The Lungs and Gas Exchange

• lungs are in the thorax(top part of your body)
• lungs are like big sponges and are protected by the ribcage. surrounded by pleural membranes
• air that you breathe in goes through the trachea. this splits into 2 tubes called bronchi, one going to each lung
• bronchi split into progressively smaller tubes called bronchioles, which carry air to the alveoli, where gas exchange takes place
• gas exchange in body

  1.lungs contain millions of little air sacs called 'AVEOLI', surrounded by a network of blood capillaries, this is where gas exchange happens
• gas exhange in body

  2.blood passing next to aveoli has just returned to the lungs from the rest of the body, so it contains lots of carbon dioxide and very little oxygen, Oxygen diffuses out of the aveolus (high concentation) into the blood (low concentration). carbon dioxide diffuses out of the blood (high concentration) into the aveolus (low concentration) to be breathed out
• gas exhange in body

  3.when the blood reaches the body cells, oxygen is released frm the red blood cells (where theres a high concentation) and diffuses into the body cells (where the concentration is low)
• gas exchange in body

  4. at the same time carbon dioxide diffuses out of the body cells (where theres a high concentration) into the blood (when theres low concentration). its then carried back to the lungs