What is the partial pressure of O2 and CO2 in arteriole blood?
PAO2: 13.3 kPa
PACO2: 5.3 kPa
What is the partial pressure of O2 and CO2 in atmospheric air?
O2: 0.209 (20.9%)
CO2: 0.0004 (0.04%)
What does disease burden and relative rankings depend on?
The parameter studied and the population studied - mortality, morbidity (either hospital admissions OR years lived with disability), uniformity across world/country
What is the UK's leading disease burden vs the leading actual killer?
Low back pain vs Ischemic heart disease
What is the mortality rate of respiratory diseases?
1 in 5 die in the UK
What has happened to the death rate of COPD in recent years?
It has risen dramatically, predicted to be in top 3 causes of mortality by 2020
What is the biggest cancer killer in the UK?
Lung cancer - more women die from lung cancer than from breast cancer
Some facts about lung cancer in UK:
45,000 new cases per year,
What is happening to the prevalence of smoking?
It is decreasing but more women are smoking now - 21% men and 16.5% women smoke
What are the 4 things to consider when diagnosing a patient with a resp disease?
1. Infectious 2. Pulmonary vascular disorder 3. Small lung disorders 4. Airways diseases
Give me an example of an infectious resp disease
TB - rates have been rising again especially in London
Give me an example of a pulmonary vascular disorder
Pulmonary emboli - clots from legs/pelvis can complicate mobility and become fatal - single biggest cause of maternal death associated with childbirth
Give me 2 examples of a small lung disorder due to disease outside of lung
Mesothelioma caused by Asbestos - increasing rapidly, with peak in 10ish years
Obesity - ^ resp workload and resp dysfunction and associated with ^ risk of asthma and sleep related breathing disorders
Give me an example of an airways disease with a localised obstruction:
Sleep apnoea - leads to six times normal risk of having a road accident - can't breath for 45 out of 60s during sleeping, so wake up and get unrestful sleep
Some facts about COPD:
920 admitted to hospital - 10.4% died, 19.1% readmitted after discharge within a month, 34.2% too breathless to leave the house
Give me an example of a small lung disorder due to disease within the lungs:
Idiopathic Pulmonary Fibrosis - median survival rate is 3 years, 35% increase in diagnosis
What is the main issue with resp diseases?
Most of them aren't diagnosed well enough, if at all
What are the main symptoms that reflect lung disease?
Breathlessness, coughing, sputum production, chest discomfort, hoarseness, etc
What is the problem with lung disease symptoms?
Could be due to many reasons - eg: Breathlessness: Lung/heart/pulmonary vascular/neuromuscular disease, systemic disorders etc
What are the main processes that are debilitated by these illnesses?
Function of lungs is gas exchange - resting adult needs 250ml O2/min which is more than acquired by diffusion
How do different diseases interfere with gas exchange?
COPD: toxic effect paralyses cilia so can't sweep mucus and secretions interfere with calibre of airway
How can the calibre of the airway be changed?
Mucus isn't swept away so builds up, thickening of membrane, thinning of membrane and loss of supportive tissue around airway
Why are spirometers important?
Can determine what kind of lung disease - between small lung disease vs obstructive disorders
What are the main structure of the resp system?
Nasal cavities, sinuses, pharynx, larynx, tracheobronchial tree, lungs, diaphragm
What is the role of the nasal cavity?
To warm and moisten the air that we breathe in
How is the nasal cavity innervated?
By 2 types of innervation - 1) sensory/somatic from CNV: Lower half by maxillary divison and upper half by ophthalmic division
2) olfactory nerves that lie above the nasal cavity, close to the brain
What are the names of the three major ridges in the sinuses?
Inferior, Middle and Superior Concha, with inf being the biggest
What are the 4 sinuses?
Frontal (between the eyebrows), Ethmoidal (between the eyes - air cells), Sphenoidal (under the pituitary), Maxillary (under the eyes - largest and main ones)
What is the debilitating factor of the maxillary sinus and why is it a problem?
The drainage opening is at the top of the sinus, so drainage of mucus is difficult, hence infections can occur more easily
Why do dentists have to be careful when removing teeth?
There is very little space between the root of the tooth and the maxillary sinus, so erosion of the layer could cause a hole in the maxillary sinus
What do the ethmoidal sinuses and the separation between the brain and nose do?
