Control Of Lung Function Flashcards
What nuclei are important to the generation control of the intrinsic rate and rhythm of breathing in the medulla
Dorsal respiratory group - posterior brainstem, inspiratory centre, main controller of inspiration, sets rate
Works synergistically or antagonistically with
ventral respiratory group - expiratory centre, inactive during quiet breathing, inhibits apneustic centre
What nuclei are important to the generation control of the intrinsic rate and rhythm of breathing in the pons
Apneustic centre - stimulates activity in DRG, inhibited by pulmonary afferents
Pneumotaxic centre - inspiratory off switch, regulates depth and frequency
What does D I V E stand for
Dorsal inspire ventral expire
How does the changing frequency of APs control quiet breathing
Frequency keeps increasing (ramping system) until it activates the pneumotaxic centre, causes a cessation of the rhythm, inspiration ceases to occur. After period of latency, apneustic centre helps to programme that rhythm into the DRG
What cervical vertebra does the phrenic nerve arise from, and what does it innervate
C3, C4, C5, main nerve fibre that goes into the diaphragm
What do the external and internal intercostal muscles do
External inspiration Internal exhalation (forceful)
What is the blood brain barrier and what is its purpose
Continuous capillaries with tight junctions; nerve cells are able to help more tightly pack capillary endothelial cells to prevent unnecessary leakage from cell, heavy restriction of what can come out of the blood into the CSF
How does chemosensitivity in the medulla affect breathing
Dissolved CO2 crosses BBB as it is highly lipid soluble (H+ and HCO3- can’t cross)
Creates carbonic acid, dissociates
Generated protons interact with afferent fibres in medulla
Takes signal straight to DRG to determine rate and rhythm
What do irritant receptors do
Detect foreign matter, creates short reflex that leads to coughing
Closure of glottis, forceful expiration, suddenglottsl opening, high velocity expulsion of air
What do pulmonary stretch receptors do
Activated by excessive inflation, afferent signals to respiratory centres inhibit DRG and Aneuristic centre, stimulate pneumotaxic and VRG
Inspiration inhibited, Exhalation stimulated
What do j receptors do
Sensitive to oedema and pulmonary capillary engorgement (high pressure in pulmonary circulation)
Impedes ventilation and gas exchange (increased thickness), so breathing frequency increased
If there is a ventilatory disturbance that causes a change in pH, how is this corrected
Changes in HCO3- and H+ retention/secretion in the kidneys stimulates a slow compensatory response
If there is a metabolic disturbance that causes a change in pH, how is this corrected
Change in ventilation to stimulate a rapid response the change CO2 elimination and alter pH
Where are peripheral chemoreceptors located
carotid bodies in carotid arteries, aortic bodies in aortic arch
How is breathing changed during exercise
Efferent from primary motor cortex to gross skeletal musculature partly innervate medulla, proprioceptive afferents from muscle spindles and golgi tendon organs innervate medulla on way to the brain
Causes change in breathing before exercise
