Diese Präsentation wurde erfolgreich gemeldet.
Wir verwenden Ihre LinkedIn Profilangaben und Informationen zu Ihren Aktivitäten, um Anzeigen zu personalisieren und Ihnen relevantere Inhalte anzuzeigen. Sie können Ihre Anzeigeneinstellungen jederzeit ändern.
Regulation of Respiration
Objectives
• Describe Nervous mechanism of regulation of
respiration & significance of dual control.
• Describe the differ...
Regulation of respiration achieved by two ways or
two mechanisms.
1)Nervous control mechanism,
2)Chemical control mechanis...
Neural regulation of respiration occurs by two
systems:-
a)System responsible for automatic control or
metabolic control o...
Goal of Respiration
• To maintain normal arterial tensions of O2 &
CO2.
• Achieved by maintaining PO2 & PCO2 in alveoli
co...
Pulmonary ventilation =Rate of resp x Depth of resp.
Normally 14-16/min 500ml
(Tidal volume).
So rate & depth of respirati...
•Dual control has great functional significance.
•Involuntary or Automatic control of respiration
allows human to breathe ...
Automatic control of respiration :-It regulates
respiration by several groups of neurons called as
Respiratory centres.
It...
Medullary respiratory centres :- It includes
a)Pre Botzinger Complex(Pace maker cells),
b)Dorsal groups of neurons(DRG) &
...
Pre-BOTC-Pacemaker cells in Pre Bot zinger
complex,IO-Inferior olive, NA-Nucleus Ambiguus
& LRN-Lateral reticular nucleus
NPBL-Nucleus parabrachialis(Pneumotaxic centre),
CP-cerebellar peduncle.
Medullary respiratory centres :-
1)Pre Bot zinger complex :- Situated between
nucleus ambiguus & lateral reticular nucleus...
Responsible for genesis of respiration.
Section or lesion between Pre Bot zinger
complex & phrenic motor neurons i.e betwe...
2)Dorsal respiratory group of neurons(DRG):-
It is situated near & in the nucleus of Tractus
Solitarius.
It has primarily ...
Afferents to DRG:-
1)Peripheral chemoreceptors,
2)Baroreceptors &
3)Several types of receptors in
the lungs.
DRG neurons p...
Functions of DRG :-
1)Spontaneous basic rhythm is generated here.
2)It mainly contains Inspiratory neurons which
emits rhy...
Ramp signal :-It is weak in the beginning , ↑
steadily in ramp manner for 2 sec called as
inspiratory ramp.
Ramp signal ab...
Muscles of expiration need not act, cessation of
activity of inspiratory muscles is enough.
Thus expiration is a passive p...
Inspiratory neurons of DRG are of 3 types:-
1)Central inspiratory activity (CIA) neurons.
Function:-Generate basic respira...
3)Integrator neurons:-They activate the inspiratory
off switch neurons.That means CIA neurons trigger
the IOS neurons thro...
Ventral respiratory group of neurons (VRG):-
In medulla VRG lies 5mm ant & lat to the DRG.
VRG has both types of neurons I...
When the respiratory drive for ↑ pulmonary
ventilation (forceful respiration) is required,
respiratory signals spill from ...
Pontine Respiratory Centres :-They modulate
or modify activity of medullary centres.
1)Apneustic centre: - Situated in low...
It prevents switch off of the inspiratory ramp .
So there is Apneusis (deep & prolonged
inspiration).
This ↑ tidal volume ...
2)Pneumotaxic centre :-Situated in upper part of
