Lecture 10: Control Of Ventilation Flashcards
Where does rythmogenesis occur?
In the medulla
Where is respiration halted?
The section between the medulla and spinal cord
Which 2 centres are involved in rythmogenesis?
Dorsal and Ventral respiratory groups
What does the DRG do?
- Receives afterrent input
- has respiratory cells that drive the phrenic nerve
- contains cells that are active during inspiration
- corresponds to the nucleus tractus solitarius (NTS)
What does the VRG do?
- has outputs to accessory organs
- houses the expiratory motor neurons
- controls the upper airway and vagas stimulation to the ASM via the Nucleus Ambiguus
- has cells active during expo and som in inspo
What is the on switch theory?
There are cells that are constant driving the diaphragm to contract but they are connected through interneurons to inhibitory cells that stop the driving
The kernel model depends on ______________________________________________________
Pacemaker activity in single neurons
Where is the pre-botzinger complex and what does it do?
Just above the VRG and it houses the pacemaker cells
Pacemakers in the pre-botzinger complex use _____________ as their neurotransmitter and all _________________________
Glutamate
Depolarise in phase
What is apneusis?
Prolonged inspo with short expo
Where is the pneumotaxic area and what is its function?
Found in the pons and shortens inspo
The pneumotaxic area and vagal afferents modify breathing by modifying the _______________ and ____________
Inspiratory ramp and expiration
Where does the phrenic nerve arise from and what does it innervate?
C2-C5 innervates the diaphragm
The Nucleus Ambiguus drives the ________________ to the __________ and the _________________ to the _____________
Vagal afferents to the bronchi
Glossopharyngeal nerve to larynx
The Nucleus Retroambigualis drives nerves to the _________________ and _________________.
Intercostals and abdominal muscles
Define Apnoea:
No breathing resulting from damage to the medulla
Define hyperpnea:
Increases breathing
Define hypopnea:
Reduced breathing
Define hyperventilation:
Metabolically inappropriate increased ventilation
Define apneusis:
Prolonged inspo
Define gasping:
Prolonged expiration
Describe the central chemoreceptors:
Found on the ventral surface surface of the medulla and are bathed in CSF. They respond to changes in pH, some cells are activated by acid and some are inhibited
Describe peripheral chemoreceptors:
Found in the carotid and aortic bodies. Carotid body responds to CO2, H+ and O2. Aortic body responds to CO2 and O2. Glomus cells are the detector cells.
Describe glomus cells:
- Detect pH, O2 and CO2
- neuronal in origin and show AP and release neurotransmitters
How do glomus cells detect pH?
Detect intracellular pH by protonation of Kca channels which results in a decreases K efflux –> hypopolarised –> AP
CO2 and arterial pH change internal pH
How is O2 detected?
Requires an O2 sensitive enzyme, haemoxigenase, which is normally bound to O2. If Hb saturation decreases so will haemoxigenase which causes CO production which opens K channels –> keeps cells polarised .’. Not releasing neurotransmitter
What happens when O2 < 60mmHg?
Large increase in ventilation
Ventilation at a given PaO2 is enhanced by ____________
Increased PaCO2
