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Flashcards in Respiration Deck (55)

What is the effect of alkalosis on the CNS?

Overstimulation, which can lead to tremors.


What is the effect of acidosis on the CNS?

Depression, leading to coma and death.


What is the difference between type 1 and type 2 respiratory failure?

Type I respiratory failure involves low oxygen, and normal or low carbon dioxide levels. It is usually due to a mismatch in ventilation and perfusion.
Type II respiratory failure involves low oxygen, with high carbon dioxide. It is usually due to hypoventilation of the alveoli.


What is the difference between obstructive and restrictive pulmonary disease?

Obstructive means there is something blocking the bronchioles which makes it harder to expire the air in the chest. Forced vital capacity will not really decrease but FEV1 will significantly, so that the FEV1/FVC ratio decreases.
Restrictive means there is a decrease in compliance of the lungs so it is harder to fill the lungs with air. The FVC and FEV1 will both decrease so there will be little or no change in the FEV1/FVC ratio.


Define compliance.

The ease with which the lungs expand and contract.
Compliance is the measure of distensibility of matter and specifies the ease with which matter can be stretched or distorted.
It equals a change in volume per unit change in pressure. (Change in volume/Change in pressure.)


What factors affect compliance?

The connective tissue structure of the lungs, the production of surfactant by type 2 pneumocytes, the mobility of the ribs.


What happens if the chest wall is punctured?

Pneumothorax (air rushing into pleural cavity) which increases the pressure in the pleural cavity, causing atelectasis (collapsed lung).


Does a decrease in blood pH stimulate the central chemoreceptors to increase ventilation?

No, H+ ions can't cross the blood-brain barrier, only C02 can, so there would have to be an increase in blood pCO2 to decrease the pH in CSF and stimulate central chemoreceptors.
Therefore, only the peripheral chemoreceptors are stimulated in respiratory compensation.


Which structures contribute to the fully developed diaphragm?

Septum transversum, myoblasts from the mesoderm of the body wall, pleuroperitoneal folds, dorsal mesentery (of the oesophagus).


How does compliance relate to the elastic recoil of the lungs?

Compliance is inversely proportional to elastic recoil.


What is forced vital capacity?

The volume of gas from deepest inspiration to deepest expiration.


What is FEV1?

The maximum volume of air that can be forcibly expired in the first second after deepest inspiration.


What happens to the pO2 in the blood after haemorrhage (the amount of haemoglobin in the blood has decreased)?

The pO2 will be unchanged.


What are the main sites of the baroreceptors that detect increased blood pressure?

Aortic arch and carotid sinuses.


Why does the residual volume increase slightly in acute asthma?

It is an obstructive disease and so there is difficulty in expiration caused by bronchoconstriction.


What happens to the FRC (functional residual capacity) in obstructive diseases and restrictive diseases?

In obstructive diseases, the FRC is increased.
In restrictive diseases (like obesity) and with age, the FRC is reduced.


What is the medical term for coughing up blood?



What do the waves on the biphasic jugular venous waveform mean?

a wave = Atria contract
c wave = Cystole begins (tricuspid prolapse)
x wave = atria relaX
v wave = Ventricles prepare yourselves (atria filling)
y wave = trYcuspid opens


What's the difference between conducting and respiratory parts of the respiratory tract?

Conducting = cartilage in wall, cleanse and warm and humidify air so it's ready for gas exchange
Respiratory = soft wall, site of gas exchange, terminal bronchioles and alveoli and alveolar ducts.


What is the purpose of the dorsal respiratory group in the medullary respiratory centre?

To generate impulses to diaphragm and external intercostals in 2 second bursts during normal quiet breathing. Inactive during forceful exhalation.


What is the purpose of the ventral respiratory group in the medullary respiratory centre?

Pre-Botzinger complex acts as a pacemaker and sets breathing rhythm by determining the rate of DRG firing impulses.
Other VRG neurones are only activated in forceful breathing - innervate accessory muscles of respiration (sternocleidomastoid, scalenes, trapezius, internal intercostals, abdominal muscles)


What is the difference between the peripheral and central chemoreceptors?

The peripheral chemoreceptors are in the carotid bodies and aortic bodies, and can detect [H+], pO2, pCO2 in the blood.
The central chemoreceptors are in the medulla oblongata and detect changed in pH of CSF cause by changes in pCO2.


Name the 5 main arteries supplying the nasal septum.

Septal branch of anterior ethmoidal artery, septal branch of posterior ethmoidal artery, septal branch of sphenopalatine artery, terminal part of greater palatine artery, septal branch of nasal artery from superior labial artery.


What are the boundaries of the nasopharynx?

Choanae to soft palate.


What are the boundaries of the oropharynx?

Soft palate to bottom of the superior laryngeal aperture (epiglottis).


What are the boundaries of the laryngopharynx?

the epiglottis to the cricoid cartilage (level C6).


What is the name of the opening between the vocal ligaments?

Rima glottidis.


What is the name of the membrane which covers the vocal ligaments?

Conus elasticus.


What level does the trachea bifurcate at?

Carina = T4/T5.


What is respiratory compensation?

