respiration Flashcards
(146 cards)
in order for air to pass in and out of our lungs there needs to be a change in what
their needs to be a change in pressure
during inspiration, what opens to expands
during inspiration the thorax opens
during inspiration the thorax expands, does the traulmonary pressure, rise, stay the same as the atmospheric pressure or fall below the atmospheric pressure.
during inspiration, the intrapulmonary pressure falls below atmospheric pressure
because intrapulmonary pressure is now less than atmospheric pressure, air will naturally enter our lungs until what
air will naturally enter are lungs until the pressure difference no longer exists
what two laws explain the process of inspiration
boyles law and Daltons law
what does boyles law state
boyles law states that at a fixed temperature the amount of pressure exerted by a given mass of gas is inversely proportional to the size of its container.
in smaller volumes the gas molecules are more likely to collide with the walls of the container and exert a greater or lesser pressure as a result?
greater pressure will be exercted
larger volumes provide a greater space for the circulation of gas molecules, therefore ? pressure is exerted
less pressure is exerted
what is daltons law
Daltons law explains that in a mixture of gases each gas exerts its own individual pressure proportional to its size.
oon inhalation, the thorax expands and intrapulmonary pressure falls, why is this?
this is because air flows from areas of high to low pressure, air enters the lungs
what are the major muscles of inspiration
the diaphragm and external intercostal muscles.
where is the diaphragm found
it is found beneath the lungs at the base of the thorax
how many external intercostal muscles are there and where do they sit in the lungs
there are 11 external intercostal muscles, which sit in the intercostal spaces, these are the spaces between the ribs
during inspiration the diaphragm contracts downwards, pulling the lungs with it. simultaneously, what do the external intercostal muscles do
when the diaphragm contracts downwards, the external intercostal muscles pull the rib cage outwards and upwards.
when the diaphragm contracts and the external intercostal muscles pull the ribcage up and out, does this make the thorax bigger or smaller than before and how has this affected the atmospheric pressure
the thorax is now bigger than before and the intrapulmonary pressure is reduced below atmospheric pressure as a result
during expiration, do the external intercostal muscles and diaphragm relax or contract
during expiration, the external intercostal muscles and diaphragm relax
when the external intercostal muscles and diaphragm relax, what does this allow for
this allows the natural elastic recoil of the lung tissue to spring back to into shape, forcing air back into the atmosphere
what are the accessory muscles and why are they called this
the accessory muscles include the abdominal wall muscles, internal intercostal muscles, the sternocleidomastoids, the scalene and the pectorals. they are referred to as accessory muscles as they are rarely used for normal, quite breathing. e.g when blowing out candles you would use the accessory muscles
during inspiration respiratory muscles must overcome various factors that hinder thoracic expansions, what are these factors
- the natural elastic recoil of lung tissue
- the resistance to airflow through narrow airways
- the surface tension forces at the liquid-air interface in the lobule
the energy required by the respiratory muscles to overcome factors hindering thoracic expansions in referred to as what
the work of breathing
the amount of energy used up is kept to a minimum in the work of breathing due to what
due to lung compliance which is the ease with which lungs can be stretched
what is surfactant and how does is aide lung compliance
whenever a liquid and gas come into close contact with one another surface tension is generated.
Surfactant reduces the surface tension that occurs where the alveoli meet pulmonary capillary blood flow in the lobule, thereby reducing the amount of energy required to inflate the alveoli
where is surfactant manufactured
by the type II alveolar cells, found in the alveoli
why does the work of breathing also require overcoming airway resistance
as air flows through the bronchial tree, resistance to airflow occurs as the gas molecules begin to collide with one another in the increasingly narrow airways