The lungs Flashcards
January exam
What are the structures of the lungs (there are 8 main ones)?
Nasal cavity and the mouth, trachea, lungs, alveoli, diaphragm, intercostal muscles, oesophagus.
What is the gas exchange system?
In the alveoli there is a high concentration of oxygen and a low concentration of carbon dioxide.
What happens during the has exchange?
Oxygen dissolves in the layer of moisture it can diffuse through the cell membrane. in the blood there is a low concentration of oxygen so the oxygen diffuses into the blood. the blood has a high concentration of carbon dioxide so diffuses from the blood into the alveoli.
What are the three main factors for the gas exchange?
very large surface area, very thin gas exchange surface (the walls are one cell thick) and a good blood supply- this maintains the concentration gradient.
What happens to the chest when you breath out?
The chest expands, the ribs move up and the diaphragm contracts and moves down.
What happens to the chest when you breath in?
The chest contracts, the lungs move up and the diaphragm relaxes moving up.
What happens during inspiration?
The diaphragm contracts and moves down to become flat. more oxygen is required- the intercostal muscles contracts and they move the rib cage upwards and outwards. the volume of the thoractic cavity increases. the pressure decreases in the lungs and air rushes in.
What happens during exspiration?
The elastic fibres in the alveoli shrink which increases the pressure and the air is squeezed out. The intercostal muscles contract and move the rib cage inwards and downwards. Abdominal muscles contract and the stomach and liver is push the diaphragm back. the volume of thoractic cavity decreases, the pressure increases and the air rushes in.
