Respiratory: Physiology - Control of Respiration - Lecture 1 Flashcards
What are the two ways Respiration is controlled?
Neural Control
Chemical Control
What does the Neural Control control?
Sets up the rhythm of respiration
Inspiration followed by expiration
What are the parts of the brain stem?
Superior to Inferior:
Midbrain
Pons
Medulla Oblongata
Spinal Cord
What occurs to ventilation if the brainstem is sectioned above the Medulla?
Ventilation still retained
What occurs to ventilation if the brainstem is sectioned below the Medulla?
Ventilation ceases
What part of the brainstem is the rhythm generator of respiration?
The Medulla
- Network of Neurons called the Pre-Botzinger Complex
Where is the Pre-botzinger complex located?
Located near the upper end of the medullary respiratory centre
What part of the Brainstem gives rise to inspiration?
Dorsal Respiratory group neurones (Inspiratory)
- Located in the Medulla of the brainstem
Explain the innervation of the Dorsal respiratory nerves?
Fire in bursts
Firing leads to contraction of inspiratory muscle
Stop firing to allow for passive expiration
What nerve bring about active expiration during hyperventilation?
Vental Respiratory group neurones
What do the Ventral Respiratory group excite?
Excite Internal Inercostals
Abdominal
This causes forceful expiration
What group of nerves can modify the rhythm of respiration?
Pneumotaxic centre
Located in the Pons
What does stimulation of the Pneumotaxic centre cause?
Termination of Inspiration
When is the Pneumotaxic centre stimulated?
When the dorsal respiratory neurones fire
What occurs if the Pneumotaxic centre does not fire?
Breathing is proglonged
Inspiratory gasps (This is called Apneusis respiration)
What is the apneustic centre?
The Apneustic centre excites the inspiratory area of the medulla
It is use for Prolonged Inspiration
What part of the brainstem generates the rhythm of breathing?
Medulla
What part of the brainstem modifies the rhtyhm of breathing?
Pons
What are the involuntary modifcations of breathing?
Pulmonary stretch receptor Hering-Breuer relfex
Joints receptors reflex in exercise
Stimulation of respiratory centre by temperature adrenaline or impulses from cerebral cortex
Cough reflex.
When do pulmonary stretch receptors active?
Inspiration
Only activated at large or greater than 1 litre tidal volumes
- Prevent over inflation of lung during hard exercise
What is the Hering-breuer reflex?
Pulmonary stretch receptors activating during inspiration.
Afferent discharge inhibits inspiration
How do Joint receptors affect breathing?
Impulses from moving limbs reflex increase breathing
Probably contribute to increased ventilation during exercise
What factors may increase during ventilation during exercise?
Body Movement Adrenaline Impulses from the cerebral cortex Temperature Accumulation of CO2 H+ generated by active muscles
Describe how the cough reflex happens?
Short intake of breath, followed by closure of the larynx, then contraction of abdominal muscles (increases intra-alveolar pressure), and finally opening of the larynx and expulsion of air at a high speed
