Respiration 4 Flashcards
What are the 2 categories of lung disease?
Obstructive
Restrictive
What is an obstructive lung disease?
Reduction in flow through airways
What is a restrictive lung disease?
Reduction in lung expansion
What is the overall effect of lung disease?
A reduction in ventilation in the lungs
Name 3 causes of obstructive lung disease
Excess secretions
Bronchoconstriction
Inflammation
Why does narrowing of the airways lead to reduced flow?
Narrowing of the airways leads to increased resistance which leads to a decreased flow rate
Describe the difference between a normal V/T graph and an obstructive lung disease V/T.
The FEV1 in an obstructive will be < 80% of FVC in obstructive lung disease
Describe the difference between normal volume time curves and obstructive disease volume time curves
In obstructive disease, forced vital capacity is unchanged but there is a decrease in FEV1.
The point volume is the same but takes longer to get there.
Describe the difference in shape in flow-volume loops in normal vs obstructive.
Initial and peak flow are similar
There is a sharp fall in flow-rate on obstructive - leads to a concave shape graph.
What disease produces a persistent productive cough and excess mucus secretion?
Chronic bronchitis
What disease causes hyperactive airways ?
Asthma
What disease causes structural changes?
Chronic obstructive pulmonary disease
What other diseases is COPD linked to?
Bronchitis and emphysema
Which disease is associated with a loss of elastin?
Emphysema
What is an atopic trigger?
An extrinsic trigger e.g. allergies
What is a non-atopic trigger?
An intrinsic trigger e.g. respiratory infections
Explain the asthma response
A non atopic or atopic trigger causes the asthma response.
Inflammatory cells move across the blood into the airways ->
Release of inflammatory mediators (histamine) ->
Smooth muscle has histamine receptors which trigger bronchoconstriction ->
Reduces airflow
What is salbutamol ? What is its effect?
A short acting B2 adrenoreceptor used for short term treatment of asthma.
Dilation of the airways by inhibiting contraction
Is salbutamol an agonist or antagonist?
Agonist, stimulates the airways
What is a long acting asthma treatment?
Glucocorticoids e.g. beclomethasone
What is the mechanism of glucocorticoids?
Interact with beta2 adrenoreceptors ->
Activates coupling of g proteins with adenylcyclase ->
Enhances production of cAMP which activates protein kinase A causing smooth muscle contraction
Name 2 effects of restrictive lung disease
Reduced chest expansion
Loss of compliance (fibrosis)
Describe a restrictive lung disease spirometer
Vital capacity is reduced compared to the predicted value
Describe a restrictive disease volume time curve.
The curve is depressed
FEV1 is reduced
Reduction in vital capacity
Describe a restrictive disease flow volume loop
Normal shape with a decrease in volumes of air moved
Reduction in peak flow
Explain how inhaling asbestos leads to lung disease
Asbestos is foreign to the body so macrophages are sent to break down the asbestos ->
The body is unable to break it down, leading to a build up of fibrous tissue around the asbestos ->
This leads to a loss of compliance
Where is the basic respiratory rhythm generated?
Centres in the medulla
What would a lesion between the medulla and pons lead to?
A maintenance in the basic breathing pattern which could be overridden.
Which type of respiration does the dorsal axis in the medulla link to?
Quiet expiration
Which type of respiration does the ventral axis link to?
Forced inspiration
When is the ventral respiratory group inactive?
During quiet respiration
When is the dorsal respiratory group active?
Spontaneously ->
period of activity - shut off - period of activity
Shut off period causes expiration
What is the pre botzinger complex responsible for?
Inspiration
Where is the pre botzinger complex located?
At the top of the dorsal respiratory group
How does the pons influence breathing?
The pons has 2 centres which send signals to the medulla to regulate rate and depth of breathing.
What in the pons increases the rate of breathing? What is its mechanism?
The pneumotaxic centre
Inhibitory effect on the inspiration centre so shortens inspirations
What in the pons increases the depth of breathing? What is its mechanism?
Apneustic centre
Stimulates the inspiratory system prolonging inspirations
Explain the hering breuer reflex
Stretch receptors detect the volume of lungs ->
Send signal to the inspiratory centre (medulla) via the vagus nerve ->
The medulla sends a signal via the phrenic nerve which causes the diaphragm to contract to prevent over inflation
What would occur if a rise in CO2 is detected in cerebral spinal fluid?
Central chemoreceptors in csf detect the rise which has a larger effect on pH ->
stimulation causes an increase in ventilation so pH returns to normal
Where are peripheral chemoreceptors located?
Carotid body and aortic arch
What does stimulation of peripheral chemoreceptors lead to?
Increased inspiration
