The Mechanism Of Breathing Flashcards
What is the process of breathing also known as?
Ventilation
What is ventilation?
The movement of air in and out of the lungs.
What happens when the air pressure of the atmosphere is greater than the air pressure of the lungs?
Air is forced into the lungs.
What is inspiration?
Inhalation
When does expiration occur?
When the air pressure in the lungs is greater than the air pressure in the atmosphere. This forces air out of the lungs.
What is expiration?
Exhalation
What 3 muscles bring about pressure changes in the lungs?
Diaphragm
Internal intercostal muscles
External intercostal muscles
What is the diaphragm?
This is a sheet of muscle that separates the thorax form the abdomen.
What does the diaphragm separate?
The thorax from the abdomen.
Where do the intercostal muscles lie?
Between the ribs.
The contraction of which intercostal muscles leads to expiration?
The internal intercostal muscles.
The contraction of which intercostal muscles leads to inspiration?
The external intercostal muscles.
Is breathing in a passive or active process?
It is active.
What happens to the internal intercostal muscles during inspiration?
They relax
What happens to the external intercostal muscles during inspiration?
They contract.
What happens to the volume of the thorax in inspiration?
It increases.
What causes the volume of the thorax to increase in inspiration?
The ribs are moved upwards and outwards.
The diaphragm contracts.
What happens to the diaphragm when it contracts in inspiration?
It flattens.
What does the increased volume in the thorax lead to?
A reduction of pressure in the lungs. This means that the atmospheric pressure is higher than the pulmonary pressure so air is forced into the lungs.
Is expiration an active or passive process?
It is largely passive.
What happens to the internal intercostal muscles when expiration occurs?
They contract.
What happens to the external intercostal muscles during expiration?
They relax.
What do the ribs do during expiration?
They move downwards and inwards.
What decreases the volume in the thorax?
The movement of the ribs.
The relaxing of the diaphragm.
What happens to the diaphragm during expiration?
The diaphragm muscles relax and so it is pushed up again by the contents of the abdomen that were compressed during inspiration.
What does the decreased volume in the thorax do to the lungs?
It increases the pressure so air is forced out.
What is the main cause of air being forced out during normal breathing?
The recoil of the elastic tissue.
What is the pulmonary ventilation rate?
This is the total volume of air that is moved into the lungs during 1 minute.
What is the tidal volume?
This is the volume of air that is normally taken in at each breath when the body is at rest.
What is the breathing rate?
The number of breaths that is taken in 1 minute.
What are the units of pulmonary ventilation rate?
dm^3min^-1
What are the units for tidal volume?
dm3
What are the units for breathing rate?
Min^-1
What is the equation for pulmonary ventilation rate?
Tidal volume X breathing rate.
