Neural control of breathing Flashcards
Why is ventilation regulated?
Regulated to meet varying O2 demand/CO2 production
What is breathing initiated by and what do they provide?
Breathing is initiated by neural activation of respiratory muscles, which provide the movement required for ventilation
What do resp muscles consist of and what do they require to contract?
As Resp muscles consist of skeletal muscle, they require neural inputs/stimulation to contract
What provides the contractile signal?
Innervation from motor neurons synapsing from descending spinal tracts provide the contractile signal
Muscles utilized in quiet breathing during inspiration
Diaphragm
Muscles utilized in quiet breathing during expiration
Elastic recoil
Which respiratory muscles are utilized in increased/forced ventilation during inspiration?
External intercostals
Which respiratory muscles are utilized in increased/forced ventilation during expiration?
Elastic recoil
Internal intercostal
Which accessory muscles are utilized in increased/forced ventilation during inspiration?
Pectorals
Sterno-mastoid
Scalene
Which accessory muscles are utilized in increased/forced ventilation during expiration?
Abdominal
What is the basic breathing pattern generated by?
Generated by neuronal systems within the brainstem
How does the central pattern generator determine how often and hard to breathe?
Higher brain centers-Cerebral cortex(voluntary control over breathing) Other receptors-Emotional stimuli acting through the hypothalamus Respiratory centers-Medulla and pons Peripheral chemoreceptors Stretch receptors in lungs Central chemoreceptors Receptors in muscles and joints Irritant receptors
What does the CPG integrate?
The CPG integrates data from various neuronal inputs to regulate ventilation
What do central chemoreceptors respond to?
Central chemoreceptors respond indirectly to changes in arterial PCO2
What monitor changes in arterial CO2?
Central respiratory chemoreceptors present in medulla indirectly monitor changes in arterial CO2
What does CRC respond to and why and what do they not directly respond to?
Although CRC respond to changes in [H+] within cerebrospinal fluid, as H+ doesn’t cross the blood brain barrier, CRC do not directly respond to changes in blood pH
What do peripheral chemoreceptors respond to?
Peripheral chemorecceptors respond to changes in arterial O2, CO2 and pH
What are carotid and aortic bodies activated by?
Activated by a decrease in PaO2, increase in PaCO2 and acidaemia
What do carotid and aortic bodies signal to and what do they do?
Signal to respiratory centers in medulla via sensory nerves to increase ventilation(negative feedback)
In a hypercapnic drive, what is ventilation proportional to?
Ventilation is proportional to PaCO2
In a hypoxic drive, what happens?
Hypoxaemia(low PaCO2) stimulates increased ventilation
What is central sleep apnoea?
Temporary cessation of breathing during sleep caused by dysfunction of the processes that initiates breathing
What are central sleep apnoea negative effects?
Include:
- tiredness
- CV compoliations
What are the causes of central sleep apnoea?
- Stroke
- Drugs
- Altitude
