lecture 16 - anatomy of the thorax and breathing Flashcards
what is the mediastinum region
the heart, vessels + pericardium
what are the anterior and posterior boundaries of the thorax
the sternum and the vertebrae
what are the superior and inferior boundaries of the thorax
the base of the neck and the diaphragm
what is the pleural cavity
the space between the pleura
what is the function of parietal pleura
- slippery surface for frictionless movement against other structues
- fluid bond causes lungs to ‘stick’ to thoracic wall
where is the parietal pleura
on the outer
where is the visceral pleura
directly on the lungs
what is the diaphragm
sheet of skeletal muscle
what does the diaphragm seperate
the thorax from abdomen
when is the diaphragm dome shaped
when it is relaxed
when is the diaphragm flattened
when contracted
what does contraction of the diaphragm cause
expansion of the thoracic cavity and compression of the abdominopelvic cavity
where do intercostal muscles attach
attach diagonally between neighbouring ribs
what do the external intercostal muscles do
lift ribcage and expand cavity
- inspiration = quiet and forced
what do the internal intercostal muscles do
depress ribcage and decrease cavity
- expiration = forced only
what are the accessory muscles of the thorax
several muscles that attach to the thoracic cage
what are the functions of the accessory muscles
- some increase cavity volume for forced inspiration
- others decrease cavity volume for forced expiration
how is pressure related to volume in the lungs and what does this mean during inspiration and expiration
- pressure inversely related to volume
inspiration = volume increases
expiration = volume decreases
what needs to be established in order for us to be able to breathe
a pressure gradient
what is the pressure like in the lungs between breaths
pressure inside the cavity = pressure outside
- no gradient
what occurs in the lungs when there is an increase in volume
decrease in pressure, therefore air flows in
what occurs in the lungs when there is an decreases in volume
increase in pressure, therefore air flows out
what connects the sternum to the ribs
costal cartilage
what is sternocostal cartilage and what type of joint is there
against the sternum = synovial joint
what is the costochondral cartilage and what type of joint is here
against the ribs = cartilaginous
what is the interchondral cartilage and what type of joint is here
connects interchondral joints which are below the sternum = synovial
what are the prosterior thoracic joints
the costotransverse and the costovertebral joints
what does the costotransverse joint connects
between rib and transverse process of vertebrae
what does the costovertebral joint connect
between rib and body of vertebrae
what are the muscles that are used during ‘quiet inspiration’
diaphragm contracts = flattens
external intercostals contract = lifts ribs
what are the muscles that are used during ‘forced’ inspiration
diaphragm contracts = flattens
external intercostals contract = lifts ribs
accessory muscles contract = to further expand the thoracic cavity
what are the muscles that are used during normal ‘quiet’ expiration
diaphragm relaxes = dome shaped
external intercostals relax = ribs no longer lifted
what are the muscles that are used during ‘forced’ expiration
diaphragm relaxes = dome shaped
external intercostals relax = ribs no longer lifted
accessory muscles contract to further decrease cavity
what is the lung tissue like
elastic = always trying to recoil
what pleura is on the lungs
visceral pleura
what pleura is on the thoracic wall
parietal pleura
what is the function of the pleural fluid in between lungs and thoracic wall
slippery surface for frictionless movement
fluid bonds causes lungs to stick to thoracic wall
