Anatomy 2 - Thorax: Internal Organisation And Lower Respiratory System Flashcards
1
Q
Thorac internal organisation
A
- 3 compartments: 2 pulmonary cavities (contain lungs) and one mediastinum (contains heart, vessels, nerves, trachea, bronchi, oesophagus, lymphatics. Divided by pericardium
2
Q
Mediastinum - Divisions
A
- Superior mediastinum - above sternal angle
- Infersios mediastinum - below sternal angle. Further divided into anterior mediastinum (in front of heart), middle mediastinum (At heart) and posterior mediastinum (behind heart)
3
Q
Contents of superior mediastinum
A
- thymus
- braciocephalic vein
- SVC
- Aortic arch
- brachiocephalic trunk
- common carotid artery
- subclavian artery
- trachea
- oesophagus
- thoracic duct
- vagus and phrenic nerve
4
Q
Anterior mediastinum content
A
- thymus (children)
- fat (adults)
- lymph nodes
- ligaments between pericardium and sternum
5
Q
Middle mediastinum contents
A
- Heart
- root of great vessels
- pericardium
- phrenic nerve
6
Q
Posterior mediastinum content
A
- bronchi
- thoracic aorta and branches
- oesophagus
- bagal and sympathetic trunks
- thoracic duct
- azygos and hemiazygos veins
7
Q
Upper respiratory system
A
- nasal cavity
- pharynx
- larynx
8
Q
Lower respiratory system
A
- trachea
- bronchi (bronchioles, alveoli)
- lungs
- pleura
9
Q
Trachea
A
- long (10-12cm) fibromuscular tube supported by cartilage, provides passage of air from pharynx to lungs
- Extends along vertebral bodies from lower end of larynx through mediastinum to bifurcate into 2 principal bronchi at the carina (at the level of the sternal angle (TV4/5)
- fibroelastic tissue allows for stretch and recoil during aspiration
- 16-20 C-shaped hyaline cartilage rings that are completed by smooth muscle posteriorly which expands to let food pass throu oesophagus on swallowing
10
Q
Trachea - visceral relationships
A
- contained within the nech, the thoracic inlet ant the superior mediastinum
- within superior mediastibum, trachea is related to Manubrium, aortic arch, brachiocephalic trunk, left common arotid, left brachiocephalic, thymus, oesophagus and left recurrent laryngeal nerve
11
Q
Bronchi
A
- the 2 cartilage ring-reinforced proncipal bronchi lie behind the heart in the posterior mediastinum and pass into each lung root before branching
- right principal bronchus is shorter, wider and more vertical than the left
12
Q
BRonchial tree
A
- 1º principal bronchi divide into lobar (2º) bronchi: one for each lung lobe
- Lobar bronchi divide into segmental (3º) bronchi - corresponds to various bronchopulmonary segments
- segmental bronchi divide until they become cartilage-free terminal bronchioles
- terminal bronchioles divide into respiratory bronchioles which develop into alveoli and alveolar sacs
13
Q
How many alveolar sacs are they by lung?
