1. Neuronal demand

2. functionally

3. Hypothalamus cerebral cortex
rhythm medulla motor

4. Confirm 中脑

6. pons

8. time course prolonged

9. Respiratory center summary midbrain pons medulla Spinal cord
(upper pons) – inhibits inspiration
pneumotaxic center
pons
Apneustic center (lower pons) – to promote inspiration
medulla
Cause the basic respirarory rhythm
transfer for brain and respiratory muscle
Spinal cord
hypothesis of three –lever of respiratory center

10. PBKF neurons
evidence

11. dorsal respiratory group
ventral respiratory group

12. Two respiratory nuclei in medulla oblongata
Inspiratory center (dorsal respiratory group, DRG)
inspiratory neuron
more frequently they fire, more deeply you
inhale，longer duration they fire, breath is
prolonged, slow rate
Expiratory center (ventral respiratory group, VRG)
expiratory neuron, inspiratory neuron involved in forced expiration mainly

13. pond PBKF neurons Spinal cord dorsal respiratory group
ventral respiratory group
Spinal cord

14. hypothesis of basic rhythm——pacesetter cell theory
pneumotaxic center
PBKF neurons
Central inspiratory activity generator inspiratory nueron
Inspiratory off swithch
mechanism
Inspiratory muscle
motor nueron
Spontaneous motor

15. Rhythmic Ventilation (Inspiratory Off Switch)
Starting inspiration
Medullary respiratory center neurons are continuously active (spontaneous)
Center receives stimulation from receptors and brain concerned with voluntary respiratory movements and emotion
Combined input from all sources causes action potentials to stimulate respiratory muscles

16. Increasing inspiration Stopping inspiration
More and more neurons are activated
Stopping inspiration
Neurons receive input from pontine group and stretch receptors in lungs.
Inhibitory neurons activated and relaxation of respiratory muscles results in expiration.
Inspiratory off swithch.

17. 3. Higher Respiratory Centers
regulate the activity of the more primitive control centers in the medulla and pons.
Allow the rate and depth of respiration to be controlled voluntarily.
During speaking, laughing, crying, eating, defecating, coughing, and sneezing. ….

18. automatic

19. Originated mediated eliciting
deflation

20. Hering-Breuer Reflex or Pulmonary Stretch Reflex
Including pulmonary inflation reflex and pulmonary deflation reflex
Receptor: Slowly adapting stretch receptors (SARs) in bronchial airways.
Afferent: vagus nerve

22. Significance of Hering-Breuer reflex
Terminate inspiration timely.
enhance inspiration/expiration transition， increase respiratory frequency.
Normal adults. Receptors are not activated at end normal tidal volumes.
Become Important in Chronic obstructive lung diseases when lungs are more distended.
Infants. Probably help terminate normal inspiration.
Become Important during exercise when tidal volume is increased.

25. Chemoreceptor Reflex Two Kinds of Chemoreceptors
Central Chemoreceptors
Responsive to increased H+ in CSF(cerebrospinal fluid) or local extracellular fluid
Peripheral Chemoreceptors
Responsive to decreased arterial PO2
Responsive to increased arterial PCO2
Responsive to increased H+ ion concentration. 位于

26. Peripheral Chemoreceptors
R：Carotid bodies
Aortic bodies
adequate stimulus:PO2
PCO2 H+
exciting of breath
depth and frequency Of breath
pulmonary ventilation
glossopharyngeal nerve.
vagus

27. Carbon Dioxide, Oxygen and pH Influence Ventilation (through peripheral receptor)
Peripheral chemoreceptors sensitive to PO2, PCO2 and pH
Receptors are activated by increase in PCO2 or decrease in PO2 and pH
Send APs through sensory neurons to the brain
Sensory info is integrated within the medulla
Respiratory centers respond by sending efferent signals through somatic motor neurons to the skeletal muscles
Ventilation is increased (decreased)

28. Central Chemoreceptor Location
Rostral
Medulla
Caudal
Medulla
Rostral caudal
Ventral Surface of the medulla

29. The sensor neurons are especially excited by H+
H+ are the only direct stimulus for these sensor neurons .

31. Carbon Dioxide Indirect effects through pH as seen previously
CO2 may directly stimulate peripheral chemoreceptors and trigger  ventilation more quickly than central chemoreceptors
If the PCO2 is too high, the respiratory center will be inhibited.

32. arterial Central Chemoreceptor CO2 easily crosses blood-brain barrier
, in CSF the CO2 reacts with water and releases H+,
central chemoreceptors strongly stimulate inspiratory center
arterial
Blood –brain barrier
Central
Chemoreceptor
Carbonic anhydrase
Interstitial fluid cerebrospinal fluid

33. arterial
peripheral
Chemoreceptor
Central
Chemoreceptor

34. arterial
peripheral
Chemoreceptor
Central
Chemoreceptor

35. arterial
peripheral
Chemoreceptor
Central
Chemoreceptor
80%
20%

38. Effects of Hydrogen Ions
Increasing H+ or decreasing PH can faster respiration. It is the effective stimulator to chemoreceptor.
Pathway of H+ regulating respiration
a. H+ in blood increases—excites peripheral chemoreceptor mainly
b. H+ in cerebrospinal Fluid increases-- excites central chemoreceptor

40. toward

44. Oxygen character 1)Hypoxia stimulation act through peripheral
chemoreceptor.
If the inputing of peripheral chemoreceptor
is cut, the stimulation effect disappear.
2)The direct effect of hypoxia to center is
inhibition.
3)hypoxia ：PO2< 80mmHg
ventilation volume increase is been awareness.

45. The pathway of hypoxia regulating respiration:
The main pathway is acting directly on peripheral chemoreceptor and inputting impulse. Respiration center is excited.
Chronic hypoxemia, PO2 < 60 mmHg, can significantly stimulate ventilation
emphysema, pneumonia
high altitudes after several days

46. Brief summary
Central
Chemoreceptor
peripheral
Chemoreceptor

49. Overall Response toPco2, Po2 and pH