Respiratory Physiology 1 Flashcards
What 4 parts can respiratory physiology be divided into?
-external respiration
-transport of gases by the blood
-internal respiration
-regulation of respiration
Movement of air into the lungs
Inspiration
Movement of air out of the lungs
Expiration
What causes air to move?
Pressure gradient
T/F
Air will always move from HIGH pressure to LOWER pressure as it moves down the pressure gradient
True
What is the standard atmospheric pressure?
760 mm HG
What happens when the standard atmospheric pressure is equal to the alveolar pressure?
No gas exchange occurs
(This happens between inspiration and expiration)
What produces inspiration?
The pressure within the alveoli of the lungs is lower than atmospheric pressure
What produces expiration?
The pressure in the alveoli of the lungs is higher than atmospheric pressure
PIP
Intrapleural pressure (intrathoracic)
PA
Alveolar pressure
PB
Barometric pressure (atmospheric)
For inspiration, alveolar pressure must be ___________ barometric pressure
Less than
<
For expiration, alveolar pressure must be __________ barometric pressure
Greater than
>
PA = PB
No exchange of gases
Why must PIP be less than PA
(PIP<PA)
To keep alveoli open
Contraction of the diaphragm and external intercostal muscles
Inspiration
When the lungs expand for inspiration, how is the pressure affected?
-decreased intrapleural pressure allowing lungs to expand
-decreased alveolar pressure, higher atmospheric pressure
T/F
Air moves into the lungs when alveolar pressure drops below atmospheric pressure
True
Ability of pulmonary tissues to stretch, thus making inspiration possible
Compliance
The volume of gas varies inversely with pressure at a constant temperature
Boyles Law of Gases
A passive process that begins when the inspiration muscles are relaxed, which decreases the size of the thorax
Expiration
What happens when the thoracic volume is decreased?
-intrapleural pressure increases
-alveolar pressure increases above atmospheric pressure
T/F
Air moves out of the lungs when alveolar pressure exceeds the atmospheric pressure
True
Why must the pressure between parietal and visceral pleura (interpleural pressure) always be less than alveolar and atmospheric pressure?
This must be negative to maintain inflation of the lungs
What is the difference between intrapleural pressure and alveolar pressure called?
Transpulmonary pressure
Tendency of pulmonary tissues to return to a smaller size after having been stretched out;occurs passively during expiration
Elastic recoil
What muscles contract during expiration?
Internal intercostal muscles
What muscles contract during inspiration?
External intercostal muscles, diaphragm
In which direction do the external intercostal muscles go?
Down (rib 1-rib 2)
In which direction do the internal intercostal muscles go?
Up (rib 2 - rib 1)
-pulmonary ventilation (breathing)
-pulmonary gas exchange between capillaries and alveoli
External respiration
-Systemic circulation
Transport of gases by the blood
-systemic tissue gas exchange between capillaries and body cells
-cellular respiration
Internal respiration
-centred on the brainstem
Regulation of respiration
