Respiratory Flashcards
What are the functions of the nose?
Air modifying: Temperature Humidity Filter function Defense function
What structures are in the upper respiratory tract?
Nasal cavity
Pharynx
Larynx
What structures are in the lower respiratory tract?
Trachea
Primary bronchi
Lungs
What is the first defense in the respiratory tract?
Nasal hair
What are turbinates?
Folds in the nasal cavity to increase the surface area. Creates the superior, middle and inferior meatus’
What are the four sinus’ in the face?
Frontal
Maxillary
Ethmoid
Sphenoid
Where are the frontal sinus’? And it’s nerve supply?
Within the frontal bone
Midline septum
Nerve supply- opthalmic division of trigeminal nerve
What is the shape and the borders of the maxillary sinus’?
Pyramidal shape. Behind medial part of cheeks Base- lateral wall of nose Apex- zygomatic process of maxilla Roof- floor of orbit Floor- alveolar process
What bone is the maxilla sinus found?
Within body of maxilla bone
Where does the maxillary sinus drain into?
Middle meatus (space between two terbinates) The opening is called the hiatus semilunaris
What drains into the hiatus semilunaris?
Frontal sinus
Maxillary sinus
Anterior ethmoidal sinus
Where are the ethmoid sinus’ found? And what do they drain into?
Between the eyes. Drain into the semilunar hiatus of the middle meatus.
What is the nerve supply of the ethmoid sinus?
Opthalmic and maxillary divisions of the trigeminal nerve
What is the nerve supply of the maxillary sinus?
Maxillary division of the trigeminal nerve
Where is the sphenoid sinus found?
Inferior to optic canal, dura and pituitary gland. Medial to the cavernous sinus
What is the nerve supply of the sphenoid sinus?
Opthalmic division of the trigeminal nerve
Where does the sphenoid sinus drain into?
The sphenoethmoidal recess, lateral to nasal septum
What are the three divisions of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx (hypopharynx)
Where do the eustsachian tubes empty into?
Nasopharynx (in the respiratory tract)
Where does the nasopharynx end?
At the end of the soft palate/ start of the oropharynx
What are the names of the two folds found in the oropharynx?
Palatoglossal folds
Palatopharyngeal folds
What sits between the palatoglossal and palatopharyngeal folds?
Tonsils
What is the larynx also known as?
Voice box
What are the three double cartilages of the larynx?
Cuneiform
Corniculate
Arytenoid
What are the single cartilages of the larynx?
Epiglottic
Thyroid
Cricoid
What innervates the larynx?
Superior laryngeal nerve and recurrent laryngeal nerve. These are both branches of the Vagus CNX nerve
What does the recurrent laryngeal nerve innervate?
All muscles of the larynx apart from the cricothyroid muscle.
What do the recurrent laryngeal nerves innervate?
All muscles of the larynx apart from the cricothyroid muscle.
What is a key difference between the left and right recurrent laryngeal nerves?
Right side- branches from the vagus at subclavian artery, hooks underneath and ascends to larynx
Left side- branches from the vagus, hooks under the arch of the aorta, ascends to the larynx
What are the three single laryngeal cartilages?
Epiglottis
Thyroid
Cricoid
What innervates the cricothyroid muscle?
External branch of the superior laryngeal nerve
Which laryngeal nerve loops under the arch of the aorta?
Left recurrent laryngeal nerve
What is the approx cardiac output value per min?
5 litres per min
What is the difference between ventilation and perfusion?
Ventilation: the exchange of gas from the atmosphere to the lungs
Perfusion: the blood supply to the lungs area
Where does the trachea run from/to?
Larynx to carina (T5)
What type of cells line the trachea?
Pseudo stratified, ciliated, columnar epithelium
What is the carina?
The ridge of cartilage that divides the trachea into the right and left main bronchi
Which bronchus is more vertically disposed?
Right main bronchus
How many lobes does the right lobe have?
3.
Upper, middle, lower.
Which lung is bigger?
Right
How many lobes does the left lung have?
2
Upper and lower lobe
What is the lingula of the lung?
A short segment found in the upper lobe of the left lung. Thought to be a remnant of a left middle lung
What are the three types of bronchiole?
Lobular
Terminal
Respiratory
What cells make up alveolar cell walls?
Type I pneumocytes
What cell types secrete surfactant in the alveoli?
Type II pneumocytes
What do type I and II pneumocytes do and where are they found?
Found in the alveoli
Type I- make up the alveolar wall
Type II- secrete surfactant
What are the two layers of the pleura of the lungs?
