Breathing and Gas exchange

Inhalation process

The diaphragm contracts and moves down, the external intercostal muscles contract and that causes the ribs to move up and out, pressure decreases because the volume in the thorax increases, the air moves from from high pressure to low pressure and the air enters the lungs

Exhalation process

The diaphragm relaxes and moves up, the external intercostal muscles relax causing the ribs to move down and in, the pressure in the thorax increases as the volume decreases, the air rushes out from high pressure to low

The process of air entering your body

You breath in through the nose where the air is moistened and warmed, the air travels down the trachea to the lungs, tiny hairs called cilia help remove the dirt and microbes, the air enters bronchi which divide into bronchioles, at the end of bronchioles there are alveoli

The adaptions of alveoli

Thin walls, one cell thick, which means there is a short diffusion distance = fast exchange

Large surface area, a lot of respiration can happen at once = fast exchange

Large diffusion gradient, the oxygen concentration in the alveoli is higher then in the capillary so the oxygen moves there fast

Moist walls, gasses dissolve in the moisture