2) Ventilation And Gas Exchange Flashcards
How do most living organisms gain their energy from?
Aerobic respiration
What does aerobic respiration produce?
ATP
What is the structure of the pleural membrane?
1 pleural membrane lines the rib cage and the other lines the outside of the lungs, the space between is filled with fluid.
What is the purpose of the pleural membranes and fluid
Provide protection and lubrication, allowing lungs to expand and contact easily without being damaged by other organs
What are the features of the gas exchange system?
Very large surface area
Very thin gas exchange surface
Good blood supply
What are the steps of inspiration?
1) Diaphragm contracts and moves down to become flat
2)If more O required, e.g. when exercising external intercostals contract and move rib cage downwards and outwards
3) Volume of thoracic cavity (chest) increases
4) Pressure decreases in lungs compared to outside
5) Air rushes in
What are the steps for expiration?
The elastic fibres in the alveoli shrink, increase pressure and air is squeezed out
1)When we are exercising, internal intercostals contract and move rib cage inwards and outwards
2)Abdominal muscles contract and the stomach and liver push diaphragm back so its domed again
3) Volume of thoracic cavity (chest) decreases
4) Pressure increases
5)Air rushes out
What is a mechanical ventilator?
A type ventilator that usually requires power and are controlled by a computer
When are mechanical ventilators used?
When a person is not able to ventilate their lungs themselves (breathe), they are assisted by using a mechanical ventilator.
How does a mechanical ventilator work?
Air is pumped into the trachea through an endotracheal tube (through mouth)/ tracheostomy tube (through skin into trachea)
This increases the pressure allowing air to flow into the airways until the end of the ventilator breath.
The pressure then drops to zero.
The chest and lungs contract and push the air in the lungs out through passive expiration
What would occur if the lung is punctured?
There would be a hole in the thoracic cavity, air would enter the thoracic chamber and increase the pressure outside the lungs.
The pressure also increases inside the lung, this means air no longer flows in and out.
What is a spirometer?
A device used to measure different aspects of how lungs are working.
How does a spirometer work?
A person using a spirometer breathes in and out of an airtight chamber, causing it to move up and down.
These movements can be recorded on a revolving drum or to a computer
What is the purpose of soda lime in a spirometer?
Soda lime absorbs CO2 so the person’s use of oxygen causes the trace to slop downwards from left to right
What is tidal volume?
Normal breathing volume, about 0.5dm³