Visceral pleura- attached to the lung
Parietal- attached to the internal chest
What is the difference in nervous info between the two layers of the lung pleura?
Parietal pleura has pain sensation
Visceral only has autonomic innervation
What does the parietal pleura attach to?
The thoracic wall and the visceral pleura
If putting a needle into the lungs, which area needs to be anesthetised?
The parietal pleura- only this layer has pain sensation
How many orders of branching of blood supply in the lungs are there?
17 orders of branching
The airway and blood vessel run together to the alveoli. What is this group of vessels called?
Bronchovascular bundle
How many litres of air is moved via the respiratory per min?
5 litres per min
What needs to be created for air to be inhaled?
A negative intra-alveolar pressure is required to draw air in
What nerve roots innervate the diaphragm?
Phrenic nerve- from 3/4/5
C 3/4/5 keeps the diaphragm alive
What nerve supply the the intercostal muscles?
Thoraco- lumbar nerve roots at each intercostal muscle
What is the total combined surface area for gas exchange?
50-100m2
What is dead space referring to in ventilation?
Areas of the respiratory system the don’t contribute to gas exchange.
What two types of dead space contribute to the overall term ‘physiological dead space’?
Anatomic- approx 150mls of air not contributing to gas exchange e.g in trachea
Alveolar- approx 25mls
Combined these factors make up the physiological dead space (175mls)
Approximately how many capillaries are there per alveolus?
~1000 capillaries
What occurs if there is a low oxygen (hypoxic) area in the lungs?
Hypoxic mediated pulmonary vasoconstriction occurs. I.e areas where there is little oxyge in the lungs, blood is deviated away from there to somewhere with more O2 so more oxygen can be absorbed from somewhere else
What is the nomenclature difference for arterial and alveolar CO2?
Arterial- PaCO2
Alveolar- PACO2
(this is the same variation for O2 partial pressures too)
What what does PAO2 represent?
Partial pressure of alveolar O2
What does PaCO2 represent?
Partial pressure of arterial CO2
What does PiO2 represent?
Pressure of inspired O2
What nomenclature represents CO2 production?
V.CO2 (dot is supposed to be above the V)
What does V.A (dot is supposed to be above the V) represent?
Alveolar ventilation
Hyperventilation causes more CO2 to be released, what affect does this have on the blood and body?
Causes blood to become more alkali. Can cause fainting
What is the alveolar equation?
PAO2 =PiO2 - PaCO2 / R
R = respiratory quotient, usually 0.8
What fissure is found in both lungs?
Orbital fissure
What fissure is only found in the right lung?
Horizontal fissure
What are the three surfaces of the lung?
Mediastinal surface
Diaphragmatic surface
Costal surface
Which surface of the lung is the hilem of the lung found?
Mediastinal surface
What and where is the cardiac notch?
Anterior border of the left lung. Created by the apex of the heart
What structures are found at the lung root/hilum?
Bronchus Pulmonary artery 2 Pulmonary veins Bronchial vessels Pulmonary plexus of nerves Lymphatic vessels
What blood vessel supplies the bronchi, lung roots, visceral pleura?
Bronchial arteries- arise from the descending aorta
What vessels supply venous drainage to the bronchi structures at the root of the lung?
Bronchial veins
Where do the bronchial veins drain into?
Right- into azygous vein
Left- into superior intercostal vein/ accessory hemiazygous vein
At what vertebral level does the trachea bifurcate?
T4/5
What nerve provides sensory innervation to the trachea?
Recurrent laryngeal nerve
What muscles supports the two points of the cartilage C in the trachea?
Trachealis muscle
What is the blood supply to the trachea?
Tracheal branches of the inferior thyroid artery
What nerve innervates the bronchi?
Pulmonary branches of the vagus nerve
What is Dalton’s Law?
Pressure exerted by each gas is independent of surrounding gases. This is because the gas particles are so far apart from eachother that each gas types doesn’t affect eachother. The total pressure of a system is therefore a combination of all the individual partial pressures
What is Boyle’s Law?
Pressure of a fixed gas in a container is inversely proportional to its volume
What is Henry’s Law?
Dissolved gases in a liquid are proportional to it’s partial pressure above the liquid. I.e. the gaseous and liquid partial pressures of an element must be the same
Define inspiratory reserve volume
Amount of air in excess tidal inspiration that can be inhaled with maximum effort
Define inspiratory reserve volume
The amount of air in excess tidal expiration that can be exhaled with maximum effort
Define residual volume
The amount of air that remains in the lungs after max exhalation. Keeps alveoli inflated
Define vital capacity
Volume of air that can maximally be exhaled after maximum inhalation
Define functional residual volume
Amount of air remaining in the lungs after normal tidal expiration
Define inspiration capacity
Maximum amount of air that can be inhaled after normal exhalation
Define total lung capacity
The maximum volume of air the lungs can contain
Define tidal volume
The amount of air inhaled or exhaled in one breath. ~500ml a breath
Define FEV1
Forced expiratory volume in the first second.
