BIO210Y5 Lecture Notes - Lecture 27: Medulla Oblongata, Hypercapnia, Bronchiole
Document Summary
Stretch receptors located in the smooth muscle around the bronchioles are stimulated for lung expansion. The respiratory muscles are inhibited by the respiratory rhythmicity center, and inhalation stops. The ventral and dorsal respiratory groups are in medulla oblongata. The expiratory centers of the vrg (ventral respiratory group) are then stimulated and forced exhalation begins. Vrg pacemaker cells in medulla oblongata. Stretch receptors located in the alveolar walls are stimulated as the elastic fibers recoil and the alveolar volume is reduced. The receptors basically tell that the volume has increased so we need to reduce the volume. The expiratory centers of the vrg are inhibited. Forced inhalation now begins, with activation of drg (dorsal respiratory group) and the inspiratory centers of vrg. Inspiratory centers of drg (18 b) - case study. Hypercapnia (increasing trend in co2 levels ) Resulting in decreasing ph and o2 levels. Utilize a negative feedback loop to attain homeostasis.
