1. RESPIRATORY PHYSIOLOGY
RESPIRATORY SYSTEM - 2
RESPIRATORY PHYSIOLOGY

2. Brain Stem Respiratory Centers
SEQUENCE:
Voluntary (cerebral cortex) or involuntary (Pons and medulla)
Pons (apneustic and pneumotaxic)
Medulla (rhythmicity ctrs)
Pre-Botzinger
Inspiratory
Expiratory
Exercise related
Motor neurons in dorsal/ventral
respiratory group
Activate/inh spinal nerves
Diaphragm contracts

3. Sensory Input From Aortic and Carotid Bodies
Central chemoreceptors: in medulla oblongata
Peripheral chemoreceptors: in aortic and carotid bodies
Sense carbon dioxide levels
Send sensory information to medulla oblongata

4. Regulation of Ventilation by the CNS

5. Effects of PCO2 on Ventilation
Hypercapnia = high CO2
Hypocapnia = low CO2

6. Chemoreceptors in the Medulla
Central chemoreceptors respond to CO2, but not in the blood

7. Regulation of Breathing in Response to CO2 Levels

8. Comparing the effects of blood CO2 and O2 on breathing
Hypoxic drive
p. 558

10. Pulmonary Receptors can also have an effect on ventilation.
1) Unmyelinated C fibers are sensory neurons that are stimulated by capsaicin, which produces temporary apnea (cessation of breathing), followed by rapid, shallow breathing.
2) Irritant Receptors (rapidly adapting receptors) in the wall of the larynx, cause a person to cough (due to smoke, particulate matter), and an increase in pulmonary interstitial fluid.
3) Hering-Breuer reflex is stimulated by pulmonary stretch receptors.
- important in maintaining normal ventilation in the newborn
- may contribute to respiratory control at high tidal volumes, such as during exercise