What is the difference between airway obstruction and airway restriction?
Obstruction- leads to people not being able to expel as much air from the lungs due to narrowing of airways
Restriction- patient struggles to expand the lungs enough during inspiration. Often due to stiffened tissue, weakened muscle or damaged nerves
What are some common conditions of obstructive lung disease?
Asthma
COPD
Cystic Fibrosis
What is restrictive lung disease?
Lungs can’t expand enough during inspiration. Often due to stiffened tissue, weakened muscle or damaged nerves
What is obstructive lung disease?
Patient can’t expel as much air from the lungs due to narrowing of airways so increased air resistance
What are the FVC values for patients with airway restriction and airway obstruction?
Forced Vital Capacity.
Obstructive- normal, takes longer but same volume (FEV1 is <70%)
Restrictive- <80%
How do I remember the difference between airway restriction and obstruction)
Obstruction - airways restrict (vowels)
Restriction- lungs can’t expand (constenants)
What are some common conditions leading to restrictive lung disease?
Obesity
Interstitial lung disease- conditions causing scarring of lung tissue
Pneumothorax (collapsed lung
What is hypoxia? And what are the 4 types of hypoxia?
O2 deficiency (lack of supply) at tissue level.
Hypoxaemia- lack of O2 in arterial blood
Anaemia- lack of haemoglobin to carry O2
Ischaemic hypoxia- insufficient blood flow hence lack of O2
Histoxic hypoxia- inability of cells to take up O2
What is hypercapnia?
An increase in PCO2 in arterial blood
What is the most common kind of hypoxia?
Hypoxemia- arterial partial O2 pressure is reduced
What are the most common causes of hypoxia?
- Hypoventilation
- Diffusion impairment
- Shunting- e.g. ventricular septal defect
- Ventilation-perfusion mismatch (most common cause of hypoxemia)
Physiologically, what happens when someone hypoventilates?
Hypoventilation- leads to increases arterial partial CO2 pressure
Failure to ventilate alveoli properly- often caused by muscular weakness (MND), obesity and loss of respiratory drive
Physiologically, what causes diffusion impairment in the lungs?
Thickening of alveolar membranes or a decrease in their SA
Causes failure of equilibrium between blood and alveolar O2 partial pressures
What are the two types of respiratory failure?
Type I- failure of O2 exchange
Type II- failure of CO2 exchange
Which singular and which paired cartilage interact to change the vocal cords?
Arytenoid (pair) cartilages rotate on the cricoid (singular) cartilage to change the vocal cords.
How many segmental branches do the right and left lung have?
Right has 10
Left has 8
What is an acinus?
The area of tissue supplied by one terminal bronchile
The pulmonary plexus provides the nerve supply to the lungs. What nerve supplies this? And at what vertebral levels do they branch?
Vagus nerve (left and right). Branch at T2-T4 ganglia of the sympathetic trunk
What is the effect of stimulation of fibres from the sympathetic trunk at the lungs?
Bronchodilation
What is the effect of stimulation of parasympathetic fibres from the vagus nerve at the lungs?
Bronchoconstriction
Which two arteries run together in the bronchovascular bundle?
Bronchus and pulmonary arteries
What is the transpulmonary pressure?
The difference in pressure between the inside and outside of the lung. (Alveoar pressure - intrapleural pressure)
What is the intrapleural pressure?
The pressure in the pleural space (also known as the intrathoracic pressure)
What is the definition of alveolar pressure?
Pressure in the pulmonary alveoli
What is the innervation of the diaphragm?
Phrenic nerve- from roots C3/4/5
Activation of motor nerves in the external intercostal nerves causes what?
Contraction of intercostal nerves resulting in upwards, outwards movement of ribs and an increase in thoracic volume
What happens to the interpleural/interthoracic prressure when the thorax expands? And what does this do to the transpulmonary pressure?
Interpleural pressure decreases.
Causes transpulmonary pressure to become more positive. Alveolar pressure decreases= oinward airflow
A positive transpulmonary pressure causes lung expansion. What process opposes this?
Elastic recoil by the lungs
Where in the respiratory tract has the most air resistance?
Trachea- this is because overall smaller tracts add up to having a greater surface area so have less resistance
How many alveoli are there per lung?
