RS Flashcards
What is vital capacity?
The greatest volume of air that can be exhaled from the lungs after taking the deepest possible breath
What is the vital capacity used to measure?
Lung volume
What is the parasympathetic neurotransmitter in the lung?
Acetylcholine
What is the sympathetic neurotransmitter in the lung?
Noradrenaline
Where are the frontal sinuses?
Within the frontal bone, in the midline septum, but this may not be in the midline. Over the orbit and across the superciliary arch.
What is the nerve supply of the frontal sinuses?
The ophthalmic branch of the trigeminal nerve
Where are the paranasal sinuses?
Pneumatised areas of the frontal, maxillary, ethmoid and sphenoid bones. They are arranged in pairs.
What are the paranasal sinuses?
The are envaginations of the mucous membrane from the nasal cavity. They are lined with cilia
What are the functions of the nose?
It regulates temperature and humidity of inspired air; it has a filter function (mammals are obligate nasal breathers); it has a defence function ( lined with cilia)
Where does the anterior nares lead to?
The anterior nares (nostrils) open into the enlarged vestibule (skin-lined and has stiff hairs).
What do the turbinates do?
They double the surface area of the nose. They create the superior, middle and inferior meatus’
Where are the maxillary sinuses?
They are located within the body of the maxilla. They are a pyramidal shape.
What is the base of the maxillary sinuses?
The lateral wall of the nose
What is the apex of the maxillary sinuses?
The zygomatic process of the maxilla
What is the roof of the maxillary sinuses?
The floor of the orbit
What is the floor of the maxillary sinuses?
The alveolar process
Where do the maxillary sinuses open into?
The Middle meatus via the hiatus semilunaris. They train all the liquid into the middle meatus
Where are the ethmoid sinuses?
They are between the yes. They are a labyrinth of air cells
What is the nerve supply of the ethmoid sinuses?
The ophthalmic and maxillary branches of the trigeminal nerve
Where are the sphenoid sinuses?
Medial to the cavernous sinus and inferior to the optic canal, dura and pituitary gland
Where do the sphenoid sinuses empty into?
The sphenoethmoidal recess, lateral to the attachment of the nasal septum
What is the nerve supply of the sphenoid sinuses?
The opthalmic branch of the trigeminal nerve
What is the pharynx?
It is a fibromuscular tube that goes from the skull base to the oesophagus. It consists of the nasopharynx, oropharynx and laryngopharynx
What is the epithelium of the pharynx?
It is lined with squamous and ciliated epithelium with interspersed mucous glands
Where is the nasopharynx?
It is bound by the base of the skull, the sphenoid rostrum, C spine, posterior nose and opens into the oropharynx.
Where are the pharyngeal tonsils?
They are located on the posterior wall of the nasopharynx
Where do the eustacian tube orifices open into?
The lateral wall of the nasopharynx to supply air to the middle ear
What is the oropharynx?
It is a tube to take air from the aural cavity into the lung
What is the oropharynx bound by?
The soft palate anteriorly. The hyoid bone superiorly. It goes from the nasopharynx to the laryngopharynx
Where are the palatine tonsils?
The palatine tonsils are on the lateral walls of the oropharynx. The palatoglossal folds are the anterior arches and the palatopharyngeal folds are the posterior arches
What are the types of laryngeal cartilages?
Single and double. There are 9 in total.
What are the single laryngeal cartilages?
The epiglottis, the thyroid cartilage and the cricoid cartilage
What are the double laryngeal cartilages?
The cuneiform cartilages, the corniculate cartilages and the arytenoid cartilages
What is the function of the larynx?
It has a valvular function so prevents liquids and food entering the lungs.
What is the structure of the larynx?
It has a rigid structure made of multiple muscles and 9 cartilages.
What nerves is the larynx innervated by?
It is supplied by vagus branches: the superior and recurrent laryngeal nerves.
What is the path of the superior laryngeal nerve?
It comes from the inferior ganglion down the lateral pharyngeal wall and divides into the internal (sensation) and external (cricothyroid muscle) superior laryngeal nerves.
What does the recurrent laryngeal nerve supply?
It supplies all muscle but the cricothyroid. It ascends between the trachea and oesophagus
What are the components of the lower respiratory tract?
It is below the stern all angle. It consists of the pleura and the main airways: the trachea, the main bronchi, the lobar bronchi, the segmental bronchi, the terminal bronchioles, the respiratory bronchioles, the alveolar ducts and the alveoli
What is the function of the lower respiratory tract?
It’s main function is gas exchange. It has 20m2 gas exchange area per lung. The minute ventilation and cardiac output are approx. 5L/min. There are regional differences in ventilation and perfusion
Where is the trachea?
