Lecture 3 - Control Of Breathing Flashcards
What nerve is active during exercise?
Phrenic nerve
What are muscles are active inspiration?
External intercostal muscles
How many litres are in normal ventilation?
5litres per minute
What is the maximum voluntary ventilation (MVV)?
125-175 litres per minute
What is the fold increase from normal to MVV?
30 fold increase
What is a key organ in homeostasis?
Lung
What is the Normal range for arterial pH, PO2, PCO2?
Ph = 7.35-7.45, PO2 = 81-100mmHg, PCO2 = 35-45mmHg
What happens to the blood gases during ventilation?
They are still the same
What does it mean if you have disregulated blood gases?
There is a problem with acid-base balance which is life threatening
What is the barometric pressure at sea level?
700mmHg
When is diffusion of gas more efficient?
If it has a Thin membrane or if it is saturated
What is the % of partial pressure of the inspired air?
5-6%
What are chemoreceptors used for in breathing?
Chemical control of breathing
What are peripheral chemoreceptors used for?
A back up to central chemoreceptors to control breathing
What happens if you get dsyregulation of CO2 in the blood?
You get acid base changes
What type of system is the overall respiratory control system?
Negative feedback system
What are the central controllers in the respiratory system?
Pons, medulla and other parts of the brain
What are the effectors in the respiratory control system?
Respiratory muscles
What are the sensors in the respiratory control system?
Chemoreceptors, lungs and other receptors
Where is the rhythmic cycle of breathing derived from?
The medulla oblongata
What are DRG? And what do they do?
Mainly inspiratory neurones, send signals to the diaphragm and intercostal muscles
What nerves bring input from the lungs to the DRG?
Vagus and glasophayrngeal nerves
What do the VRG contain?
Contains both inspiratory and expiratory neurones
What is the rhythmic rhythms generator modified by?
Sensory inputs
Where does the VRG send its impulses?
Larynx, pharynx, diaphragm and external intercostal muscles
What centres are found in the PONs?
Pneumoatix and apneustic centre
Where are central chemoreceptors found?
On the medulla oblongata on the brain stem
What can not readily cross the BBB?
H+ and HCO3-
What does CSF stand for?
Cerebro spinal fluid
What can diffuse through the BBB?
CO2
What is in the CSF?
Central chemoreceptors
What is the normal CSF ph?
7.32
When is CSF formed?
As plasma is filtered from the blood through the epithelial cells
What is the main important factor for central chemoreceptors?
CO2
How are central chemoreceptors altered?
By change in temperature - cool the brain stem
What does cooling the brain stem lead to?
Decrease in central chemoreceptors
What happens if you increase bicarbonate?
Causes pH to change
What happens if you decrease bicarbonate?
Causes CO2 to change
What are Peripheral chemoreceptors found?
In carotid bodies (Carotid sinus) and aortic bodies (aortic arch)
Why are peripheral chemoreceptors placed next to an artery?
Placed for surveillance for blood gases
When do peripheral chemoreceptors respond?
To low levels of arterial oxygen
When do peripheral chemoreceptors start to kick in?
Below 10% of oxygen in the air
Why do Type 2 cells have stem like properties?
So they can replicate
