Thorax and Breathing Flashcards
what vertebrae is the position of the thorax at?
T1-T12
what is the thorax composed of?
rib cage, muscles, sternum, heart, lungs, pleura, blood vessels, nerves
what is the central portion of the thorax?
mediastinum
which ribs are true ribs and why?
1-7 because they join straight onto costal cartilage
which ribs are false ribs and why?
8-10 as they join onto common cartilage and then costal cartilage
which ribs are floating ribs?
11-12
what nerve controls the diaphragm?
phrenic nerve
what does the diaphragm close?
the inferior thoracic aperture
what is the pleural cavity?
the chest cavity
why is the medial surface slightly concave?
allows for other viscera to fit in thorax
where do the primary bronchi and blood vessels enter the lungs?
at the hilum
what is the hilum?
a gateway for all the blood vessels and nerves to enter and leave
whereabouts is the apex of the lung?
above the clavicle
why is there only 2 lobes on the left lung but 3 on the right?
the heart sits on the left hand side
what are the lungs separated by?
oblique fissures in the left lung and oblique and horizontal fissures in the right lung
what do fissures in the lungs do?
increase the surface area
what are the parts of the right lung?
oblique fissure, superior lobe, middle lobe, inferior lobe, horizontal fissure
where does the pulmonary artery sit on the left lung?
towards the top
what is the costal border?
where the lungs join to the ribs at the front
what is the posterior border?
where the lungs join to the ribs at the back
what does the parietal pleura do?
lines the whole of the thoracic cavity, adheres to internal surface of the ribs and superior face of the diaphragm, partitions off the mediastinum
what does the visceral pleura do?
lies against the parietal pleura and covers the outer surface of the lung
what does pleural fluid do?
ensures there is no friction between the two layers
where is the pleural fluid?
in the space between the parietal and visceral pleura
what is a costodiaphragmatic recess?
a space at the bottom where fluid can collect
what do internal intercostal muscles do?
depress ribs
what do external intercostal muscles do?
elevate ribs
what is the function of the diaphragm?
to enlarge the thorax as it contracts and moves downwards
what does the quadratus lumborum do?
depresses the last rib
posteriorly, where do the blood vessels of the thorax come from?
aorta
anteriorly, where do the blood vessels of the thorax come from?
internal thoracic artery
what is the venous supply to the thorax?
intercostal vein
what is the arterial supply to the thorax?
intercostal artery
what is the nerve that supplies the thorax?
intercostal nerve
why does the aorta not go through the diaphragm?
so it is not squished during contractions
name the accessory muscles used in respiration
sternocleidomastoid, scalene muscles, pectoralis major
what does the sternocleidomastoid do if it is needed in respiration?
raise the clavicle in forced inspiration
what does the scalene muscles do if they are needed in respiration?
raise the first rib in forced inspiration
what does the pectoralis major do if it is needed in respiration?
widen the thorax in forced inspiration
when are the accessory muscles used?
when people have chronic respiratory problems
what does contraction of the diaphragm produce?
quiet inspiration
where are external intercostal muscles used?
in forced inspiration e.g. illness/sport
what does the diaphragm do during quiet inspiration?
it moves downwards increasing the capacity of the thoracic cavity
what do the inspiratory muscles do during expiration?
relax causing a decrease in size of the thorax
what does the diaphragm do during expiration?
moves upwards
what do the internal intercostal muscles do during expiration?
move the ribcage downwards
what do the ribs do during inspiration?
swing forwards and upwards to increase the chest capacity front to back
what is the blood air barrier composed of?
capillary endothelium-basement membrane. interstitial space (varies), basement membrane of alveolus, alveolar epithelium
