Respiratory: Control of Respiration Flashcards
Where is the major rhythm generatory for resp
Medulla
What network of neurones generate the breathing rhythm?
Pre-botzinger complex
Where is this complex located
the upper end of the medulla
What gives rise to inspiration
Dorsal respiratory group of neurones fire.
Leads to contraction of inspiratory muscle= INSPIRATION
When firing stops= passive expiration
What gives rise to active expiration
Increased firing of dorsal neurones excites a second group of ventral neurones which excite internal intercostal muscles and illicit forceful expiration
How can the rhythm be modified?
By neurones in the pons
Explain the mechanism of modifying rhythm in the pons pneumotaxic centre
The pneumotaxic centre is stimulated when dorsal respiratory neurones fire.
Stimulation terminates inspiration.
What would happen without the pneumotaxic centre
breathing would be prolonged inspiratory gasps with brief expiration known as APEUNSIS
Explain the rhtym modifyin by the apneustic centre
impulses from theses neurones excite inspiratory area of medulla and prolong inspiration
Name examples of involuntary modifications of breathing
Pulmonary stretch receptors refelx
Joint receptors reflex
Stimulation of resp centre by temp, adrenalin or impulses from cerebral cortex
cough reflex
Explain pulmonary stretch receptors
Activated during inspiration- inhibits inspiration
Only fire at large tidal volumes
Describe the joint receptor reflex
Impulses from moving limbs reflexly increased breathing
What factors may increase ventilation during exercise
Body movement Adrenaline Impulses from cerebral cortex Increased body temp Accumulation fo COs and H plus ions
Explain the cough reflex
Activated by irritation of the airways or tight airways eg asthma
Afferent discharge stimulates short intake of breath followed by closure of the larynx, the contraction of abdominal muscles and opening of the larynx and there is an expulsion of air at high speed
Where is the cough reflex controlled
the medulla
