Respiratory Flashcards
When would there be blunting of the costophrenic angle?
Pleural effusion
At what level is the carina?
T4 and T5 (second rib)
What is the division of the upper and lower respiratory tracts?
Vocal cords
Where do the intercostal nerves originate?
Anterior rami of spinal nerves T1 to T11
Which bronchus is shorter and fatter?
Right
Where would you place a chest drain?
Above the rib in the 5th intercostal space on the midaxillary line
What are the three layers of intercostal muscle?
External
Internal
Innermost
How many true ribs are there?
Seven
What are the three movements of normal ventilation?
Vertical
Anteroposterior
Lateral
What are the relationships of the structures in the hilum?
Bronchi behind
Arteries above
Veins and Phrenic nerve in front
Where do intercostal veins drain into?
Azygos system of veins or the internal thoracic veins, which connect to the brachiocephalic veins in the neck
What is transudate?
Excess tissue fluid leaking into the pleural space, as a result of fluid transmitting across the capillary membrane.
Has a low protein content.
Which nerve innervates the sternocleidomastoid muscle?
Spinal accessory nerve
What is the order of the intercostal nerves and vessels (top to bottom)?
Vein
Artery
Nerve
How long does a red blood cell spend in the capillary network of the lungs?
0.75 seconds
From which vessels do the intercostal arteries arise?
Aorta and internal thoracic arteries, which originate from the subclavian arteries
What is an empyema?
Pus in the pleural space
What is a chylothorax?
Lymph in the pleural space
Where is a tracheostomy performed?
On the thyroid gland (second/third tracheal ring)
Where does the thyroid gland sit?
On the second/third tracheal cartilages in a butterfly shape
What is the anatomical dead space?
And how large is it?
From the trachea to the terminal bronchioles, where no gas exchange takes place
About 150ml
What is the lateral movement of the ribs also known as?
What muscles does it use?
Bucket-handle action
Intercostal muscles
What would a lowered FEV1/FVC ratio (lower than 75%) with a normal FVC signify?
Obstructive lung disease
Between which two muscles do the intercostal nerves and vessels pass?
Internal and innermost
How many divisions of the bronchioles are there?
23
What is the mucociliary escalator?
Movement of cilia in the lung to remove mucus and bacteria
What are the muscles of expiration?
Rectus abdominis
Latissimus Dorsi
What are the forces of Starlings principle?
Hydrostatic pressure of blood
Hydrostatic pressure of interstitial fluid
Osmotic pressure of blood
Osmotic pressure of interstitial fluid
Which of the intercostal muscles are used during expiration?
Internal
What are the three parts of the rib?
Head
Neck
Body
Which tends to be bilateral: exudate or transudate?
Transudate, due to it usually being systematic
What level is the thyroid cartilage on?
C4 and C5
What are the four regions of the parietal pleura?
Apical
Mediastinal
Costal
Diaphragmatic
What can cause exudate in the pleural space?
Result of inflammation: Pneumonia TB Malignancy Pulmonary Infarction Collagen vascular disease
What is exudate?
Proteinaceous fluid with polymorphs and has a high level of protein.
Due to vessels becoming leaky and allowing fluid and contents through into pleural space
What is the pulmonary ligament?
A loose fold of pleura that hangs down from the hilum
What is the normal FEV1/FVC ratio?
Between 75 and 80%
What are the three common COPD?
Asthma
Emphysema
Chronic bronchitis
Name three causes of transudate in the pleural space.
Cardiac failure
Nephrotic syndrome
Hepatic failure
How large is the respiratory zone and what does it consist of?
2.5-3 litres
From terminal bronchioles to distal alveolus
Which of the intercostal muscles are used during inspiration?
External
How would a restrictive disorder be shown in spirometry?
A normal FEV1/FVC ratio, but dramatically reduced FVC
What is bronchiectasis?
Long term condition where the airways become abnormally widened, leading to a build up of excess mucus, making lungs vulnerable to infection
What is an acinus?
An anatomical unit that is a portion of the lung distal to a terminal bronchiole
By which mechanism does inspired air travel down to the terminal bronchioles?
Through bulk flow
What is the dominant mechanism of ventilation in the respiratory zone?
Diffusion of gas, due to forward velocity of gas being so small by the time it gets to the respiratory zone
Which cells of the lung produce surfactant?
Type II pneumocytes (cells)
What does Fick’s Law of Diffusion state?
The amount of gas that moves across a sheet of tissue is proportional to the area of the sheet, but inversely proportional to its thickness
How does Bohr’s equation measure physiological dead space?
By measuring the volume of lung that doesn’t eliminate carbon dioxide
How does Fowler’s method measure anatomical dead space?
By measuring the volume of the conducting airways
Do anatomical and physiological dead space vary?
Not in normal subjects, though in some lung diseases physiological dead space will be increased
What are the regional differences in ventilation?
Lower regions of the lungs ventilate better than the upper zones
What causes the difference in regional ventilation of the lungs?