It is from the larynx to the carina, which is at T5 level.
What shape is the trachea?
It is oval-shaped with semi circular cartilages
What is the lining of the trachea?
Pseudo-stratified, ciliated columnar epithelium with interspersed goblet cells
What are the two main bronchi?
The trachea splits into the right main bronchi and the left main bronchi at the carina.
What is the difference between the left main bronchus and the right main bronchus?
The left main bronchus is a lot less verticle and is longer. It is 5cm long and it related to the aortic arch. The right main bronchus is 1-2.5cm long and is related to the right pulmonary artery
What is antibody opsonisation?
It is the process by which a pathogen is marked for ingestion and eliminated by a phagocyte
What is a cough?
A cough is an explosive expiration that provides a normal protective mechanism for clearing the tracheobronchial tree of secretions and foreign material
How main lobar bronchi are there?
3 on the right (upper, middle and lower) and 2 on the left (upper and lower).
What is the acinus?
It is the area distal to the terminal bronchiole. The short tube ducts with multiple alveoli
What are the pores of Kohn?
The interconnections between the alveoli
What are the components of alveoli?
There is a basement membrane, interstitial tissue and capillary endothelial cells. There are also alveolar macrophages
What are the two types of alveoli?
Type 1 pneumocytes, which cover 90-95% of the surface and aid gas exchange. Type 2 pneumocytes, which cover 5-10% of the surface and decrease surface tension and secrete surfactant
What does lung innervation control?
Many aspects of function; smooth muscle tone, mucous gland secretion, blood flow and vascular permeability
What does sympathetic innervation of the lung cause?
Bronchodilation
What does parasympathetic innervation of the lung cause?
Bronchoconstriction
What are the two circulation systems in the lung?
There are bronchial and pulmonary circulation systems
What are the muscles of inspiration?
Largely due to the diaphragm (C3,4,5) and external intercostals (nerve roots at each level)
What are the muscles of expiration?
It is passive during quiet breathing
What is the motor innervation of respiration?
The diaphragm is innervated by C3,4,5 and the internal intercostals are innervated by thoracolumbar nerve roots at each level
What is the sensory innervation of respiration?
There are afferents via the vagus nerve. There are sensory receptors. There are C fibres (small nerve fibres)
Where is resistance highest in the respiratory airways?
In the main airways, terminal bronchi
What is dead space?
Areas of the lung where air is supplied but no gas exchange takes place
What are the two layers of lung pleura?
Visceral (applied to the lung surface) and parietal (applied to the internal chest)
What is the visceral pleura innervated by?
It is only innervated by autonomic innervation
What sensation does the parietal pleura have?
It only senses pain
How thick are the lung pleura?
They are only a single cell later but they are continuous with each other at the lung root. There is a small amount of fluid between the layers
What properties of the lug allow expiration?
Both the chest wall and the lungs have elastic properties and a resting volume. Changing this volume requires force. Release of this force leads to a return to the resting volume
When are capillaries perfused with blood?
They are the most dependant parts of the lung and are preferentially perfused with blood at rest
What affects the perfusion of capillaries?
It depends on pulmonary artery and venous pressure. Certain pulmonary arteries have smooth muscle within their walls which create resistance
What is the PaCO2?
The arterial CO2
What is the PACO2?
The alveolar CO2
What is the PaO2?
The arterial O2
What is the PAO2?
The alveolar O2
What is the PIO2?
The pressure of inspired oxygen
What is the V’A?
The alveolar ventilation
What is the V’CO2?
The CO2 production
What are the oxygenation sites in the lung?
The alveolar epithelium, the tissue interstitium, the capillary endothelium, the plasma layer, the red cell membrane, the red cell cytoplasm and the Hb binding forces
What are the causes of hypoxaemia?
Alveolar hypoventilation, reduced PIO2, diffusion abnormality, ventilation/perfusion mismatch
How is CO2 transported?
It binds to Hb, or it is dissolved in the plasma or it reacts with H2O to form HCO3-
How is PaCO2 calculated?
kV’CO2/V’A = PaCO2
What is the Henderson-Hasselbach equation?
pH = 6.1* + log10([HCO3-][0.03*PCO2])
What is * in the Henderson-Hasselbach equation?
A dissociation constant
What is 0.03*PCO2 in the Henderson-Hasselbach equation?
The estimate of H2CO3
How is change in pressure worked out?
Flow x resistance
What is laminar flow?
It is low velocity / density. The change is pressure is proportional to the flow
What are the lung defence mechanisms?
There are innate immune mechanisms; non-immune mechanisms; adaptive mechanisms
What are epithelial chemical barriers?