Hyperventilating to blow off CO2 and increase blood pH, that has been decreased by metabolic acidosis (caused by the kidney excreting too much HCO3- and not enough H+).
It is faster but more short term than metabolic compensation.
Also hypoventilation to rectify metabolic alkalosis (caused by severe vomiting and loss of HCl).


What is metabolic compensation?

The kidneys can increase the blood pH by excreting more H+ and less HCO3-, to rectify respiratory acidosis caused by insufficient expiration of CO2 (or diabetic acidosis caused by a build up of ketone bodies)
The kidneys can also decrease the pH by excreting more HCO3- and less H+ to rectify respiratory alkalosis caused by hyperventilation. Treat alkalosis by rebreathing.


What is hysteresis?

Lag in response of the body to changes of the forces affecting it - to do with the elastic recoil of lungs.


What is the function of a type 1 and a type 2 pneumocyte?

Type 1 pneumocytes - allow gases to diffuse between blood vessel and alveolus.
Type 2 pneumocytes - produce surfactant to reduce surface tension and stop alveoli collapsing.


Does an increased temperature increase respiratory rate?

Yes, sudden cold immersion can cause temporary apnoea.


Which one of visceral pain and prolonged somatic pain increases respiratory rate, and which one decreases it?

Visceral pain decreases respiratory rate.
Prolonged somatic pain increases respiratory rate.


Of acidosis and alkalosis, which one decreases synaptic transmission and which one increases synaptic transmission?

Acidosis - decreases Ca2+ so decreases synaptic transmission and leads to coma and death
Alkalosis - increases Ca2+ so increases synaptic transmission and leads to muscle spasms, convulsion and death


What is the name of the response to a mismatch in ventilation and perfusion?

Hypoxic pulmonary vasoconstriction (the mechanism that maintains V/Q ratio).
{due to gravity, perfusion is higher at the base of the lung than the apex, but ventilation is higher at the apex of the lung than the base}


What is the chloride shift?

CO2 diffuses into erythrocyte, reacts with H2O in a reaction catalysed by carbonic anhydrase to produce carbonic acid. Carbonic acid dissociates into H+ and HCO3-.
HCO3- diffuses out into the plasma and the outflow of negative ions is balanced by Cl- diffusing into the erythrocyte.
The H+ ions displace oxygen from oxyhaemoglobin to form haemoglobinic acid and release oxygen.
In the lungs the reverse chloride shift occurs.


What do you call respiratory diseases where there is a reduction in compliance?



What do you call respiratory diseases where there is a narrowing of the airways so the air is exhaled less efficiently?



What is the functional residual capacity?

The expiratory reserve volume plus the residual volume.
The volume of air left in the lungs after a normal expiration.


What is the inspiratory capacity?

The tidal volume plus the inspiratory reserve volume.


What is the total lung capacity?

The vital capacity plus the residual volume.


What is the FEV1/FVC ratio?

The proportion of vital capacity that is expired in the first second of maximum expiration.
(Decreased in obstructive diseases)


Why do people with chronic respiratory diseases have to rely on their hypoxic drive to increase respiratory rate?

Prolonged elevated CO2 decreases sensitivity to CO2 (because enough HCO3- crosses the blood-brain barrier to neutralise the increased H+ in the CSF).
So the primary respiratory stimulus is now the peripheral chemoreceptors detecting low pO2. This is why giving oxygen is dangerous as it will stop the peripheral chemoreceptors activating DRG which can result is acidosis and death due to high pO2.


What are the 3 ways carbon dioxide can be carried in the blood.

Dissolved in plasma, bound to haemoglobin as carbamino-haemoglobin, as bicarbonate ions.


What is the name of the effect where deoxygenated blood can carry more carbon dioxide?

Haldane effect.


What is the name of the effect where a higher pO2 causes haemoglobin to dissociate more easily from oxygen?

Bohr effect.


What is the difference between static and dynamic lung function tests?

Static - based only on volume
Dynamic - based on volume over a period of time


What is the difference between the measurements made by a peak flow meter, and those made by a spirometer?

Spirometer measures volume of air inspired/expired, as well as the rate at which it is inspired/ expired. Spirometer is useful to diagnose respiratory diseases.
Peak flow meter measures only the rate at which air is forced out of the lungs. Peak flow meter is useful to monitor respiratory diseases.


What is the difference between anatomically and physiologically dead space?

Anatomically dead space = conductive part of respiratory tract (no gas exchange) = pulmonary ventilation
Physiologically dead space = alveoli that are not perfused and have collapsed (increases in respiratory disease)


How do you calculate alveolar ventilation?

Tidal volume - pulmonary ventilation = alveolar ventilation


Why does the partial pressure of oxygen in inspired air decrease once it enters the body?

The air is humidified by the mucus, and so the total pressure doesn't increase but there is added partial pressure of water vapour, meaning all the other partial pressures decrease.


What is the term used to describe how the binding of oxygen to haemoglobin gets easier with each successive oxygen molecule?

Cooperativity, the haemoglobin changes from the tight conformation of deoxyhaemoglobin to there relaxed conformation of oxyhaemoglobin.


What is the molecule that binds to haemoglobin and reduces its affinity for oxygen?

2,3-bisphosphoglycerate (2,3-BPG)