Gravity
What is the difference in pressure between the pulmonary circulation and the systemic circulation?
The pulmonary circulation is much lower.
Mean pressure in pulmonary artery = 15mmHg
Mean pressure in aorta = 100mmHg
What is the difference in overall distribution of pressure between the pulmonary and systemic circulation?
The distribution of pressure is more even throughout the pulmonary circulation.
In the systemic circulation there is a rapid drop between arteries and veins
What is the difference between pulmonary vascular resistance and systemic vascular resistance?
Pulmonary vascular resistance is 1/10th that of systemic.
Compatible with distributing blood in a thin film
What two mechanisms cause a decrease in pulmonary vascular resistance in response to a slight rise in pressure? (which is principle)
Recruitment (Principle mechanism)
Distension
What is recruitment of vessels?
Blood vessels not normally collecting blood open and begin conducting blood
What is distension of vessels?
Changes in shape of the capillaries from near flattened to a more circular shape
At what lung volumes is pulmonary vascular resistance low?
After passive expiration, at the level of FRC
At what lung volume do the large vessels of the pulmonary circulation have the lowest vascular resistance?
At large lung volumes, due to the lungs expanding and pulling them open
At which part of the lungs is blood flow the lowest?
The apex
What causes the uneven distribution of blood flow in the lungs?
Hydrostatic pressure differences in the blood vessels
At what part of the lungs is vascular resistance lowest?
The base
What does the Windkessel effect do to the cardiac cycle?
Dampens the fluctuation in blood pressure and assist in the maintenance of organ perfusion during diastole when cardiac ejection ceases
In which blood vessels is the Windkessel effect seen the greatest?
Large elastic arteries, such as aorta, common carotid, subclavian and pulmonary arteries
During a history, what factors would point you towards a diagnosis of asthma, as opposed to COPD?
Never smokes Diurnal variation Exacerbating factors Nasal symptoms Family history Childhood atopy (allergies)
What is cor pulmonale?
Enlargement and failure of the right ventricle of the heart in response to increased vascular resistance or high blood pressure in the lungs
What are the two subgroups of lung cancer?
Small cell carcinoma
Non-small cell carcinoma
What are the subclassifications of non-small cell lung cancer?
Squamous cell cancer
Adenocarcinoma
Large cell (undifferentiated) carcinoma
What is the most common type of lung cancer in UK?
Squamous cell lung cancer
Where does small cell lung cancer arise from and what can this result in?
Neuroendocrine cells of bronchial tree
Can result in ectopic hormone production
What are the common local effects/symptoms of lung cancer?
Cough Breathlessness Haemoptysis Wheeze Hoarse voice Recurrent infections
What is the result of a bronchial carcinoma invading a phrenic nerve?
Ipsilateral paralysis of the hemidiaphragm
What is the common metastatic nodal spread of lung cancer?
Mediastinal
Cervical
Axillary
Intra-abdominal
Which organs does lung cancer commonly metastasise to?
Liver
Bone
Adrenal glands
Brain
When conducting a CT to determine the extent of lung cancer, which organs should be included in the investigation?
Liver
Adrenal glands
How would you obtain a biopsy for a central lung cancer?
Fibre optic bronchoscopy
How would you obtain a biopsy for a peripheral lung cancer/lesion?
Percutaneous aspiration under CT guidance
What investigation is used in staging of lung cancer to visualise mediastinal nodes?
Endobronchial ultrasound
In which lung cancer type and stage can surgery be considered with curative intent?
Non-small cell lung cancer - stages I, II and in selected IIIa
What investigation is used to determine extent of nodal involvement and highlighting distant metastases?
PET scan
In healthy individuals what is the main drive for respiration?
Arterial pH
What is the rate of oxygen flow to the tissues?
250mL/min
What do the central and peripheral chemoreceptors detect?
Arterial PCO2 and pH (Central and peripheral) Arterial PO2 (peripheral)
What is the most important factor in chemical control of ventilation?
PCO2
How much does respiration increase for a rise in alveolar PCO2?
15-25L/min for each kPa rise in alveolar PCO2
What is normal alveolar PCO2?
5.3kPa
What is normal alveolar PO2?
13kPa
Which chemoreceptor is thought to control the majority of the respond to CO2 in humans?
Central chemoreceptor near the ventrolateral surface of medulla
What two types of cells does the carotid body contain?
Glomus (type I) cells
Sheath (type II) cells
What is the function of glomus cells?
Responsible for peripheral chemoreception
What is the function of sheath cells?
Protect and support glomus cells
Where is the central pattern generator (for breathing) and what does it contain?
Pons and medulla
Contains inspiratory and expiratory neurons
What part of the respiratory centre is in the pons and what is it involved in?
Pneumotaxic centre - eupnoea and mediating responses to lung receptor stimulation
What is thought to be the probable source of rhythm of breathing?
Cycling or switching due to reciprocal inhibition and ‘off switches’ within networks of central respiratory centre in pons and medulla
