CVR: Respiratory Flashcards
What two areas of the brain, not in the medulla oblongata, are involved in the control of breathing?
Pneumotaxic and apneustic centres in the pons.
What two areas of the brain, not in the pons, are involved in the control of breathing?
Dorsal respiratory group and ventral respiratory group, both in the medulla oblongata.
Which area of the medulla oblongata is predominantly active during inspiration?
The dorsal respiratory group (DRG).
What provides background ventilatory drive?
A neural network in the brainstem (central pattern generator).
Concentration of which gas predominantly influences breathing?
CO2
What do the central chemoreceptors in the brainstem detect to monitor breathing?
Hydrogen ion concentration.
How does an increase of PaCO2 cause the central chemoreceptors in the brainstem to detect increase in hydrogen ion concentration via the bicarbonate buffer system?
- CO2 crosses blood brain barrier.
- CO2 + H2O (catalysed by carbonic anhydrase) = H2CO3 (carbonic acid)
- H2CO3 dissociates = H+ + HCO3-
Where are the peripheral chemoreceptors?
Carotid bodies and aortic arch.
What do the peripheral chemoreceptors in the carotid bodies and aortic arch measure to monitor breathing?
Measure PaCO2 predominantly, but also measure PaO2 and pH.
What are the three types of mechanoreceptors in the lungs that send afferent information to the respiratory control centres via the vagus nerve?
JIS!
J receptors (juxtacapillary AKA pulmonary C-fiber receptors), irritant, and stretch.
Where are the receptors which prevent respiratory activity during swallowing?
The pharynx.
Why can x-rays be dangerous?
They are a form of ionising radiation, which can damage tissue, cells, and DNA (mutagen).
What colour are more dense structures on an x-ray? Give an example.
White. E.g. bones.
On a chest x-ray, why is the diaphragm higher on the right?
Due to the presence of the liver.
What anatomical landmark on a chest x-ray can be used to assess symmetry?
The clavicles.
Why aren’t the anterior aspects of the ribs easily visible on a chest x-ray?
They are cartilaginous.
Which view is most ideal for a chest x-ray and why; AP (anterior-posterior) or PA (posterior-anterior)?
PA (posterior-anterior); patient facing the detector, standing up.
This is because there will be a crisper image and accurate size of the heart than in AP view, and the scapulae can be protracted.
Which causes more ionising radiation for a patient, chest x-ray or abdominal x-ray?
Abdominal x-ray.
Where should you look to check for cyanosis?
Under the tongue at glossal artery.
Both Type 1 and Type 2 respiratory failure are characterised by hypoxaemia (low PaO2) due to an inability to maintain normal blood gases. What is the difference between Type 1 and Type 2 respiratory failure?
Type 1 = hypocapnia/normal PaCO2
Type 2 = hypercapnia (high PaCO2)
What causes Type 1 respiratory failure?
Many different causes, including infectious, congenital, and neoplasmic (tumour) causes.
What causes Type 2 respiratory failure?
Hypoventilation leading to hypercapnia. For example, in COPD.
Why might someone with anaemia not be cyanotic when severely hypoxic?
Cyanosis is caused by large amount of deoxygenated haemoglobin. Anaemic patient might not have enough haemoglobin to be cyanotic.
In chronic hypercapnia, such as in COPD, chemoreceptors are thought to reset. Breathing is no longer driven by increase in PaCO2 and instead driven by decrease in PaO2.
Why might giving supplementary O2 to a patient with COPD cause Type 2 respiratory failure?
If give supplementary O2 and raise PaO2, the patient might lose their ventilatory drive and hypoventilate, causing CO2 retention and hence Type 2 respiratory failure.