300 million
There is always a small alveolar- atrial O2 gradient of about 5mmHg, why is this?
Ventilation-perfusion mismatch due to gravitational effects of the human upright posture. (Higher PO2 in alveoli than arteries)
The pulmonary homeostatic responses to oxygen presence are different to that of the systemic system. How is this?
In the lungs, if either the alveoli or blood supply became hypoxic, those areas would restrict to take blood flow and oxygenated blood to areas better ventilated/perfused. In the systemic system, the opposite would happen
How many oxygen molecules can bind to a haemoglobin molecule?
4
Heamoglobin can exist in two forms. What are they?
Deoxyhaemoglobin (Hb)
Oxyhaemoglobin (HbO2)
What is the shape of the oxygen dissociation curve and why is this?
Sigmoid shape. Each O2 molecule binds to a haemoglobin subunit subqeuntially and each combination facilitates the next O2 to bind mean it will more easily bind.
As the PO2 increases between …….. and …….. mmHg, it very rapidly combines with haemoglobin. After this ………% saturation, O2 binds more gradually with an increase in O2.
10 to 60 mmHg
90% (so at 60mmHg, 90% of haemoglobin is combined with O2. With a further increase in O2, only a small increase in O2 binding- hence plateau in curve)
Why is the plateau in the O2 dissociation curve so important in human survival?
At times of low atmospheric pressure (e.g. altitude) or reduced lung function, oxygen saturation will only reduce slightly
What happens to the O2 dissociation curve with high temp or a decrease in pH?
Shifts to the right- so at any PO2, haemoglobin has LESS affinity for O2. (If it shifts to the left, opposite effect. Lefts=Locks in more O2)
Why during high temp or acidity in the blood, does haemoglobin have a lower affinity for O2?
So that O2 more easily dissociated and moves into the tissue capillaries
What metabolically occurs when CO is inhaled?
CO has 200x greater affinity for haemoglobin than O2. Competes for O2 binding sites. Also moves O2 curve to left; decreases unloading of O2 into tissues
PaCO2 is inversely related to alveolar ventilation. What equation shows this?
PaCO2 = kVCO2/ VA
k=0.863
What three ways can CO2 be carried in the blood?
Carbaminohaemoglobin- CO2 bound to haemoglobin. ~23%
CO2 dissolved in plasma- ~10%
As bicarbonate (HCO3-)- ~60-65% (carbonic anhydrase enzyme catalyses this reaction of CO2 into bicaronate ions and protons)
Briefly describe the bicarbonate buffer system as a transport mechanism to release CO2 and including the use of carbonic anhydrase.
H2CO3 –> HCO3- + H+ (w/o enzyme)
HCO3- leaves erythrocyte via transporter that exchange a HCO3- for a Cl- (maintain electroneutrality). H+ binds to deoxyhaemoglobin so only little H+ left in blood sooo venous blood is only slightly more acidic. In lungs, oxygen binds which releases the H+ from tissues. H+ + HCO3- –> H2CO3 again. With carbonic anhydrase, HCO3- + H+ –> CO2 + H2O (CO2 is expired).
What is the name of the condition where there is increased H+ in the blood? And how does this occur?
Respiratory acidosis.
Hypoventilation = inadequate ventilation so CO2 can’t be excreted properly. PaCO2 increases so H2CO3 increases and increase in H+ conc
What occurs when a patient has respiratory alkalosis?
Hyperventilation means over ventilation so too much CO2 excreted and decrease in PaCO2 and H+ conc
What does the Henderson- Hasselbalch equation calculate?
Can be used to calculate the pH of a buffer solution
Which area of the brain controls breathing?
Medulla oblongata
What are two types of pulmonary stretch receptors?
Slowly adapting stretch receptors
Rapidly adapting stretch receptors
What do the peripheral chemoreceptors detect and what is there response?
Decrease in PaO2 and increase in arterial H+ conc. Stimulate carotid sinus nerve, that input at medullary inspiratory nerves
About what PaO2 will peripheral chemoreceptors cause change?
60mmHg. Normal values are 75-100mmHg, but O2 transport levels don’t really change until below 60mmHg.
Where are the central chemoreceptors found? And what stimulates them?
Medulla oblongata. Increased H+ conc of CSF. PaCO2 can also influence CSF pH
What is the difference between type I and type II respiratory failure?
Type I- only one thing affected. Low O2 OR High CO2.
Type II- two changes, low PO2 and high PCO2
What is the most common causes of type I and type II respiratory failure?
