Breathing Flashcards
What two sets of muscles bring about the pressure changed within the lungs?
- The diaphragm
- The intercostal muscles
Which intercostal muscles contract during inspiring?
External intercostal muscles
Which intercostal muscles cause expiration?
The internal intercostal muscles
What do the ribs do when inspiring?
They are pulled upwards and outwards which increases the volume of the thorax
When inspiring, what does the increased volume of the thorax cause?
Reduces the pressure in the lungs
What do the ribs do during expiration?
They are moved downwards and inwards which decreases the volume of the thorax
What do the diaphragm muscles do during expiration?
They relax so it is pushed up by the contents of the abdomen that were compressed during inspiration ( volume of thorax further decreases)
What happens to the pressure in the lungs during expiration?
It increases
What is the pulmonary ventilation rate?
How much air is taken in and out of the lungs per minute (dm3 / min)
What ensures a constant supply of oxygen to the body?
A maintained diffusion gradient at the alveolar surface
What 3 features enable efficient transfer of materials?
1) thin exchange surfaces
2) partially permeable
3) large surface area
What does there need to be a movement of (2) to maintain a diffusion gradient?
- Environmental medium E.G air
- Internal medium E.G blood
Why are the alveoli located inside the mammal?
They are thin so easily damaged
Why does ventilating occur?
As diffusion alone is not fast enough to maintain an adequate transfer of oxygen and carbon dioxide through the lungs - acts as a form of mass transport
How thick are capillaries?
One cell thick
