Control of Breathing Flashcards
Why do we need to control breathing?
To match alveolar ventilation with metabolic demand
Keep arterial PO2 and PCO2 very stable
What part of the brain controls breathing?
Medulla and pons in brainstem
What are the 3 control centres?
Medullary respiratory centre
Apneustic centre
Pneuomtaxic centre
What 2 things override the control of breathing?
Voluntary control or swallowing
Involuntary reflexes eg sneezing
What are the 3 main groups of neurons`in medullary respiratory centre?
Dorsal respiratory group (DRG)
Ventral respiratory group (VRG)
Pre-Botzinger complex - upper part of VRG
What is the medullary respiratory centre?
Reticular formation of medulla where respiratory pattern is generated
What is the MoA of the DRG?
Afferent signals of glossopharyngeal and vagus via spinal motor neurons activate inspiratory muscles
What does activation of neurons in DRG during quiet breathing cause?
Repetitive bursts of APs to respiratory muscles
What cells are present in the VRG?
Expiration cells
What leads to the activation of expiration cells?
Forceful expiration during excercise
What is the role of pre-botzinger complex?
Respiratory rhythm generator
What nerves innervates the diaphragm?
Phrenic nerve
What pattern does inspiratory muscle activity take?
Ramp like pattern
Why is expiration passive?
Due to elastic recoil of lungs
Where is the apneustic centre located?
Lower pons
What is the role of the apneustic centre?
Impulses lead to an excitatory effect on inspiratory area of medulla -> prolong ramp action of APs
Where is the pneumotaxic centre located?
Upper pons
What are the 4 roles of the pneumotaxic centre?
Inhibits inspiration
Modulates apneustic centre
Regulates inspiratory volume and rate
Fine tuning
What do peripheral chemoreceptors mainly sense?
Oxygen
What do central chemoreceptors mainly sense?
CO2 sesning
