Respiratory S2 (Done) Flashcards
Label the boxes from top down
Jugular notch
Clavicle
Sternal angle
Costal margin
Describe the anterior associations of the ribs and their costal cartilages
Ribs 1-7:
Connected by costal cartilages directly to sternum
Ribs 8-10:
Connected by costal cartilage to the costal cartilage above
Ribs 11-12:
Free floating, no connection to sternum/cartilage
Label this diagram from top down
The typical rib:
Head
Neck
Shaft
2 articular facets separated by crest
Tubercle (Top = articular, Bottom = non-articular)
Costal groove
What ribs are considered typical?
Ribs 3 to 9
Label each of these ribs with their number and features that make them ‘atypical’
Top to bottom:
Rib 1:
shortest, broadest, most curved, only has 1 facet on head
Rib 2:
Poorly marked costal groove
Ribs 11 + 12:
Floating
Single facet on head
No tubercle
Tapering anterior end
Label the boxes
First set of boxes
Participants in joint of head of rib:
Body of vertebra superior to rib
Intervertebral disk
Body of vertebrae same number as rib
Second set of boxes
Costo-transverse joint:
Transverse process of vertebra of same number as rib
Tubercle of rib
Axis of rib rotation
Movements (the arrows):
Elevation
Depression
Label the black and red boxes
Black, top left clockwise:
Axis of movement
Axis of movement
Increase in sagittal diameter
Increase in transverse diameter
Neck of rib
Red, left to right:
Lower rib
Upper rib
What are the three layers of intercostal muscle
Give a brief description of each
External intercostals:
Fibre direction is posterior to anterior from the inferior border of the superior rib to the superior border of the inferior rib
Outermost
Internal intercostals:
Fibre direction is anterior to posterior from the inferior border of the superior rib to the superior border of the inferior rib
Middle layer
Innermost intercostals:
Run from the inferior border of the superior rib to the superior border of the inferior rib
Innermost layer
Label the boxes top to bottom
External intercostal muscles
Internal intercostal muscles
Innermost intercostal muscles
Describe the actions of the external intercostal muscles
Elevation of the upper ribs in a ‘pump handle’ movement to increase A-P diameter of thorax
Elevation of lower ribs in a ‘bucket handle’ movement increasing the lateral diameter of the thorax
Describe the actions of the internal and innermost intercostal muscles
Depress the ribs during forced expiration
Reduces A-P and lateral diameter
What muscles are responsible for passive expiration?
No muscles, passive process driven by elastic recoil of lungs and chest wall
What structures are labelled here?
Two neurovascular bundles
Main bundle includes intercostal vein, artery and nerve and runs in costal groove of superior rib
Collateral bundle runs along the superior border of the inferior rib
Describe the 12 intercostal nerves
Course:
Appear from the anterior rami of thoracic spinal nerves (T1 - T12)
Run between internal and innermost intercostal muscles
Supply:
Intercostal muscles in corresponding space
Parietal pleura
Overlying skin
Label the boxes from top left clockwise
Paravertebral chain
Intercostal nerve
Posterior intercostal artery
Anterior intercostal artery
What is supplied by the intercostal arteries?
Intercostal muscles
Parietal pleura
Overlying skin
Label boxes in two rows, Left row then right row, top to bottom
Left:
Superior vena cavae
Azygous vein
Hemiazygous
IVC
Right:
Anterior intercostal vein
Internal thoracic vein
Posterior intercostal veins
From where do the posterior and anterior intercostal arteries arise?
Anterior:
Internal thoracic artery (branch of the subclavian)
Posterior:
Thoracic aorta
Superior intercostal artery (From the costo-cervical traunk, a branch of the subclavian)
Describe the venous drainage of the chest wall
Primarily into the Azygous system —> SVC
Some drainage into internal thoracic vein
Describe the structure of the diaphragm
Central tendon + Peripheral uscle
Peripheral muscle areas:
Sternal - Arising from xiphisternum
Costal - Arising from inner aspects of the 7-12 costal cartilages
Vertebral - Arising from arcuate ligaments (thickenings of fascia over the posterior abdominal wall muscles) + crura
Label black boxes from top left clockwise
IVC opening
Central tendon
Oesophaseal opening
Aortic hiatus w/median ligament overlying
Left crus
Right crus
Lateral arcuate ligament
Medial arcuate ligament
Give the vertebral level of the openings in the diaphragm and attachment sites of the right and left crus
**Oesophagus: **
T10
Vena cava:
T8
Aortic Hiatus:
T12
Right crus:
L4
Left crus:
L3
What is the function of the diaphragm in relation to breathing?
