Control Of Gas Exhange Flashcards
What lung receptors are important in the reflex modification of breathing ?
- Stretch receptors
- Juxta-pulmonary “J” receptors
- Irritant receptors
- Proprioceptors
What do stretch receptors do ?
They cause shorter, shallower breaths.
They are sensitive to mechanical deformation.
What do J receptors do ?
They are sensitive to changes in the pulmonary circulation
Located in alveoli walls
What do irritant receptors do ?
Respond to the presence of irritants in the airways, causing coughing
Located throughout the airways
What do proprioceptors do ?
Detect changes in the movement of the rib cage
How do we measure metabolism through ventilation?
- CO2 production from Pco2
- O2 consumption from Po2
- H+ production from PH
What are changes in blood chemistry detected by ?
- Central chemoreceptors
- Peripheral chemoreceptors
Where are central chemoreceptors located?
The brainstem, near ventolateral surface of medulla.
What do central chemoreceptors do ?
They are sensitive to PH of cerebral spinal fluid (CSF).
They send signals to the medullary respiratory centre to increase ventilation.
They have a relatively slow response time.
Where are peripheral chemoreceptors found ?
Carotid and aortic bodies (high blood flow areas)
What do peripheral chemoreceptors do ?
They detect a decrease in oxygen or an increase in CO2, so they increase their firing rate to adjust ventilation.
They respond rapidly
What is the ventilatory response to increased CO2 ?
Increased minute ventilation
(And tidal volume and breathing frequency)
Responses to hypoxia and hypercapnia
The body is much more sensitive to an increase in the partial pressure in carbon dioxide than a decrease in the PP of oxygen.
So a rise in PP of CO2 is the brain drive to breathe
What are characteristics of the diving reflex in mammals ?
- Reduced heart rate
- Increases peripheral vasoconstriction
- Lactate accumulation in muscle
- Energy conservation
