Breathing Mechanics Flashcards
(31 cards)
what’s the first stage of inspiration?
the intercostal muscles contract, lifting the ribs upwards and outwards causing the chest to expand
what’s the second stage of inspiration?
the diaphragm contacts. It pulls down and flattens out the floor of the rib cage
what’s the third stage of inspiration?
the lungs increase in size as the chest expands
what’s the fourth stage of inspiration?
the pressure inside the lungs falls as they expand. the higher pressure of air outside means air is now sucked into the lungs through the nose and mouth.
what’s the first stage of expiration?
the intercostal muscles relax. the ribs move downwards and inwards under their own weight. the chest gets smaller.
what’s the second stage of expiration?
the diaphragm relaxes. it’s pushed back into the domed position by the organs underneath it.
what’s the third stage of expration?
the lungs decrease in size as the chest gets smaller. they are squeezed by the ribs and diaphragm.
what’s the fourth stage of expiration?
the pressure inside the lungs increases as they get smaller. the air pressure outside is now lower than it is in the lungs. air is forced out of the lungs through the nose and mouth
why can the lungs expand more during inspiration?
due to the use of the diaphragm and assisted by the external intercostal muscles.
What are the additional inspiratory muscles?
sternocleidomastoid
pectoralis major
what happens to expiration during exercise?
it’s a more active process and additional support is needed to force the lungs to expire more quickly
what are the additional expiratory muscles?
internal intercostals
rectus abdominis
What does the inspiratory centre in the Respiratory Control Centre do?
sends out impulses vie the phrenic nerve to the inspiratory muscles
What does the expiratory centre in the Respiratory Control Centre do?
stimulates the expiratory muscles during exercise, when stretch receptors detect changes in the rate and depth of breathing.
what do the chemoreceptors detect?
a change in pH as blood acidity increases as a result of blood plasms=a concentration of CO2 and lactic acid production
what do baroreceptors detect?
increase in blood pressure
what do proprioreceptors detect?
detect the movement in muscles and joints
How do the gases move during gaseous exchange?
from high pressure to low pressure
what does partial pressure explain?
the movement of gases within the body
what does systemic mean?
to the body
what happens with oxygen during internal respiration?
O2 diffuses from the systemic capillaries into cells
what happens with carbon dioxide during internal respiration?
CO2 diffuses from cells into systemic capillaries
why does internal respiration occur?
available surface area, which varies in different tissues
partial pressure gradient
rate of blood flow varies
What happens with oxygen during external respiration?
O2 diffuses from alveoli into pulmonary capillaries
