Neural + Chemical Control Of Respiration FINISH Flashcards
What are the primary respiratory muscles?
What are their nerves?
Where do these neurones arise?
- Diaphragm: phrenic nerve
- Intercostal muscles: intercostal nerve
- Pons + medulla
What are the group of neurones involved in respiration?
What do they control?
- ventral respiratory group: expiration
- dorsal respiratory group: inspiration
- pontine respiratory group: rate + pattern on breathing
What sets the basic rhythm of respiration?
The dorsal respiratory group neurones send inspiratory neuron AP to spinal nerves > diaphragm + external intercostal muscles
What does the pontine respiratory group split into?
Pneumotaxic centre
Apneustic centre
Outline the pneumotaxic centre of the pontine respiratory group
- limits inspiration > provides inspiratory off switch
- limits AP in phrenic nerve > decreases tidal volume + regulates respiratory rate
Outline the apneustic centre of the pontine respiratory group
- promotes inhalation by constant stimulation of neurones in medulla oblongata
- sends signals to delay inspiratory off switch (pneumotaxic centre)
- controls intensity of breathing
What is the apneustic centre inhibited by?
Pulmonary stretch receptors
Pneumotaxic centre IOS
Outline the voluntary control of breathing
- controlled by motor cortex in cerebrum
- inputs from limbic system + hypothalamus
- signals sent to spinal cord > respiratory muscles
Where are peripheral chemoreceptors located?
What nerves sends their info?
- located in carotid bodies + aortic bodies
- aortic bodies: send info to medulla through vagus nerve X
- carotid bodies: send info through glossopharyngeal nerve IX
Role of peripheral chemoreceptors
hypoxemia monitors
(Detect low levels of O2)
What are glomus cells derived from?
Ectoderm
Carotid body glossy cells p14
- sense pO2 <8kPa
- stimulates neurotransmitter + ATP release > act
Where are central chemoreceptors located?
On brain side of blood brain barrier
In medulla oblongata
Role of central chemoreceptors
Detect changes in pCO2
What happens when CO2 diffuses across blood brain barrier?
How do we reverse this effect?
- CO2 diffuses across blood brain barrier into CSF
- CO2 + H2O > carbonic acid > lowers pH
. - HCO3- doesn’t diffuse freely across BBB
- choroid plexus increases active transport of HCO3 into CSF
- buffer effect > increases pH
What does hypoventilation cause?
- removal of CO2 from lungs is less rapid than its production
- dissolving CO2 increases more than HCO3- > lowers pH
- causes respiratory acidosis
What happens if hypoventilation persists?
- respiratory acidosis
- kidneys respond to low pH > decreases HCO3- excretion > increases plasma [HCO3-]
- pH near to normal: partially compensated respiratory acidosis
- pH is totally normal: fully compensated respiratory acidosis
What does hyperventilation occurs?
- removal of CO2 from alveoli is more rapid than its production > CO2 falls > plasma pH rises
- causes respiratory akalosis
What happens if hyperventilation persists?
- respiratory alkalosis
- kidneys excrete more HCO3- > pH restored
- pH near to normal: partially compensated respiratory alkalosis
- pH is totally normal: fully compensated respiratory alkalosis
What do the ventral respiratory group of neurones control?
Expiration
vEntral - Expiration
What do the dorsal respiratory group of neurones control?
Inspiration
What do the pontine respiratory group of neurones control?
Rate + pattern of breathing
What nerve sends signals from aortic bodies?
Vagus nerve X
What nerve sends signals from carotid bodies?
Glossopharyngeal nerve IX
