3 - Pulmonary function Flashcards
Explain inspiration at rest
Lower pressure in lungs Diaphragm contracts & flattens Intercostal muscles contract. Rib cage lifts up and out. Increase thoracic cavity. Active process
Explain expiration at rest
Passive process External intercostal muscles relax. Diaphragm relaxes and returns dome shaped. Ribs come in and down. Thoracic cavity decreases. Pressure increases
Explain inspiration in exercise
Sternocleidomastoid contracts to lift the sternum. The scalene and pectoralis minor lift the ribs further. Thoracic cavity increases
Explain expiration in exercise
More active Internal intercostal muscles contract to pull the rib cage in and down. Abdominals contract to push the diaphragm up. Rapid reduction of the thoracic cavity
What is tidal volume
The amount of air breathed in or out per breath
What is inspiratory reserve volume?
Max amount of air that is forcibly inspired in addition to tidal volume
Explain expiratory reserve volume
Max amount of air that can be forcibly expired in addition to tidal volume
What is vital capacity?
Max amount of air exhaled after a max inspiration
What is residual volume?
The amount of air left in the lungs after maximal expiration
What is total lung capacity?
Vital capacity plus residual volume
What is minute ventilation?
The amount of air moved in and out of the lungs in one minute
How do you calculate minute ventilation?
Frequency of breathing x tidal volume
How do you calculate vital capacity?
Tidal volume + inspiratory reserve volume + expiratory reserve volume
How to calculate total lung capacity?
Tidal volume + inspiratory reserve volume + expiratory reserve volume + residual volume
Where does gaseous exchange happen?
Alveoli and muscle site
Explain why gaseous exchange happens?
The partial pressure/concentration of oxygen and carbon dioxide difference The partial pressures want to be equal
State and describe the process of how gases move through the lungs and capillaries
Diffusion - The movement of gas molecules from an area of high concentration/partial pressure to a low area of concentration/ partial pressure
What makes diffusion efficient
Permeable of the alveoli and capillary walls Short distance Readiness of haemoglobin to combine with oxygen Large surface area of alveoli Slow movement of blood through capillaries
What controlled the rate and depth of breathing and where is it?
Respiratory centre Medulla oblongata
What are the chemical changes that cause a change in breathing depth and rate during exercise?
Increase in carbon dioxide Increase in lactic acid
How is carbon dioxide transported and what %
5% in blood plasma 20% combined with haemoglobin 60-80% combines with water to make bicarbonate.
What detects changes in blood acidity
Chemoreceptors
What detects change in blood pressure
Baroreceptors
Describe how the body increases breathing rate and depth
Chemoreceptors detect a higher blood acidity, meaning there’s more carbon dioxide in the blood, a message is sent to the medulla oblongata and the respiratory centre, the message is sent down the sympathetic nerve back to the diaphragm and intercostal muscles to contract
