Respiratory system - Acid base balance adn central control Flashcards
What is the rhythm and depth of our breathing set by?
the central pattern generator (CPG) = Pacemaker neurones in the medulla oblongata
What is the central pattern generator?
A network of communicating pathways which work to produce an appropriate respiratory rate and depth based on neeed
What innervates muscles of inspiration
neurones of the dorsal respiratory group which stimulate motor neurones innovating muscles of inspiration: diaphragm and external intercostal
What stops us breathing in?
Hering-Breuer Reflex: Stretch receptors in our lung and thoracic cage = turns off stimulation of dorsal respiratory group = inspiration muscles stop contracting and recoil occurs
When fully expanded what happens
Hering breuer reflex means that the rate of impulses increases so lungs stop expanding.
During active expiration what neurones involved?
Neruones in the ventral respiratory group send impulses to expiratory muscles (Internal intercostal muscles and abdominal muscles)
Where in the brain is the medulla oblongata?
Last part of brain stem before spinal cord- where respiratory centre is
What two parts of the brain control respiration
Receptors that send impulses for Hering Breuer reflex send to pons (switch off dorsal resp group) = just infront of MO = two communicate to control repsiration
What si the role of pulmonary stretch receptors
make u stop breathing before you burst!
Where does conscious of breathing come from?
Cortex of brain = to change breathing pattern = deep, slowly etc
If breath in irritant what happens
Irritant receptors detect = causes you to hold breath = reduce depth of breathing = so won’t go into lungs
Where are the locations of peripheral chemoreceptors.
What do they monitor
What is their innovation
- Carotid and aortic arteries (same as baro that measure BP) = not same!
- Called carotid and aortic bodies, monitor PaO2, PaCO2 (most important) and arterial [H+] IN ARTERIOL BLOOD!
- High blood supply
- Innovated C = cranial nerve 9. A = cranial nerve 10
What does the conc of H+ ions tell us about respiration function?
Indicated CO2 conc. CO2 is carried by carbonate = has a H+
Also indicates if there is a problem elsewhere!
What to remember about aortic bodies
More important in foetus, not v active in adult
Carotid bodies detecting changes, more sensitive in CO2 or O2 changes?
- CO2 changes
- Because of the oxygen dissociation curve: Oxygen level has to drop quite a lot before Hb starts to become desaturated. Carotid bodies don’t detect until ppO2 dropped to about 70% = serious loss of resp function before carotid bodies activated!