Pons in the nucleus parabrachialis.
It sends inhibitory impulses back to ...
By inhibiting Apneustic centre it indirectly controls
the switch off point of inspiratory ramp,thus
controls duration of r...
Thus Apneustic centre & Pneumotaxic centre
regulate the depth & rate of respiration respectively.
Reticular activiting sys...
Genesis of basic rhythm of respiration :-
Pre Bot Zinger complex or according to some
authors Inspiratory neurons of DRG s...
These motor neurons via efferent nerves supply
the muscles of respiration.
Respiratory muscles control movements of chest
...
Motor neurons of spinal cord show reciprocal
innervation.
That means when motor neurons to
inspiratory muscles are active,...
Thus agonist are excited & antagonist are
inhibited.Then vice versa i.e antagonists
activated & agonist inhibited.
All the...
Integrator neurons
Central Inspiratory
Activity (CIA)Inspiratory Off
Switch Neurons
Respiratory
muscles
Cerebral
Cortex
Ap...
DRG
Respiratory
muscles
Cerebral
Cortex
Apneustic
Centre
Vagal
afferentsPneumotaxic
Centre
+
-+
+
+
+__
Genesis of Respira...
Afferent Impulses To Respiratory centres
Respiratory centres
Higher control
Cerebral
cortex
Hypothalamus &
Limbic system
C...
Higher Control(Cerebral cortex)
Voluntary control system.
Pathway:-
Neocortex bypasses medulla
↓
Project directly on spina...
Voluntary control is temporary as chemical
drive overrides the voluntary control system &
respiration is resumed involunta...
Non Chemical Control :-
1)Afferent impulses from Pulmonary stretch
receptors (Hering Breuer inflation inhibiting
reflex) :...
2)Afferent impulses from J-Receptors :
J receptors discovered by an Indian Physiologist
A S Paintal in 1954.
J-receptors(J...
J response is seen as apnoea followed by
hyperventilation, bradycardia, hypotension &
weakness of skeletal muscles.
Physio...
3) Afferent impulses from Irritant receptors
in the mucosa of the respiratory tract :-
They are stimulated by smoke, noxio...
c) Hering Breuer deflation reflex : Deflation of
lungs (Collapse of alveoli) → irritant receptors in
bronchial epithelium ...
Afferent impulses from Proprioceptors (muscles,
joints & tendons) :-During exercise ,change in the
position of different p...
Afferent impulses from Baroreceptors :-
Rise in blood pressure
↓
stimulates baroreceptors
↓
via vagus & glossopharyngeal
n...
Afferent impulses from Thermoreceptors :-
Increase in body temperature
↓
stimulates warm receptors
↓ via
somatic afferent ...
Section D:
Complete transection of the brain stem.
Stops all respiration (Apnoea).No change if vagi
are intact or cut.
Sec...
Section B:
Transection in the midpons :
Pneumotaxic centre cut off from Apneustic
centre. No check over Apneustic centre, ...
Section C :
Transection at Junction of pons & medulla.
Resp continues it is rhythmic (inspiration
followed by expiration) ...
References :
- Understanding Medical Physiology
-By RL Bijlani
-Text book of Medical Physiology
-By Indu Khurana
-Text boo...
Neural regulation of resp by Dr. Mrs Sunita M. Tiwale Professor  Dept of Physiology DYPMC,KOP
Neural regulation of resp by Dr. Mrs Sunita M. Tiwale Professor  Dept of Physiology DYPMC,KOP
Nächste SlideShare
Wird geladen in …5
×

