lungs, pleura and ventilation Flashcards
lungs: demonstrate the surface markings of the pleura, lobes and fissures of the lungs and explain their clinical significance; describe the structures in the hilum of the lung and their anatomical relationships; summarise the anatomy of the bronchial tree and bronchopulmonary segments, explain their functional and clinical significance and describe the blood supply, innervation, venous and lymphatic drainage of the lungs
4 sections of the bronchial tree (superior to inferior)
centrally-located trachea, primary (main) bronchi (left and right), lobar (secondary) bronchi, segmental (tertiary) bronchi
where does the trachea extend
from vertebral level C6 to T4/5 (2nd costal cartilage slopes down so is T4/5)
what is the trachea held open by
C-shaped cartilage rings
what does the lowest tracheal ring have
hook (carina); lymph nodes underneath so may alter appearance if sinister
where is the primary bronchi formed
T4/5
difference between right and left primary bronchi
right is wider and more vertical
where are the lobar bronchi formed
within lungs
what do the lobar bronchi do
supply lobes of lungs
what do the segmental bronchi do
supply bronchopulmonary segments (self-contained independent units of lung tissue - can be removed without affecting neighbouring regions)
how many lobes on the left lung
2
how many lobes on the right lung
3
diagram of the bronchial tree
slide 4/5
how many bronchopulmonary segments in each lung
10
where are the lungs situated
thorax
what separates the lungs
heart and other contents of mediastinum
what does each lung lie in
pleural cavity (fluid between two layers, creating surface tension), apart from attachment to heart (pulmonary vessels) and trachea at lung root (hilum)
what passes from mediastinum through lung roots into lungs
vessels, nerves and bronchi
what shape are the lungs
conical
characteristics of lung apex in relation to thoracic inlet and first costal cartilage
oblique to thoracic inlet, rises 3-4cm above level of first costal cartilage
what shape is the lung base
concave
what does the lung base rest on
convex surface of diaphragm
3 borders of the lung base
anterior, posterior, inferior
3 surfaces of the lung base
costal (outer), medial (mediastinal), inferior (diaphragmatic)
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
what is the posterior part of the mediastinal surface of lung in contact with, and why is it thick
thoracic vertebra, thick and ribs emerge posteriorly before turning anteriorly so some ribcage behind vertebral column to allow upright standing
what is the shape of the anterior part of the mediastinal surface of lung
deeply concave
what does the anterior part of the mediastinal surface of lung accomodate
heart (cardiac impression is larger on left than right because of position of heart)
what is behind the above and behind cardiac impression of the mediastinal surface of lung
hilum (pleural reflection) where vessels, bronchi and nerves enter and leave mediastinum
what are the 2 lobes of the left lung
superior, inferior
what separates the 2 lobes of the left lung
oblique fissure; lingula is a flap of tissue which projects forward just in front of heart on left lung; groove for aorta
where does the superior lobe lie in relation to the fissure and what does it include
lies above fissure and includes apex and most of anterior part of lung
what are the 3 lobes of the right lung
superior, middle, inferior
what separates inferior lobe from other 2 lobes
oblique fissure; groove for oesophagus and superior vena cava; different arrangement of vessels to left
what separates superior lobe from middle lobe
horizontal fissure
which lung is larger
right
what does the root (hilum) of the lung do
connects mediastinal surface of heart to trachea
what is the hilum formed of
primary bronchus, pulmonary artery, 2 pulmonary veins, bronchial arteries and veins, pulmonary plexus of nerves, lymph vessels and nodes
what envelopes all of the structures of the hilum
continuous pleura
what is the pleura
thin layer of flattened cells supported by connective tissue that lines each pleural cavity and covers exterior of lungs
what are the 2 layers of the pleura
visceral and parietal
what does the visceral pleura do
covers surface lungs and lines fissures between lobes
what does the parietal pleura do
lines inner surface of chest walls
features of pleural cavity in living humans
collapsed (largely touching), but moist surfaces allow lungs to glide as they expand and collapse
what is the pleural origin
pleural cavities exist inside chest wall lined by parietal pleura → lung buds grow into them → visceral pleura forms as lung buds grow into visceral pleura covering (diagram from slide 19)
features of costodiaphragmatic recess of pleura
free of lung except in maximal inspiration (visceral pleura: 4th costal cartilage and 4th rib laterally until oblique fissure where it follows 6th rib; parietal pleura: all ribs)
what controls and what produces breathing
nervous system, skeletal muscle
what are the gas exchange areas called
alveolar sacs
how can the capacity of the thoracic cavity be increased
movements of diaphragm, movements of ribs
how does skeletal muscle result in mechanism of breathing
pleural cavity expanded by muscles in walls → elastic lungs expand with pleural cavity, sucking air down trachea and bronchi into lungs
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
during breathing, why are the ribs elevated
increases antero-posterior dimension of thoracic cavity (pump-handle)
during breathing, why are the ribs everted
increases transverse diameter of thoracic cavity (bucket-handle)
why do internal and external intercostal muscles stiffen rib cage
increase efficiency of diaphragm
what does quiet expiration depend on and hence what type of activity is it
depends on elastic recoil in elastic tissue throughout lungs and rib cage, so is passive
what is deep expiration assisted by
muscles of abdominal walls that squeeze abdominal organs against diaphragm and pull lower ribs downward
great vessels
pulmonary trunk to artery; aorta (also to coronory arteries); superior vena cava (braciocephalic arteries) near sternoclavicular joint
surface markings of pleura, lobes and fissures
Netter’s anatomy flashcards
