Respiration * Flashcards
what is the thoracic cage composed of ?
sternum, ribs, costal cartilage and thoracic vertebrae
how do ribs join the sternum ?
on the anterior aspect via costal cartilage (also join the vertebrae on the posterior aspect via two joints)
what are two joints that articulate at posterior aspect between ribs and vertebrae ?
costotransverse and costovertebral joints
what are the three types of thoracic muscles ?
- external intercostals
- internal intercostals
- innermost intercostals
describe external intercostlas:
- elevates ribs (inspiration)
- super-lateral to inferomedial
- “hands in your pocket”
which thoracic muscle is used during inspiration ?
external intercostals
describe internal and innermost intercostals :
- depressed ribs (forced expiration)
- superomedial to inferolateral
- “grab your collarbones”
what happens to the diaphragm when contraction occurs ?
- lowers dome
- increases volume of thoracic cavity
which thoracic muscles are used during expiration ?
innermost and internal
what happens to volume when you are breathing in ?
increasing volume
what happens to volume when you are breathing out ?
decreasing volume
increasing volume =
inspiration
decreasing volume =
expiration
why are lungs under tension ?
- naturally want to collapse
- stuck to visceral pleura
alveolar pressure =
atmospheric pressure
what two layers does the pleura have that creates a sac ?
parietal and visceral layers
what is intrapleural pressure ?
around 4 mmHg below atmosphere
when the thoracic cage expands (muscle contraction) what does the parietal pleura do ?
the parietal pleura also contracts… screaming the intrapleural pressure
what is pneumothorax ?
puncture to pleural membrane causes air (pneumo) in pleural space (lung is deflated)
does the intrapleural space pressure change during pneumothorax ?
yes
in what case does the lung no longer go under tension + collapses ?
pneumothorax
if blood is involved in an pneumothorax what is this called ?
hemothorax
what happens if you reseal the hole during an pneumothorax ?
can shift the position of organs in the thorax which can be really problematic
how’s the pressure inside the alveoli during pneunothorax ?
same as atmospheric pressure under normal conditionse