Neural regulation of resp by Dr. Mrs Sunita M. Tiwale Professor Dept of Physiology DYPMC,KOP

426 Aufrufe

Veröffentlicht am

Describe Nervous mechanism of regulation of respiration & significance of dual control.
Describe the different respiratory centres in brain stem with their interconnections & functions.
Describe the genesis of basic rhythm of respiration
Describe the clinical relevance of the nervous control of respiration

Veröffentlicht in: Gesundheit & Medizin
  • Don't forget another good way of simplifying your writing is using external resources (such as ⇒ www.HelpWriting.net ⇐ ). This will definitely make your life more easier
       Antworten 
    Sind Sie sicher, dass Sie …  Ja  Nein
    Ihre Nachricht erscheint hier
  • If you’re looking for a great essay service then you should check out ⇒ www.WritePaper.info ⇐. A friend of mine asked them to write a whole dissertation for him and he said it turned out great! Afterwards I also ordered an essay from them and I was very happy with the work I got too.
       Antworten 
    Sind Sie sicher, dass Sie …  Ja  Nein
    Ihre Nachricht erscheint hier

Neural regulation of resp by Dr. Mrs Sunita M. Tiwale Professor Dept of Physiology DYPMC,KOP

  1. 1. Regulation of Respiration
  2. 2. Objectives • Describe Nervous mechanism of regulation of respiration & significance of dual control. • Describe the different respiratory centres in brain stem with their interconnections & functions. • Describe the genesis of basic rhythm of respiration • Describe the clinical relevance of the nervous control of respiration
  3. 3. Regulation of respiration achieved by two ways or two mechanisms. 1)Nervous control mechanism, 2)Chemical control mechanism.
  4. 4. Neural regulation of respiration occurs by two systems:- a)System responsible for automatic control or metabolic control of respiration:- Situated in brainstem & concerned with O2 delivery & acid base balance. b)System responsible for Voluntary control or behavioural control of respiration:- Located in cerebral cortex.
  5. 5. Goal of Respiration • To maintain normal arterial tensions of O2 & CO2. • Achieved by maintaining PO2 & PCO2 in alveoli constant. • Alveolar ventilation is maintained constant by adjusting Pulmonary ventilation according to the need of the body.
  6. 6. Pulmonary ventilation =Rate of resp x Depth of resp. Normally 14-16/min 500ml (Tidal volume). So rate & depth of respiration is adjusted to maintain normal arterial tensions of O2 & CO2. Regulatory mechanisms adjust the Pulmonary ventilation by controlling the movements of chest.
  7. 7. •Dual control has great functional significance. •Involuntary or Automatic control of respiration allows human to breathe without conscious effort under all circumstances including sleeping & is essential to life. •Voluntary control of respiration facilitates acts like talking, singing, swimming, breath holding & voluntary hyperventilation.
  8. 8. Automatic control of respiration :-It regulates respiration by several groups of neurons called as Respiratory centres. It includes :-1)Medullary respiratory centres, 2)Pontine respiratory centres & 3)Reticular activating system(RAS).
  9. 9. Medullary respiratory centres :- It includes a)Pre Botzinger Complex(Pace maker cells), b)Dorsal groups of neurons(DRG) & c)Ventral groups of neurons(VRG) Pontine respiratory centres :- It includes a) Apneustic centre in lower pons & b) Pneumotaxic centre in upper pons.
  10. 10. Pre-BOTC-Pacemaker cells in Pre Bot zinger complex,IO-Inferior olive, NA-Nucleus Ambiguus & LRN-Lateral reticular nucleus
  11. 11. NPBL-Nucleus parabrachialis(Pneumotaxic centre), CP-cerebellar peduncle.
  12. 12. Medullary respiratory centres :- 1)Pre Bot zinger complex :- Situated between nucleus ambiguus & lateral reticular nucleus. Neurons(Pacemaker cells) are present in it. They discharge spontaneously & rhythmically to phrenic motor neurons of spinal cord.
  13. 13. Responsible for genesis of respiration. Section or lesion between Pre Bot zinger complex & phrenic motor neurons i.e between medulla & spinal cord ceases respiration.
  14. 14. 2)Dorsal respiratory group of neurons(DRG):- It is situated near & in the nucleus of Tractus Solitarius. It has primarily inspiratory neurons → impulses to phrenic motors neurons →Inspiration during quiet breathing.
  15. 15. Afferents to DRG:- 1)Peripheral chemoreceptors, 2)Baroreceptors & 3)Several types of receptors in the lungs. DRG neurons project to Pre Botzinger pacemaker cells. Section or lesion in DRG do not abolish respiratory activity.
