Control of lung function Flashcards
Where is breathing controlled in the brain?
Medulla oblongata.
In the medulla oblongata what is the dorsal respiratory group responsible for?
Inspiration.
In the medulla oblongata what is the ventral respiratory group responsible for?
Expiration.
What accronym can be used for respiratory groups?
DIVE. Dorsal inspire, ventral expire.
What controls the rate of the breathing?
Pneumotaxic centre.
What controls depth of breathing?
Pneumotaxic centre.
What does the apneustic centre do?
Stimulates dorsal respiratory group activity.
What switches off inspiratory activity?
Pneumotaxic centre.
What stimulates inspiration?
Apneustic centre.
What inhibits the apneustic centre?
Ventral respiratory group.
What sets the rate of breathing?
Dorsal respiratory group.
What nerve innervates the diaphragm?
Phrenic nerve.
What allows carbon dioxide to travel through blood brain barrier?
High lipid solubility. Small and uncharged.
How do nerves in the medulla detect changes in pH?
Carbon dioxide diffuses through capillary in brain into CSF. Reacts with water to produce H+ ions. H+ ions activate medulla neurones.
Where are irritant receptors in the lungs? What are they involved in?
Within upper airway epithelium. Coughing.
Coughing mechanism?
Expirating against closed glottis with sudden glottis opening resulting a high velocity expulsion of air.
What occurs when there is excessive inflation of lungs?
Pulmonary stretch receptors activated. Afferent signals to medulla result in inhibition of dorsal respiratory group and apneustic centre by activation of pneumotaxic centre and stimulation of ventral respiratory group. Inspiration inhibited and expiration stimulated.
Where are J receptors found and what do they detect?
Alveoli. Swelling.
What receptors detect pulmonary oedema and pulmonary capillary engorgement?
J receptors.
What can J receptors do if activated?
Increase breathing frequency in response to events such as pulmonary oedema which cause a decrease in oxygenation.
Why are drastic changes in pH of blood bad?
Alters 3D structure of proteins - enzymes, hormones and protein channels.
Why do small changes in concentrations of H+ ions or basic ions not affect pH of blood?
Blood has big buffering capacity .
What is pH?
Logarithmic concentration scale of H+ ions.
What is acidosis?
Circumstances that lower pH.
What is alkalosis?
Circumstances that increase pH.
What is alkalaemia?
Higher than normal pH.
What is acidaemia?
Lower than normal pH.
2 area in body that regulate pH of blood? Difference in how they act?
Lungs and kidney. Lungs can restore pH of blood much faster than kidneys.
How do lungs regulate pH?
Change ventilation rate. If blood pH is too low then ventilation rate increases to get rid of CO2.
How do kidneys regulate pH?
Changes in the amount of bicarbonate or H+ excreted.
Where are the peripheral chemoreceptors that detect changes in pH located?
Aortic arch and carotid sinus.
Where are the central chemoreceptors that detect changes in pH located?
Medulla.
What do peripheral chemoreceptors detect?
Oxygen concentration.
What are the peripheral chemoreceptors called?
Aortic and carotid bodies.
What neurones connected to muscles cause increase in breathing rate when muscles move?
Proprioceptive afferent neurones from golgi tendon organ (responds to stretch on tendon) and muscle spindle (stretch receptors) innervate medulla.
What receptors in skin affect breathing rate?
Temperature receptors.
Why is cold shock deadly?
Causes hyperventilation and so breathing can’t be controlled. Leads to drowning.
