Control Of Ventilation Flashcards
What’s reflexes are included as into the cycle of breathing
Chemoreceptors
- arterial and central
Lungs
Airways
Cardio system
Muscles/joints
Skin
What is response for setting the basic unconscious rhythm of breathing?
The central pattern generator in the medulla
- takes readings from the chemoreceptors and sensory input from cranial nerves to generate breathing in respiratory muscles
What does the peripheral chemoreceptors do?
Found in CN 10 and 9
Take readings from Partial pressures of CO2/o2 and pH. Uses thes readings to relay information back to the central pattern generator and allows it to either speed up or slow down breathing
note the central chemoreceptors in the brain also function to regulate the pattern generator, however they are only sensitive to CO2 and pH
Vagal and phrenic effects on lung inhalation/exhalation (Hering-Breuer reflex)
Phrenic nerve is stimulated to contract diaphragm and allow lungs to inflate.
Before lungs reach max inflation, pulmonary stretch receptors are activated and use vagus nerve to send signals to the medulla inspiratory area. This turns off the inspiratory center and turns the phrenic nerve activity
- prevents the lungs from being overinflated naturally
Where is the central hub for breathing located in the human body?
Medulla
- primarily DRG and nucleus tractus solitarius
DRG
Dorsal respiratory group of neurons that control inspiration only with control of the phrenic nerve
What is the pons affect one breathing?
Modulates breathing but is not essential for breathing
- no pons causes extended inspiration since it contains the apneustic center
Apneustic center vs pneumotaxic center
Apneustic:
- promotes inspiration
Pneumotaxic:
- inhibts inspiration
Both are found in the pons
Difference between DRG and VRG
DRG:
- contains only inspiratory neruons
VRG:
- contains both inspiratory and Expiratory neurons
What is the most important chemical associated with establishing ventilation?
Partial pressure of CO2
There is a direct relationship between PCO2 and ventilation rates
What happens to the ventilation centers when hypoxia is introduced?
Resting alveolar ventilation is naturally increased
Also, the ventilation rate is even more sensitive/ increases the relationship even more to PCO2 levels
What do peripheral chemoreceptors respond to?
Carotid And aortic bodies
Hypoxia, hypercapnia and metabolic/respiratory acidosis
The glomus cell
The chemo sensor cell inside the peripheral chemoreceptors
In response to hypoxia, hypercapnia and acidosis:
- inhibits K+ channels
- raises intracellular calcium
- releases neurotransmitters
General step by step response in glomus cells
1) oxygen goes down
2) CO2 goes up and pH goes down
3) activates H+ channels and inhibits sodium channels
4) inhibits potassium channels
5) increases intracellular calcium
6) releases neurotransmitters to the glossopharyngeal nerve
Central chemoreceptors
Take inputs from cerebral spinal fluid and secondary responses from peripheral chemoreceptors
- DOESNT contact the blood so doesn’t directly read blood
- really only directly pays attention to CO2 since it is the only molecule in blood that can pass the BBB