Main muscle of inspiration
Contraction causes descent of diaphragm, expanding the thoracic cavity
Describe the nerve supply of the diaphragm
Include any additional innervation of that nerve
Phrenic nerve
Roots:
C3 - 5 (3-4-5 keep you alive)
Motor innervation:
Diaphragm
Sensory innervation:
Pericardium
Mediastinal and diaphragmatic portions of parietal pleura
Both surfaces of diaphragm
What muscles/actions are involved in inspiration?
What are the results of these muscle actions?
External intercostals:
Elevation of ribs
Contraction of diaphragm:
Descent
Sternocleidomastoids:
Elevates sternum
Scalenes:
Elevate and fix upper ribs
Results:
Increased transverse and A-P diameter
Increase in vertical dimension
Describe the process of expiration in regards to actions/muscles involed
Quiet expiration:
No muscles, just elastic recoil
Forced expiration:
Internal and innermost intercostals
Rectus abdominus
External and internal obliques
Transversus abdominus
Results of either passive or forced:
Decrease in AP and transverse diameter
Decrease in the vertical dimension
What is the involvement of the pleura in respiration?
Briefly describe how this works
As muscle action expands the thorax and the parietal pleura the pleural seal ensures that the visceral pleura and hence the lung also expand
The pleural seal is formed from surface tension between fluid molecules of the serous secretions in the pleural cavity
What is the clinical relevance of the pleural seal?
Puncture of the parietal pleur breaks the pleural seal, allowing the visceral and parietal pleura to separate, this is a pneumothorax (lung collapse)
Decribe the nerve supply of the pleura
Parietal:
Somatic innervation (including pain) and autonomic
Visceral:
Only autonomic
Describe the blood supply of the pleura
Parietal:
Intercostal arteries and internal thoracic artery
Corresponding veins drain
Visceral:
Bronchial arteries
Bronchial veins
Describe the anatomical location and important features of the trachea
Extends from the lower border of the cricoid cartilage to the division od bronchi at the carina (Spinal level T4/5)
Fibro-cartilagenous tube
18-22 U shaped cartilage rings
Trachealis muscle posteriorly
What is the clinical relevance of the angle of tracheal bifurcation?
If angle is wider than normal this indicates swollen tracheo-bronchial lymph nodes
What is a broncho-pulmonary segment and what is the clinical relevance?
Broncho-pulmonary segment:
Area of lung supplied by its own segmental bronchus and segmental branches of pulmonary arteries and veins
Pyrimidal in shape, apex towards hilum, base towards lung surface
Clinical:
Segment can be isolated and removed with little damage to others (E.g. removal of small primary or metastatic tumours)
What is the apex of the lung and why is it clinically relevant?
Apex:
Superior portion of the lung extending superiorly through the superior thoracic inlet and to the base of the neck
Clinical:
Apical lung tumours can compress structures in root of neck (E.g. brachial plexus, subclavian vessels, sympathetic trunk)
Subclavian vein cannulation can lead to pleural puncture (pneumothorax)
What structures pass throught the lung Hilum?
Pulmonary and bronchial arteries and veins
Bronchi
From where do the bronchial arteries arise? where do they supply?
What is the role of the bronchial arteries in venous drainage of the lungs?
Arteries:
Arise from aorta on left and 3rd intercostal on right
Supply bronchial tree from the carina to the respiratory bronchioles, visceral pleura and connective tissue
Veins:
Most drainage is via pulmonary veins rather than bronchial
Superifical bronchial veins drain the visceral pleura and bronchi in the hilar region into the azygous vein on the right and hemiazygous vein on the left
Deep group drain the deeper bronchi into the pulmonary vein
Label the black boxes and identify each lung
Lung pictured left, boxes from top to bottom, left to right:
Right lung
Pulmonary arteries
Bronchus
Pulmonary veins
Pulmonary ligament
Lung pictured right, boxes from top to bottom:
Left lung
Pulmonary artery
Bronchus
Pulmonary veins
PIctured are the right and left mediastinal spaces with lungs removed, identify the structures labelled
Left picture, top to bottom:
Sympathetic chain
Vagus nerve
Phrenic nerve
Right picture, top to bottom:
Reccurent larangeal nerve (branch of vagus)
Vagus nerve
Phrenic nerve
Aorta
Label the boxes and identify the borders of each mediastinal space
Boxes, top to bottom, left to right:
Anterior
Body of sternum
Fibrous pericardium
Superior
Thoracic inlet
Plane passing throught sternal angle and lower border of T4
Middle
