The document details the neural regulation of respiration, highlighting the organization of various brain centers involved in the respiratory process, including the pneumotaxic and apneustic centers in the pons and the dorsal and ventral respiratory groups in the medulla. It explains the roles of these centers in initiating and maintaining normal breathing, as well as their functions in situations requiring increased respiratory effort, such as during exercise. Lesions in different brain areas can lead to severe respiratory issues, including cessation of breathing.

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)
– Pneumotaxic center (upper pons)
– Apneustic center (lower pons)
–In MEDULLA (3 imp group of
neurons)
– Dorsal respiratory group (DRG)
– Ventral respiratory group (VRG)
– Pre-Botzinger complex (pacemaker neuron for
respiration

4. Neural
centers-
Respiration
Pneumotaxic
center
Apneustic center
Pre-Botzinger complex
VRG
DRG

5. PONS
–Pneumotaxic center
– 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-Botzinger complex
– 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: Rostal nucleus retrofacialis, Caudal
nucleus retroambiguous and nucleus prambiguous.

8. CIA
NEURONS
OR R
ALPHA
NEURONS

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

16. INTEGRATION
OF
RESPIRATION-
EXPIRATION
Passive process
Forceful expiration during exercise
Controlled byVRG
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.reaches 500 ml
Apneustic center
DRG
PNEUO
TAXIC
VAGUS
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 ( Regularise respiration)
– Irregular respiration occurs
– Lesion at mid pons with vagus cut
– Apneusis
– Because no inhibition of apneustic center