Respiration 4 lung disease + control of respiration Flashcards
Semester 1 year 1
What are the 2 categories of lung disease?
-obstructive - reduction in flow through airway, increased resistance
-restrictive - reduction in lung expansion
What does the ratio of FEV1 to VC tell us?
Gives an idea of lung health - over 80% is normal
What is obstructive lung disease and what can it be due to?
-result of the airway narrowing
-due to: excess secretions, bronchoconstriction (asthma), inflammation
What happens to resistance , FEV1 and FVC because of obstructive lung disease?
-increased resistance to air flow
-decrease in FEV1
-in many cases, FVC is unaltered
What are examples of obstructive lung diseases?
-chronic bronchitis persistent - cough + excess mucus
-asthma - inflammatory disease
-chronic obstructive pulmonary disease (COPD) - structural changes
-emphysema - loss of elastin
What is restrictive lung disease?
-reduced chest expansion due to chest wall abnormalities + muscle contraction deficiencies
-loss of compliance (fibrosis) due to normal ageing process, collagen increase + exposure to environmental factors
What happens to VC, FVC and FEV1 because of restrictive lung disease?
-decrease in VC
-decrease in FVC
-FEV1 % can remain unaltered or increase
What is asbestosis?
Slow build up of fibrous tissue leading to loss of compliance
What can trigger asthma?
-atopic (extrinsic) - allergies, contact with inhaled allergens
-non atopic (intrinsic) - respiratory infections, cold air, stress, exercise, inhaled irritants, drugs
What is the bodily response to asthma?
-movement of inflammatory cells into the airways
-release if inflammatory mediators
What is a short acting treatment for asthma?
Short acting beta 2 adrenoreceptor agonists - cause dilation of airways
What are long acting treatments for asthma?
-inhaled steroids - glucocorticoids act to reduce inflammatory response
-long acting beta 2 adrenoreceptor agonists
What generates the basic respiratory rhythm?
Centres in the medulla
What are the 2 groups of neurons in the medulla?
-dorsal respiratory group
-ventral respiratory group
What does the PreBotC complex do?
Generates a basic rhythmic pattern for breathing
What do the dorsal respiratory neurons do?
Controls quiet inspiration
What do the ventral respiratory neurons do?
They’re responsible for inspiration + expiration under forced conditions
Where is the dorsal respiratory group and what does it do?
-in the medulla
-controls inspiration by sending signals to the inspiratory muscles
When is the dorsal respiratory group active?
Spontaneously active
What is the ventral respiratory group and when is it active?
-controls inspiration + expiration
-inactive during quiet respiration
-during activation, helps control forceful inspiration + expiration
What do the Pons do?
2 centres send stimuli to medulla to regulate rate + depth of breathing
What are the 2 centres in the Pons and what do they do?
-pneumotaxic centre - increase rate by shortening inspirations (inhibitory effect on inspiratory centre)
-apneustic centre - increase depth + reduce rate by prolonging inspirations (stimulates inspiratory centre)
What do stretch receptors do?
-Hering Breuer reflex
-stretch receptors in the lung sends signals back to medulla to limit inspiration + prevent over-inflation of lungs
What do central chemoreceptors do?
-monitor conditions in cerebre-spinal fluid
-sense CO2 + pH
-indirect response to a rise in CO2 - stimulation leads to increased ventilation
What do peripheral chemoreceptors do?
-respond to increased CO2, decreased pH + decreased O2
-stimulation leads to increased ventilation
Where are peripheral chemoreceptors located?
In carotid body + aortic arch
