Week 3 - Respiration Flashcards
Explain the path of gases take from the alveolar fluid to the pulmonary capillary endothelium
Alveolar fluid, Alveolar epithelium, basement membrane of alveolar epithelium, interstitial space, basement membrane of capillary endothelium, pulmonary capillary endotheium
Specialized characteristics of alveoli to allow
for gas exchange (4)
Large surface area in relation to volume
Very thin-walled, elastic
Fluid-lined to allow for gases to dissolve
Highly vascularised structures
Pulmonary blood flow from start to finish
Pulmonary artery, arteriole, capilary, pulmonary venule, vein
Control of pulmonary ventilation
Peripheral chemoreceptors - Aortic and carotid bodies are sensitive to changes in O2, PCO2 and H+. Overall PCO2 is the strongest stimulus to
respiration
Mechanoreceptors in the lungs prevent the lungs from over inflating
Proprioceptive reflexes - during exercise muscles and joints tell the brain to increase ventilation
Temperature: minor affect on ventilation
Do gases move from a low to high pressure
No, unless assisted
Boyle’s Law on pressure and volume
The pressure of gas is inversely related to volume.
If volume increases, pressure decreases and vice versa
3 pressures to do with respiration
Barometric pressure (atmosphere),
Intra-alveolar pressure (within alveoli)
Intra-pulmonary pressure (pressure within the lung)
At the end of expiration what is the atmospheric pressure and alveolar pressure
The same
What does the diaphragm do during inspiration
Moves downwards increasing the superior, inferior dimension of the thoracic cavity
What do the muscles of inspiration do
Increase the anterior-posterior dimension of the thoracic cavity
For inspiration to occur, what does the intra-alveolar pressure have to be in the lungs
Lower than atmospheric pressure
Expiration occurs by
Passive process when lung tissue recoils, inspiration muscles relax and diaphragm relaxes
What is Tidal Volume
Volume inspired or expired per breath
Maximum inspiration at end of tidal inspiration
Inspiratory Reserve Volume (IRV)
Mnemonic for lung volumes and capacities (6 LITERs)
Lung capacity (TLC = 6L), Inspiratory reserve volume (IRV = 3.3 L) + Tidal volume (TV = 0.5 L) + Expiratory reserve volume (ERV = 1 L) + Reserve volume (RV = 1.2 L)
