Neural regulation

Neural regulation of respiration explaining DRG and VRG neurons mechanism. Explanation of ramp signal and inspiration initiation and termination.
Pneumotaxic center and apneustic center activity. Lesions which affect respiration are mentioned.

1. Neural regulation
of respiration

2. Neural
regulation-
organisation
of the
respiratory
centre
1.Brain
2.Pons
3.medulla

3. Neural
centers-
Respiration
–In PONS(2 imp group of neurons)
–Pneumotaxiccenter (upper pons)
–Apneustic center (lower pons)
–In MEDULLA(3 imp group of
neurons)
–Dorsal respiratory group (DRG)
–Ventral respiratory group (VRG)
–Pre-Botzingercomplex(pacemaker neuron for
respiration

4. Neural
centers-Respiration
Pneumotaxic
center
Apneustic center
Pre-Botzingercomplex
VRGDRG

5. PONS
–Pneumotaxiccenter
–Limit inspiration (increases respiration rate)
–Inhibit apneustic center
–Apneustic center
–Inhibitory neurons (signals to integrator neurons of
DRG)
–Increase tidal volume
–Prolong inspiration
–prevents switching off of inspiratory ramp signals

7. Medulla
–Pre-Botzingercomplex
–Inhalation of respiration
–DRG
–Generates ramp signal
–Results in steady rise in tidal volume
–Made up of: CIA neurons, Integrator neurons and
Inspiratory switch off neurons.
–VRG
–Controls forceful expiration during exercise
–The extra respiratory effort during ex. is called extra
respiration drive or overdrive phenomenon.
–Made up of: Rostalnucleus retrofacialis, Caudal
nucleus retroambiguousandnucleus prambiguous.

8. CIA
NEURONS
OR R
ALPHA
NEURONS

15. INTEGRATION
OF
RESPIRATION-
INSPIRATION
1. INITATION OF INSPIRATION IN MEDULLA
Pre-Botzingercomplex
Spinal cord
C3, C4, C5 nerve roots
Diaphragm, contraction
inspiration
Pre-Botzingercomplex is involuntary so
Respiration is involuntary
ONDINE’S CURSE = absence of pre-botzingercomplex

16. INTEGRATION
OF
RESPIRATION-
EXPIRATION
Passive process
Forceful expiration during exercise
Controlled by VRG
Overdrive phenomenon/ expiration
respiratory drive.

17. 2. MAINTENANCE OF INSPIRATION
Apneustic center
Activates DRG
Ramp signal
Results in steady rise in tidal volume

18. 3. Termination of inspiration
T.V.reaches500 ml
Apneustic center
DRG
PNEUO
TAXICVAGUS
INHIBIT
INHIBIT

19. LESIONS
–Lesions below medulla
–Respiration stops(death)
–No initiation of respiration
–Btw. Pons and medulla (ponto-medullary junction)
–Medulla (see pacemaker, Concerned with initiation)
–Pons ( Regulariserespiration)
–Irregular respiration occurs
–Lesion at mid pons with vaguscut
–Apneusis
–Because no inhibition of apneustic center