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Flashcards in Respiration Deck (47)
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What factors can effect pulmonary compliance?

Increase - Surfactant and Emphysema (loss of elastic tissue so its easier to stretch)

Decrease - Pulmonary fibrosis (scar tissue is harder to stretch)


Name the receptors that detect H+, CO2 and O2, and where they're found

Central Chemoreceptors - [H+] and PCO2


Peripheral Chemoreceptors - PO2

These are found in the carotid and aortic bodies


What is the parenchyma?

The functional unit of the lungs, and where gaseous exchange takes place


List the differences in the muscles used during inspiration and expiration during exercise

Inspiration - External intercoastals



Expiration - Internal intercoastals

Abdominal muscles



What stimulates the development in lung epithelium in babies?



How are the lungs emptied of fluid during birth?

There is a surge of steroids and catecholamines which activate Epithelial Sodium Channels (ENaC) These cause Na+ to leave the lungs, and take the water with them


What is meant by the neuronal control of breathing?

The automatic control by respiratroy centres in the brainstem


The lungs have various metabolic functions. What is one of the major functions in terms of the kidneys?

It activates Angiotensin 1 --> 2


Is gas exchange done in the upper or lower respiratory tract?



What role can adrenaline have on smooth muscle?

Cause it to contract/constrict


Describe Slowly Adapting myelinated fibres

These are stimulated by stretch receptors in smooth muscle (in the airways)

They causes various reflexes such as shortened inspration, the Hering-Breuer Reflex, and bronchodialation


Hering-Breuer Reflex = the promotion of exhalation after inflation (to prevent over-inhalation)


What are pleural membranes?

A double membrane that surrounds each lung, containing serous fluid (as a lubricant)

They act as a seal to ensure that if one lung collapses, the other will be ok

The fluid also allows the lungs to stick to the inside of the thorax


Explain what is meant by Ventilation-Perfusion matching

For gas exchange to be as good as possible, the ventilation of the alveoli must equal the blood perfusion

If the ratio is not equal to 1, then we need to decrease the blood flow (if one lung is not working) via vasoconstriction




Describe rapidly adapting stretch receptors (myelinated)

These are stimulated by sudden, sustained inflation, as well as irritant receptors

They causes reflexes such as coughs, bronchodialation and mucus secretion


What is the difference between Exogenous and Endogenous stimuli?

Exogenous - Noxious agents from the air


Endogenous - Inflammatory agents that are generated by the body


Describe the fluctuations in PCO2 during exercise

Ventilation increase before exercise starts, so PCO2 decreases to start with

The PCO2 then increases slowly as more CO2 is produced from exercise

Once exercise stops, PCO2 spikes due to a drop in ventilation


What are the downsides of a lung transplant?

There is a loss of lung-brain innervation

So there is a loss of the Hering-Breuer Reflex and cough stimulation


Explain how Acetazolamide, Doxapram and Caffeine work

Acetazolamide - Inhibits carbonic anhydrase to create mild acidosis --> increasing the ventilation rate

It can also lower EPO production and haematocrit


Doxapram - Closes K+ channels in the glomus cells to increase the repsiration rate


Caffeine - Stimulates non-specific parts of the CNS, including the respiratory system


Name one way in which the specilaisation of cells change as you move down lung airways

Less ciliated cells are present They also get smaller


What is meant by "binding is co-operative" in terms of haemoglobin?

As each of the 4 molecules of oxygen binds, it becomes easier for the next oxygen to bind


How do you calculate the Partial Pressure of a gas?

Also how do you calculate the RQ

P = Barometric pressure x Fraction of the gas


RQ = CO2/O2

A usual value of 0.8 represent 0.8 CO2 is used for every 1 O2


Sensory (afferent) nerves innervate epithelial cells to the brain, but what type of innervation occurs from the autonomic fibres?

Parasympathetic branches of the vagus nerve This can be both inhibitory and excitatory


List the differences between the Pulmonary and Bronchial Circulations

Pulmonary - Low [oxygen] Has a high flow rate and is complient --> so it has a large blood capacity Passes around the alveoli Blood flows from the right ventricle Its job is to allow gaseous exchange to occur and return the oxygenated blood back to the left heart

Bronchial - High [oxygen] Supplies the cells of the conducting airways with oxygen and nutrients Has a low flow rate but high pressure Blood flows from the aorta (left ventricle)


Explain the importance of the respiratory centres in the brain stem

Medulla - Contains both inspiratory and expiratory centres which stimulate intercoastal muscles

It recieves information from the periphery and Pons

The Exipratory centre is only used when exercising


Pons - Contains both the Pneumotaxic and Apeneustic Centres

The Pneumotaxic centre modifies signals in the medulla to control breathing rate and its pattern


How do coughs occur?

Irritant receptors are stimulated, which send sensroy nerve signals to the medulla, which sends motor nerve signals to the skeletal muscles

This causes the glottis to close, and intercoastal muscles to contract rapidly

The pressure increase causes the glottis to open --> causing the cough


What are the roles of mechanoreceptors and chemoreceptors in the lungs?

Mechanoreceptors detect muscle movement in the lungs (when they're stretched)

Chemoreceptors detect a change in pH, which is dependent on the [CO2]


What is surfactant? And where is it made?

A solute that when dissolved in solution reduces surface tension, mainly in the alveloi --> preventing their collapse They are made in Type 2 epithelial cells Theyre made up mainly of lipid (mostly phospholipid)


What is the purpose of the Pre-Botzinger Complex?

It creates spontaneous discharge that causes rythmic stimulation of motor nerves --> causing the contraction of the diaphragm

The more stimulation, the greater the ventilation rate, so its very important in the removal of CO2


What is the difference between static and dynamic compliance?

Static - the compliance at a flow of zero (end of inspiration/expiration)

Dynamic - the compliance during active flow


Explain the changes is air resistance as you go down the respiratory system

To start with there is high resistance due to passages getting lower (the conducting zones)

The resistance slowly decreases to a very low number (in the capillaries)

The number gets smaller as when the total resistance is added up, the capillaries total resistance has very little contribution to the overall resistance in the system