Respiratory System Flashcards
What is inspiratory reserve volume?
The extra volume that can be breathed in at rest
What is expiratory reserve volume?
The extra volume that can be breathed out at rest.
Describe Boyle’s law
Pressure is inversely proportional to volume
Describe Charles’ law
Pressure is proportional to temperature
What is the significance of vapour pressure?
It is when water enters the gas phase. It affects the partial pressure of other substances
What are the three bony projections on the lateral wall of the nasal cavity?
Superior concha Middle concha Inferior concha
What is the function of the conchi in the nasal cavity?
Increase surface area
What type of epithelia lines the nasal cavity
Pseudostratified columnar ciliated epithelium (Except olfactory mucosa)
What forms the floor of the nasal cavity?
Soft and hard pallet
What is the main role of the nose?
Filter, humidify and warm the air
Where do serous secretions into the nasal cavity come from?
Nasoacrimal duct Sinuses
What are the four paranasal sinuses?
Frontal Ethmoid Maxillary Sphenoid
What are the three parts of the pharynx and where do they extend from/to?
Nasopharynx - nose to above lower border of soft pallet Oropharynx - border of soft pallet to the epiglottis Laryngopharynx - below tip of epiglottis
What is the function of the vocal cords?
Valve to the trachea. Close to protect it when swallowing Build pressure for the cough reflex Speech
What is the glottis?
The two vocal cords with an opening in the middle (rima glottis)
What nerve supplies the intrinsic laryngeal muscles?
Recurrent laryngeal nerve?
Why can the recurrent laryngeal nerve be affected by lung cancer, causing the voice to become hoarse?
It arises from the vagus nerve in the neck, curves around the subclavian artery/aortic arch then back up through the thorax to the vocal cords.
What type of epithelia is found in the pharynx, larynx and trachea?
Pseudostratified epithelium with cilia and goblet cells
What type of epithelia is found in bronchioles and terminal bronchioles?
Simple columnar with cilia and Clara cells
What type of epithelia lines respiratory bronchioles and alveolar ducts?
Simple cuboidal with clara cells and sparse cilia
What type of epithelia lines alveoli?
Simple squamous with type I/II pneumocytes
What type of epithelium is found in the olfactory regions of the nasal cavity?
Thick pseudostratified epithelium (no goblet cells) with microvilli, and olfactory bipolar neurons whose axons form non-motile cilia. Serous Bowman’s glands to flush the surface clear regularly.
What is the function of a Clara cell?
Secretes surfactant lipoprotein to stop the walls sticking together
What is the clinical relevance of CC16, produced by Clara cells?
Protein marker in bronchoalveolar lavage fluid. If low, indicates lung damage. If raised in serum, indicates leakage across the air-blood barrier.
What are alveolar sacs?
Composite air spaces which many alveoli open into.
Why do patients with emphysema often breathe through pursed lips?
They need to maintain back pressure to open the bronchioles as they are no longer supported by the alveolar walls which have broken down.
Give one common causative pathogen in pneumonia.
Streptococcus pneumoniae Haemophilus influenzae Staphylococcus aureus Legionella pneumophilia Mycoplasma pneumoniae
What is tidal volume?
The volume of air moving in and out with each breath during quiet respiration
What are the three parts of the sternum, from superior to inferior?
Manubrium Body Xiphoid process
What part of the sternum is used to find the second rib?
Sternal angle (angle of Louis)
What ribs are true ribs?
1-7
What ribs are floating?
11-12
Describe a ‘typical’ rib, and what numbers are they?
3-9 Head with two articular facets to articulate with the thoracic vertebra Neck with a tubercle to articulate with the transverse process of the inferior vertebra Costal groove running around to the costal cartilage.
What is the difference between rib I and typical ribs?
Rib I is shorter and more curved, with one articular facet for T1. It is flat. Has a scalene tubercle separating the anterior groove for the subclavian vein and the posterior groove for the subclavian artery
What is the difference between rib 2 and typical ribs?
Flat Poor costal groove Twice as long as rib 1
What differentiates ribs 11 and 12 from typical ribs?
A single facet on their head No tubercle Short with little curve Tapering anterior end with floating cartilage
What are the two costovertebral joints?
Head of the rib with the body of the vertebrae Costotransverse joint (tubercle of rib with transverse process)
From superficial to deep, what muscles are in the intercostal space?
External intercostal Internal intercostal Innermost intercostal
What direction do the external intercostal fibres run in?
Downwards and anteriorly
What direction do the internal intercostal muscle fibres run in?
Downwards and posteriorly
Where does the external intercostal muscle extend from and to?
From tubercles of the ribs to the costal cartilage, then continues as the external intercostal membrane
What is the function of the external intercostal muscle?
Elevation of the ribs for inspiration
Where do the internal intercostal muscles run from and to?
From parasternal region to the angle of the ribs posteriorly, where they extend to the vertebral column as the internal intercostal membrane.
What is the function of the internal intercostal muscles?
Pull down the ribs for forced expiration.
Where does the neurovascular bundle of the intercostal space run in relation to the ribs?
In the costal groove between the internal and innermost intercostal muscles.
Why would pain be referred to a specific section of skin if some of the parietal pleura was inflamed?
The intercostal nerves each supply a strip of the parietal pleura, skin and corresponding intercostal muscle.
What arteries run either side of the stenum?
Internal thoracic arteries
What arteries branch from the internal thoracic arteries to the intercostal spaces?
Anterior intercostal arteries
What artery do the anterior intercostal arteries branch from in the superior two intercostal spaces?
Superior thoracic artery
What artery gives rise to the posterior intercostal arteries?
Thoracic aorta
What is shingles?
Reactivation of the varicella zoster virus which lays dormant in the dorsal root ganglia. Reactivation causes a rash with dermatomal distribution.
