floor of the chest cavity.breathing involves the movement of the diaphram and the rib cage.during inhalation,ribs moves up and outwards and diaphram moves down.this movement increases space in our chest cavity and air rushes into the lungs.the lungs get filled with air.during exhalation,ribs move down and inwards while diaphram moves up to its former position.this redues the size of the chest cavity and air is pushed out of the lungs.