Antiproteinases; anti-fungal peptides (alpha defensins); anti-microbial peptides (beta defensins); surfactant -A and -D proteins opsonise pathogens
How does turbulent flow affect pressure?
The change in pressure is proportional to the flow squared
What is poiseuilles law?
Airways resistance is proportional to the fourth power of the radius
What are some acid-base disorders?
Respiratory acidosis; respiratory alkalosis; metabolic acidosis; metabolic alkalosis
What is respiratory acidosis?
Increased PaCO2, decreased pH, mild increase HCO3- (barely breathing)
What is respiratory alkalosis?
Decreased PaCO2, increased pH, mild decrease HCO3- (heavy breathing)
What is metabolic acidosis?
Reduced HCO3-, decreased pH
What is metabolic alkalosis?
Increased HCO3-, increased pH
What is FEV1?
Forced expiratory volume in one second
What is FVC?
Forced vital capacity
What is PEF?
Peak expiratory flow
What is boyles law?
At a constant temperature for a fixed mass, the absolute pressure and the volume of a gas are inversely proportional
What is the peak expiratory flow?
It is a single measure of the volume expired in the first 0.1 second of forced expiration in L/min
What are the bad things about the peak expiratory flow?
It is less reproducible than FEV1. It is very effort dependant.
What is gas dilation?
It is a measurement of all air in the lungs that communicates with the airways. It doesn’t measure air in non-communicating bullae.
How does gas dilation work?
It uses open-circuit nitrogen washout. Give the patient a known concentration of gas, take gas from them and measure the difference. The patient breathes 100% oxygen and all the nitrogen in the lung is washed out
What is FEF25?
The flow at the point when 25% of the total volume to be exhaled has been exhaled
How is forced expiration measured?
Breathe into total lung capacity, exhale as fast as possible to residual volume, the volume produced is the vital capacity.
How does expiration vary during forced expiration?
There is rapid exhalation in the first second, it takes 4 seconds to empty your lungs because of the elastic recoil
How does FEV change with age
It takes longer as your get older
How does flow differ with volume?
The flow is greatest at the start of exhalation. The volume declines linearly with flow, as the volume decreases, the flow does
What does exhaled nitric oxide measure?
An indirect reflection of airways inflammation. Exhaling from total lung capacity into gas analyser under positive expiratory pressure. 5-20ppb is normal. There are nasal NO issues
How does airways resistance vary?
An increase in turbulence increases resistance. At total lung capacity, resistance is low. During expiration airway diameter decreases and resistance increases.
What is conductance?
It is the opposite of resistance
What is lung compliance?
It is the change in volume per unit change in pressure gradient between the pleura and alveoli (transpulmonary pressure) it can be static or dynamic
What is static compliance?
It is a measure of distensibility. A lung of high compliance expands more at a constant transpulmonary pressure.
What is dynamic compliance?
It is measured during tidal breathing after inspiration and expiration when lungs are stationary. It is only less than static compliance when there is respiratory obstruction
What is DLco?
It measures the interaction of: alveolar SA, alveolar capillary perfusion, alveolar capillary interface, capillary volume, Hb concentration and the CO and Hb reaction rate. It is the rate of uptake of CO/pressure of CO
How is the DLco measured?
It is a single 10 second breath-holding technique. The alveolar sample is obtained & DLco is calculated from the total volume of the lung, breath-hold time and initial and final [CO]
How is flow measured?
Anemometer; hot wire detector; baffle; pneumotachograph
What does an anemometer do?
It counts vane rotation
What does a hot wire detector do?
It measures cooling, which is proportional to flow
How does a baffle work?
The distance the baffle moves is proportional to flow
How does a pneumotachograph work?
Air flows through lots of thin tubes, the pressure is measured in two places. The drop in pressure is proportional to flow
Why should you measure lung function?
To make a diagnosis; to monitor a known disease (progress of the disease, effect of treatment, effect of exposures); disability evaluation
What are the good points about FEV1?
It is highly reproducible, it is a good overall assessment of lung health, it is a good overall assessment of mortality risk. Over 80% is normal
What does FVC indicate?
A value of under 80% indicates airway restriction. But it is less reproducible than FEV1
What is the FEV1/FVC ratio?
It measures the percentage of total lung volume exhaled in the first second. Less than 70% is abnormal.
What does FEV1/FVC indicate?
A low FEV1/FVC (less than 70%) shows airway obstruction. A normal ratio and low FVC shows airway restriction
What are the different types of cholinergic receptors?
Nicotinic (ganglia, neuromuscular junctions) and muscarinic (parasympathetic, M1,2,3,4,5)
What are the types of adrenergic receptors?
Alpha and beta(1,2,3)