Where do the azygous veins run and what vein do they contribute to?
Down the posterior thoracic cavity Contributes to the superior vena cava
What veins do the posterior and anterior intercostal veins contribute to?
External and internal thoracic veins
What do the external and internal thoracic veins drain into?
Azygous and hemiazygous veins, respectively
What are the attachments of the diaphragm?
Lower 6 ribs Arcuate ligaments (fascia over posterior abdominal muscles)
What are the crus of the diaphragm?
Fibrous attachment from the vertebra to the central tendon of the diaphragm.
What are the vertebral levels of each opening in the diaphragm and what passes through?
T8 - vena cava T10 - oesophagus T12 - aorta
What are the surface markings of the right and left domes of the diaphragm on expiration?
Right - fifth rib, mid-clavicular line Left - fifth intercostal space, mid-clavicular line
Why would there be dull percussion in the right fifth intercostal space?
The liver is in the way.
What nerve gives motor supply to the diaphragm?
Phrenic nerve (C3,4,5)
What does the phrenic nerves give sensory supply to?
Pericardium Adjacent pleura Both sides of the diaphragm
What muscles allow quiet breathing?
External intercostals Diaphragm descent
What are the accessory muscles used for forced inspiration?
Scalene Sternocleidomastoid Pectoralis major Serratus anterior
What allows quiet expiration to be passive?
Elastic recoil of the lungs and chest wall
What muscles are involved in forced expiration?
Internal intercostal Innermost intercostal Rectus abdominis External oblique Internal oblique Transverse abdominis
What does the parietal pleura line?
Pulmonary cavities, wall, mediastinum and diaphragm
What does the visceral pleura line?
Lungs, including fissures
What is the function of the pleural seal?
When the parietal pleura is pulled outwards with thorax expansion, the visceral pleura is also pulled, which expands the lungs with it.
What is the extra space in the thoracic cavity called, which isn’t filled by the lungs?
Costodiaphragmatic recess
What vertebral level does the trachea divide into the right and left bronchi?
T4/5
What structure at the base of the trachea divides the right and left bronchi?
Carina
What muscle forms a ring with the c-shaped cartilage of the trachea
Posterior trachealis muscle
Which bronchus is most likely to be the location of an aspirated foreign body and why?
Right It is shorter, wider and more in line with the trachea
What fissures are present in the right and left lungs?
Right - horizontal and oblique Left - oblique
What is the projection called on the lower part of the superior lobe of the left lung?
Lingula
Why might a tumour of the lung involve structures in the neck?
The apex of the lung extends into the root of the neck Brachial plexus (especially median branch), sympathetic trunk, subclavian vessels
What does the hilum of the lung contain?
Pulmonary vessels Main bronchus Nerves Lymphatics (drain to hilar lymph nodes)
Which nerve passes around the arch of the aorta?
Recurrent laryngeal nerve
Which nerve runs alongside the trachea?
Vagus nerve
Which nerve runs along the pericardium to the diaphragm?
Phrenic nerve
What structures are in the middle mediastinum?
Pericardium Heart Origins of the great vessels Nerves Smaller vessels
What is the vertebral levels of the superior mediastinum?
T1-4
What is in the superior mediastinum?
Thymus Right and left brachiocephalic veins Left superior intercostal vein Superior vena cava Aortic arch Trachea Oesophagus Phrenic nerves Vagus nerves Left recurrent laryngeal nerve Thoracic duct
What is in the posterior mediastinum?
Oesophagus and associated nerve plexus Thoracic aorta Azygous veins Thoracic duct and associated lymph nodes Sympathetic trunks Thoracic splanchnic nerves
What is in the anterior mediastinum?
Thymus Fat Connective tissue Lymph nodes Mediastinal branches of internal thoracic vessels Sternopericardial ligaments
What is the difference between ‘dry’ air and tracheal air?
Tracheal air is at 37 degrees and is fully saturated.
What factors affect the diffusion rate of a gas into a fluid?
Solubility Cross sectional area Distance Pressure Molecular weight Temperature in the environment/fluid
Why does carbon dioxide diffuse faster than oxygen when it is a larger molecule?
It is more soluble
Is oxygen or carbon dioxide diffusion more impaired when the diffusion distance is increased?
Oxygen
What is affected in fibrotic lung disease to change diffusion rates, and how is pO2 and pCO2 changed in plasma?
Barrier thickened pO2 decreased, pCO2 same.
How does pulmonary oedema affect gas diffusion in the lungs, and how does pO2 and pCO2 in plasma change?
Increases diffusion distance pO2 low, pCO2 normal
Why is it important that oxygen levels in the plasma reach equilibrium with the lungs with 2/3 redundancy?
In exercise, when blood is flowing faster, the rate of exchange isn’t limiting
What is the alveoli ventilation rate?
The amount of air per minute reaching the alveoli (L/min)
If the ventilation:perfusion ratio is low, what is the general issue?
Something is preventing oxygen entering the alveoli, such as a mucus plug.
What is the general issue if the ventilation:perfusion ratio is high?
Perfusion occlusion, such as a pulmonary embolus.
What is the difference between serial and distributive dead space in the lungs?
Serial - volume in the conducting airways Distributive - parts which don’t support exchange (such as dead or damaged alveoli)
What is vital capacity?
Maximum inspiration to maximum expiration
What properties of the lungs affects vital capacity?
Compliance Force of muscles Airway resistance
What is inspiratory capacity?
Largest breath in from the resting expiratory volume
What is tidal volume?
The volume of air breathed out after the deepest inhalation
What is functional residual capacity?
The volume of air present in the lungs at the end of passive expiration
What is inspiratory reserve volume?
The additional air which can be forcibly inhaled after the inspiration of normal tidal volume