Type I- pulmonary embolism- ventilation perfusion mismatch
Type II- hypoventilation
What are the two types of circulation in the lungs?
Pulmonary and bronchial circulations
Where circulation system does bronchial circulation come from? And what % of this output?
Systemic output
2% of left ventricular output
Where in the adrenal gland is adrenaline released from? What effect does adrenaline have in the lungs?
Adrenal medulla.
Adrenaline causes bronchodilation
What type of neurons release ACh?
Cholinergic neurons
Name the most common types of receptor?
Cholinergic Nicotinic Muscuranic Adrenergic: - Alpha-adrenergic - Beta-adrenergic * Beta-2 found in lungs
What is the most common type of muscarinic receptor in the lungs?
M3 receptor. ACh binds causing bronchoconstriction
What type of adrenergic receptor is found in the lungs? What binds to it and it’s effect?
Beta-2 adrenorecptor.
Noradrenaline or adrenaline bind causing bronchodilation
What are the two types of receptor ligands?
Agonist- binds and activates receptor
Antagonist- blocks the effect by competing
In summary, which is the main parasympathetic neurotransmitter in the lungs, its receptor and its effect?
NT: Acetyl Choline (ACh)
Receptor: Muscarinic 3 (M3)
Effect: BronchoConstriction
In summary, which is the main sympathetic neurotransmitter in the lungs, its receptor and its effect?
NT: Noradrenaline (acts on adrenal gland to release adrenaline)
Receptor: Beta-2-adrenoreceptor
Effect: BronchoDilation
What type of epithelium is respiratory epithelium?
Ciliated pseudostratified columnar epithelium
What separates the epithelium and underlying connective tissue in the lungs?
Basement membrane
Where are the cough reflex receptors found?
Larynx
Trachea
Bronchi
How does a cough occur?
Epiglottis and vocal cords shut tightly trapping air in lungs
Abdominal, intercostal muscles contract forcefully and also press on diaphragm
Pressure rises to 100mmHg +
+ve intrathoracic pressure narrows trachea
Vocal cords and epiglottis suddenly open widely
Pressure difference causes rapid air flow out
What commonly used substance inhibits the cough reflex?
Alcohol
What is airway mucus made up of?
A viscoelastic gel containing water, carbohydrates, proteins and lipids (and trapped microbes)
What produces mucus? And where is this structure found?
Goblet cells. Found in airway surface epithelium and submucosal glands
What is the phenomenon of mucous removal known as?
Mucociliary escalator. Mucous and trapped contents are moved up respiratory tract to the pharynx where swallowed. Air particles are exhaled
What are the two layers of mucus found in the respiratory tract?
Superficial gel/mucous layer Surfactant layer (liquid/periciliary)- bathes the cilia
Define bronchial asthma
A chronic inflammatory disorder characterised by hyperactive airways leading to episodic reversible bronchorestriction hence reduces air reaching lungs
What law explains velocity through a tube? E.g resistance through an airway. And what factors affect this?
Poiseuille's Law. Viscosity Pressure gradient Length Diameter
What is Poiseuille’s Law used to calculate in respiratory medicine?
The air resistance depending on the diameter of the airway
What is Poiseuille’s Law formula?
R = 8ƞl / πr^4. (R= resistance, ƞ = viscosity, l = length).
What does Boyle’s Law state? And a formula to represent this?
Pressure and volume are inversely proportional.
P1V1 = P2V2
What law states the pressure and volume are inversely proportional to eachother?
Boyle’s Law
What is humoral immunity?
Immunity that occurs extracellularly i.e in the blood/plasma and NOT in cells
What is the purpose of cytokines?
Proteins that act as signalling molecules between leukocytes and tissue cells
What does Ohm’s Law state?
Airflow = pressure gradient/resistance
What are white blood cells also known as?
Leukocytes
What specialist tissue resident macrophages activate acute inflammation of the lungs?
Kupffer cells in liver
Alveolar macrophages in lungs
Histiocytes in skin and bone
What is the most common type of pulmonary macrophage?
Alveolar macrophage- 93% of pulmonary macrophages
What do alveolar macrophages do in response to foreign material?
Phagocytosis
Secrete toxic chemicals
Present antigens to T helper cells
Secrete cytokines
What do alveolar macrophages arise from and where are they produced?
Monocytes in the bone marrow. Transform into macrophages when entering tissues
Where are the respiratory control centers in the brain?
Medulla- sends signals to muscles involved in breathing
Pons- controls rate of breathing
What does the ventral respiratory group control?
Forced exhalation and can increase the force of inspiration
What does the dorsal respiratory group control?
Mostly respiratory movements and there timings