It acts as an insulation layer, to keep the brain and the eyes from experiencing any sudden change in temp from the air inhaled
What is the nasal septum?
Its the bone and cartilage that separates the nostrils
What are the 3 sections of the pharynx?
Nasopharynx, Oropharynx, Laryngopharynx
Where is the nasopharynx section?
Extends from back of nasal cavity to bottom of the tongue
Where is the oropharynx?
From below the tongue to the epiglottis
Where is the laryngopharynx?
From the epiglottis to the beginning of the oesophagus/entrance to larynx
What is the larynx?
The voice box - holds the vocal cords
What is the structure of the larynx?
Hyoid bone, thyrohyoid membrane, thyroid cartilage, cricothyroid ligament, cricoid cartilage
Where is the larynx situated?
Anterior of the neck, can feel it as 'Adam's apple'
Where is the opening of the larynx?
Situated posteriorly to the thyroid cartilage
How is the thyroid bone adapted for its function?
It is open at the back, so it is c-shaped up until the cricoid cartilage which goes all the way around
What are the vocal ligaments and what do they do?
They are infoldings of the membrane and they open when we breathe and close when we talk, so air passes through, phonating the air
What is the difference between phonation and vocalisation?
Phonation is done by the larynx and changes pitch and volume of the air
Vocalisation is the movement of tongue, cheeks, mouth to make words
What is the structure of the trachea?
C-shaped cartilage ring with epithelium on the inside. Between trachea and oesophagus exists the Trachealis muscle
Where does the tracheobronchial tree begin?
Bifurication is at T4-5 around the sternal angle
What kind of bifurcation is it?
It's asymmetrical, with RHS straighter and shorter than left as it moves to the right due to aortic arch
How does the bronchial tree separate?
Primary, lobar, segmental bronchi - all have cartilage but it decreases as it goes down the levels
What's after the segmental bronchi?
Bronchioles which are made from smooth muscle (no cartilage)
Where do bronchioles terminate?
In the alveoli
Where do the viscera and parietal pleura meet?
At root of lung and they are kept lubricated by surfactant
Where do the lungs and the pleura reach on the body?
The pleura reaches 2 ribs below, so 6 and 8th respectively on midclavicular line
Why is there more space for the pleura below the lungs?
To allow space for lungs to expand if needed
What is the pulmonary ligament?
An extension of the pleura, allowing space for expansion
What grooves are present on the left lung?
Left subclavian artery (top closest to apex), left brachiocephalic vein, descending aorta (and arch), cardiac impression and oesophagus (in front of aorta)
What grooves are present on the right lung?
Subclavian artery, subclavian vein, svc, ivc, azygos vein (arches round) and oesophagus
What 6 things are present in the hilum?
Pulmonary arteries (deO2), veins (O2), lymph nodes, bronchi, pulmonary plexus and arterioles
What are bronchopulmonary segments?
The smallest bit of the lungs that can function independently, as it has its own blood supply, air supply and innervation
What drives oxygen across the blood-air barrier?
Partial pressures - PO2 Air = 100 mmHg, PO2 blood = 40 mmHg
Why is a lymphatic system important for the lungs?
The lungs are in contact with the outside air, so need fast access to immune system
Where is the diaphragm positioned?
Lower edge attached at costal margin, centre of dome bulges up due to pressure difference between abdomen and pleural cavities up to 5th intercostal space
What is the structure of the diaphragm?
Tendon sheet in the middle, with muscle surrounding it
How does the diaphragm contract?
The outer muscle contracts, stretching the tendinous sheet, also attached to pericardium, so heart moves along with it
What are the three tubes that pass through the diaphragm and where do they pass through?
IVC - through the tendinous tissue at T8, Oesophagus through muscular folding at T10, aorta between diaphragm and spine at T12
What is the mnemonic for the 3 hiatuses of the diaphragm?
I 8 10 E A 12 "I ate 10 eggs at 12" - IVC at T8, Oesophagus T10, Aorta T12
Where does the phrenic nerve originate?
What does the phrenic do?
Motor to diaphragm, so causes contraction
How do you tell the difference between vagus and phrenic nerve?
Vagus is posterior to hilum, Phrenic anterior
How do the ribs move when breathing?
Ribs expand like a bucket handle, so up - and like a water pump, so out, by turning the sternum outwards
What other important muscles are used in breathing?
The abdominals and the pelvic diaphragm