Between anterior and posterior
Posterior
Fibrous percardium
Vertebral bodies
Describe the nerve supply of the lungs
Lung recieves innervation from differnt nerves all via the pulmonary plexuses at each lung hilum
Vagus Efferent:
Parasympathetic nerves provide motor innervation to bronchial smooth muscle (constriction)
Pulmonary vasoldilation
Secretomotor innervation to mucous glands
Vagus afferent:
cough reflex
Subserving pain
Sympathetic trunk:
Bronchodilation
Vasoconstriction
Describe the lymphatic drainage of the lungs
Superficial sub-pleural lymphatic plexus:
Lies deep to visceral pleura
Drains lung parenchyma and visceral pleura
Drain into hilar lymph nodes at each lung hilum
Deep broncho-pulmonary lymphatic plexus:
Lies in the submucosa of bronchi and peribronchial tissue
Drain into the hilar nodes
What si the normal composition of alveolar air? Give partial pressures
pO2 = 13.3kPa
pCO2 = 5.3kPa
Give the normal gaseous content of mixed venous blood returning to the lungs
pO2 = 6kPa
pCO2 = 6.5kPa
Can vary with metabolism
Identify the direction of gas gradients across the alveolar membrane and hence give direction of movement of each gas
pO2:
13.3kPa > 6.0kPa
Therefore O2 moves into alveolar capillaries
pCO2:
5.3kPa < 6.5kPa
Therefore CO2 diffuses into alveoli
Aside from gradient what factors influence diffusion of gases across the alveolar membrane?
Surface area (Ideally large)
Diffusion resistance (Ideally low)
What factors influence diffusion resistance?
Nature of gas
Nature of barrier
Describe the diffusion barrier in the lungs
Diffusion occurs across alveolar wall and into RBCs therefore barrier made up of:
Epithelium of alveolus
Tissue fluid
Endothelial cells of capillary
Plasma
Red cell membrane
Total = 0.6um
Which diffuses faster, Co2 or O2? Why?
CO2 (x21):
Gases diffuse at rate proportional to solubility
Therefore CO2 faster
Apart from solubility what other feature of gases goes towards determining diffusion rate?
Molecular weight:
Gases diffuse at rate inversely proportional to molecular weight
Houw long does it take for partial pressures of alveolar gases and blood gases to equilibrate in the lung?
How long do blood cells spend in the alveolar capillaries and why is this relevant?
0.5s
1s
Relevance:
Plenty of leeway, diffusion not limiting on lung function
What are the partial pressures of gases in blood leaving the alveolar capillaries?
**pO2 = **13.3kPa
**pCO2 = **5.3kPa
Describe the process of ventilation and what it achieves
Expansion of the lungs increasing the volume of respiratory bronchioles and alveolar ducts, drawing air into them
Air is not drawn directly into alveoli, fresh air is an incorrect mix
Raises pO2 and lowers pCO2 in alveoli
Label the boxes and define the terms
Top to bottom
Inspiratory reserve:
Extra volume that can be breathed in over that inspired at rest
Tidal volume:
Volume in and out with each breath at rest
Expiratory reserve volume:
Extra volume that can be breathed out over that expired at rest
Label the box and define
Give how this volume is measured
Residual volume:
Volume left in lungs at maximal expiration
Measured with a helium dilution test
Label the box, define it and give it’s typical value
Vital capacity:
Measured from maximal inspiration to maximal expiration
About 5L in typical adult
Cn be altered by disease
Label the box, define it and give it’s typical value
Inspiratory capacity:
Measured from resting expiratory level to maximal inspiration
Typically 3L
Label the box, define it and give typical value
Functional residual capacity:
Volume of air in lungs at resting expiratory level
(Expiratory reserve + Residual volume)
Typically 2L
Define ventilation rate
Volume of air moved into and out of a space (lungs) per minute
Product of volume per breath and resp rate
Give the exquation of pulmonary ventilation rate and the typical values
Tidal volume x resp rate
Typically 8L.min-1
Can exceed 80L.min-1 in exercise
How does alveolar ventilation rate differ from pulmonary ventilation rate?
Discounts volume of air only moved into dead spaces in the lung where no gas exchange occurs (bronchi etc)
Define ‘serial dead space’
How is it measured?
Give a typical value
Volume of the airways
Used to be known as ‘anatomical dead space’
Measured via nitrogen washout test
Typically 0.15L
Define ‘distributive dead space’ and ‘physiological dead space’
Give typical values
Distributive:
Parts of the lungs that do not support gas exchange but are not airways, including:
- Dead or damaged alveoli
- Alveoli with poor P/V ration
Physiological:
Distributive + Serial dead space to give total ‘dead space’
Typically 0.17L
