Control of lung function (33) Flashcards
What are the 3 major respiratory groups of neurons in the respiratory centre?
- in medulla: dorsal respiratory group and ventral respiratory group
- in pons, pontine respiratory group has two area: pneumotaxic centre and apneustic centre
What is DIVE a mnemonic to remember?
Dorsal Inspire Ventral Expire
What is the role of the dorsal respiratory group?
- initiates inspiration
- sets and maintains rate of respiration
- integrating centre that gives output to VRG
What is the role of the ventral respiratory group?
- expiratory centre
- inactive during quiet, restful breathing
- sends inhibitory impulses to apneustic centre
What is the role of the apneustic centre?
- stimulates activity in DRG
- inhibited by pulmonary stretch receptors
- inhibits pneumotaxic centre
What is the role of the pneumotaxic centre?
- controls both the rate and the pattern of breathing
- antagonist to apneustic centre, which produces abnormal breathing during inhalation
- limits inspiration, providing ‘inspiratory off-switch’
Which nerve drives breathing?
phrenic nerve- innervates diaphragm
What cells help keep tight junctions in place in the blood-brain barrier?
glial cells
How do the central chemoreceptors in the medulla sense changes in H+?
- H+ cannot dissolve across the endothelial cells, as they are charged
- CO2 can move through (v. lipid soluble)–> combines w/ water to form H+ and bicarbonate in CSF
- chemoreceptors detect H+ in ventral surface of medulla
N.B. CO2 reflects metabolism
What are irritant receptors?
- in airways
- afferent receptors within epithelium that detect irritants e.g. particulates, water
- leads to cough–> glottal closure and contraction of respiratory muscles then glottal opening and rapid expulsion of air
What are stretch receptors?
- in airway smooth muscle
- detect excessive inflation (Hering–Breuer inspiratory-inhibitory reflex to prevent hyperinflation of lungs)
- inspiration inhibited and expiration stimulated
What are J receptors/pulmonary C-fiber receptors?
- next to capillaries of alveoli
- detect accumulation of fluid or identify pulmonary capillary engorgement
- -> increases breathing frequency bc these ^ cause a decrease in oxygenation
What is alkalaemia?
refers to higher than normal pH of blood
What is acidaemia?
refers to lower than normal pH of blood
snapshot in time
What is alkalosis?
circumstances that will decrease [H+] and increase pH
and create alkalaemia