A
- 300 million
14
Q
Bronchial tree: blood supply
A
- bronchi and pulmonary arteries are paired and branch in unison
- each intrasegmental pulmonary artery carry poorly oxygenated blood from heart and ends in a capillary plexus in the walls of the alveolar sacs and alveoli: where CO2 and O2 are exchanged
- intersegmental pulmonary veins arise from pulmonary capillaries and carry well oxygenated blood back to the heart
15
Q
Bronchopulmonary segments
A
- make up the substane of the lung
- the area of lung supplied by a segmental bronchus and its accompanying pulmonary branch
- 10 in each lung
- smallest functionally independent region of a lung that can be isolated and removed without affecting adjacent regions
- surgically resectable, but malignancies may disrupt septa of segments making resection more complicated or more extensive
16
Q
Lungs
A
- covered by pleura
- occupy pulmonary cavities
- Apex extends into root of neck above 1st rib
- Base rests on diaphragm
17
Q
Right lung
A
- larger
- shorter because liver pushes up
- wider because heart on left
- 3 lobes: Upper, middle, lower
- 2 fissures: oblique, horizontal
- related to: heart, IVC, SVC, subclavian vein, subclavian artery, azygos vein, oesophagus, 1st rib
18
Q
Left lung
A
- smaller, longer, narrower
- divides into 2 lobes: upper + Lower
- 1 fissure: oblique
- has a cardiac notch and lingula
- related to: the heart, the aortic arch, the thoracic aorta, the brachiocephalic vein, the subclavian artery, the oesophagus, the 1st rib
19
Q
Pulmonary hilum
A
- where structures enter and leave the lungs from
- surrounded by a pleural sleeve
- drapes inferiorly to create the pulmonary ligament
- veins are anterior and inferior
- arteries are superior
- bronchi are posterior
- pulmonary ligament inferior
- lymph nodes are scattered
20
Q
What is the different organisation in left and right hilum dure to
A
- due to twist in left pulmonary artery and left bronchus that results in left pulmonary artery being superior to bronchus rather than anterior
21
Q
Pleura
A
- each lung has its own pleural sac
- visceral plerau adheres to lungs and extends into fissure
- Parietal pleura contacts the costal wall, diaphragm, mediastinum and into root of neck on apex (cupula)
- serous pleural fluid keeps pleural layers clinging together
- visceral pleara and parietal pleura are contibuous at hiulm and drape inferiorly to form pulmonary ligament
22
Q
Recesses
A
- the lungs do not compeltely fill the parietal sacs - creates recesses
- when 2 layers of parietal pleura contact each other
23
Q
Costodiaphragmatic recess
A
- most clinically important
- point of fluid collection
- between inferior margin of lungs and inferior border of pleural cacvities
- enlarge with expiration
- deeper posteriorly, behind diaphragm
24
Q
Costomediastinal recess
A
- largest on the left side over the heart at cardiac notch
25
Q
Pleural fluid
A
- between the visceral and parietal layers of pleura
- keeps themn clinging together under fluid surface tension
- maintenance of this surface tension prevents lung from collapsing
- if air or blood enters the pleural fluid, the surface tension is broken and then the lung can collapse
26
Q
Resp system arterial supply
A
- respiratory parts (bronchioles and alveoli: pulmonary arteries from pulmonary trunk
- condicting parts (trachea to bronchioles): bronchial arteries from thoracic aorta
27
Q
Respiratory system: venous drainage
A
- respiratory parts: pulmonary veins
- conducting parts: bronchial veins to azygos system
28
Q
Trachea lymphatics
A
- tracheobronchial nodes to bronchomediastinal trunk to junction of internal jugular and subclavian veins
29
Q
Visceral pleura and superficial lung lymphatic
A
- subpleural lymphatic plexus to bronchomediastinal trunk to junction of internal jugular and subclavian veins
30
Q
Deep lung lymphatics
A
- bronchopulmonary nodes to bronchomediastinal trink to junction of internal jugular and subclavian veins
31
Q
Phrenic nerve
A
- motor innervation to diaphragm
- noxious innervation of parietal pleura
32
Q
Sympathetic trunk
A
- Sympathetic asutonomic innervation
- causes bronchodilation, pulmonary blood vessel constriction, reduces secretion, inreases resp rate
33
Q
Vagus nerve
A
- from brain
- parasympathetic autonomic innervation
- causes bronchoconstriction, dilation of blood vessels, increased secretion, decreased resp rate, non-noxious innervation of pleura
34
Q
Thoracic mechanism of respiration
A
- when intercostal muscles pull a rib up, it moves the sternum forward, expanding the anterior posterior dimensions: pump handle
- when intercostal muscles pull a rib up, it expands the lateral dimensions of the thoracic wall, flaring out the sides (bucket handles)
- lungs recoil passively when thoracic muscles relac
35
Q
Thoracic muscles of respiration
A
- diaphragm is primary muscle. Intercostal muscles only assist
36
Q
Quiet inspiration
A
- contraction (descent) of the diaphragm and intercostal muscles of the thorax
- lung expand
37
Q
Quiet expiration
A
- relaxation of diaphragm and itnercostal muscles of the thorax
- passive lung recoil
38
Q
Forced inspiration
A
- add action of scalenes
- pec major
- minor and sternocleidomastoid muscles to elevate sternum more
39
Q
Forced expiration
A
- add action of quadratus lumborum to fix 12th rib, anterolateral abdominal wall muscle to depress lower ribs and increae intra-abdominal pressure, internal intercostals to depress sternum deeper
