lungs, pleura and ventilation Flashcards
diaphragm: describe the attachments and relations of the diaphragm and the structures that pass through and behind it; explain the movements of the diaphragm, its motor and sensory innervation and pleural and peritoneal coverings
what does the lung base rest on
convex surface of diaphragm
what does the diaphragm separate from right lung
right lobe of liver
what does the diaphragm separate from left lung
left lobe of liver, stomach, spleen
how can the capacity of the thoracic cavity be increased
movements of diaphragm, movements of ribs
what is the main inspiratory muscle
diaphragm
diaphragm mechanism of breathing
contraction causes it to press on abdominal viscera which initially descend → further descent stopped by abdominal viscera, so more diaphragm contraction raises costal margin → increased thoracic capacity produced by diaphragm and rib movements in inspiration, reduces intraplueral pressure, with entry of air and expansion of lungs
3 components of thoracic surface of diaphragm
skeletal muscle from costal margin, sheet-like central tendon (section in between contracts), pericardial sac
what 4 things is the margin of the diaphragm connected to
costal margin, xiphoid process, ends of ribs 11 and 12, lumbar verterbrae
what does the diaphragm, pleura and lung cover and why
high abdominal organs such as liver as dome of diaphragm bulges high inside rib cage despite connection to costal margin
why do internal and external intercostal muscles stiffen rib cage
increase efficiency of diaphragm
what is the costal margin
attachment of ribs to diaphragm
what does the diaphragm consist of
flat central tendon with muscle radiating to costal margin (anteriorly) and crus (posteriorly) and vertebrae
diaphragm: first stage of insipiration
dome flattens to inrease vertical diameter of chest
diaphragm: second stage of insipiration
pulls costal margin up to increase transverse and antero-posterior diameters
where does the oesophagus extend from and to
from pharynx to diaphragm at level T10
which division of the mediastinum is posterior to pericardial sac and diaphragm
posterior
what does the inferior vena cava enter, from where and through what
right atrium from below through central tendon of diaphragm at T8 (where heart sits)
what do sensory and motor phrenic nerves innovate
diaphragm
where do the phrenic nerves originate
anterior rami of C3, 4, 5
what 4 structures do sensory phrenic nerves innovate
central tendon to diaphragm, mediastinal pleura, pericardium, peritoneum of central diaphragm
what 3 things pierce the diaphragm at T8, 10, 12
IVC, oesophagus, descending aorta structure into diaphragm
what do phrenic motor fibres supply
skeletal muscle of diaphragm
vagi in posterior mediastinum: inferior continuation
posterior oesophageal nerve, taking right vagal fibres through diaphragm to abdominal viscera