  16. 16. Functions of DRG :- 1)Spontaneous basic rhythm is generated here. 2)It mainly contains Inspiratory neurons which emits rhythmical inspiratory discharge. 3)These discharges are called Inspiratory ramp signal which are transmitted to primary inspiratory muscle i.e diaphragm.
  17. 17. Ramp signal :-It is weak in the beginning , ↑ steadily in ramp manner for 2 sec called as inspiratory ramp. Ramp signal abruptly ceases for next 3 sec → turns off the exitation of diaphragm & allows elastic recoil of the lungs & chestwall to cause expiration.
  18. 18. Muscles of expiration need not act, cessation of activity of inspiratory muscles is enough. Thus expiration is a passive process during quiet breathing. Advantage of ramp signal :- Results in steady ↑ in lung volume during respiration rather than inspiratory gasp (abrupt distenion).
  19. 19. Inspiratory neurons of DRG are of 3 types:- 1)Central inspiratory activity (CIA) neurons. Function:-Generate basic respiratory rhythm. 2)Inspiratory Off Switch(IOS) neurons :- Responsible for terminating the respiratory ramp so terminates the excitation of muscles of inspiration.
  20. 20. 3)Integrator neurons:-They activate the inspiratory off switch neurons.That means CIA neurons trigger the IOS neurons through Integrator neurons & thus terminate their own discharge. This forms basic circuit of generation of resp rhythm. CIA + Integrator neurons _ IOS +
  21. 21. Ventral respiratory group of neurons (VRG):- In medulla VRG lies 5mm ant & lat to the DRG. VRG has both types of neurons Inspiratory & Expiratory & have inhibitory connections to each other. These neurons are totally inactive during quiet respiration.
  22. 22. When the respiratory drive for ↑ pulmonary ventilation (forceful respiration) is required, respiratory signals spill from DRG to VRG. Stimulation of I-neurons →Inspiration. Stimulation of E-neurons → expiration. These neurons send signals to accessory muscles of respiration especially during exercise. VRG neurons project to Pre Botzinger Complex. Section or lesion in VRG do not abolish respiratory activity.
  23. 23. Pontine Respiratory Centres :-They modulate or modify activity of medullary centres. 1)Apneustic centre: - Situated in lower part of the pons. Intrinsically active i.e it sends continous impulses to inspiratory neurons of DRG.
  24. 24. It prevents switch off of the inspiratory ramp . So there is Apneusis (deep & prolonged inspiration). This ↑ tidal volume & ↑ duration of inspiration. It also sends impulses to Pneumotaxic centre. Apneustic centre inhibited by the vagus & Pneumotaxic centre.
  25. 25. 2)Pneumotaxic centre :-Situated in upper part of Pons in the nucleus parabrachialis. It sends inhibitory impulses back to Apneustic centre,so Apneustic centre is inhibited & ceases to send impulses to inspiratory neurons in DRG. Pneumotaxic centre keeps the Apneustic centre in check & thus shortens inspiration leading to shallow & more rapid respiratory pattern.
  26. 26. By inhibiting Apneustic centre it indirectly controls the switch off point of inspiratory ramp,thus controls duration of respiration. Strong signals from Pneumotaxic centre ↑ rate of respiration to 30-40/min.
  27. 27. Thus Apneustic centre & Pneumotaxic centre regulate the depth & rate of respiration respectively. Reticular activiting system :-Stimulates the respiratory centres to ↑ respiratory drive by affecting state of alertness or wakefulness of brain. During sleep RAS activity ↓,this ↓ respiratory drive, ↓ Alveolar ventilation so slight ↑ in arterial CO2 tension.
  28. 28. Genesis of basic rhythm of respiration :- Pre Bot Zinger complex or according to some authors Inspiratory neurons of DRG sends spontaneous rhythmic discharge of impulses via white matter of spinal cord (between lateral & ventral corticospinal tracts) reach the motor neurons of spinal cord.
  29. 29. These motor neurons via efferent nerves supply the muscles of respiration. Respiratory muscles control movements of chest & adjust the ventilation according to the requirements of the body.
  30. 30. Motor neurons of spinal cord show reciprocal innervation. That means when motor neurons to inspiratory muscles are active, those for the expiratory muscles are inhibited.
  31. 31. Thus agonist are excited & antagonist are inhibited.Then vice versa i.e antagonists activated & agonist inhibited. All the respiratory centres are bilaterally represented in the brain stem with same sided control & freely communicate with each other.
  32. 32. Integrator neurons Central Inspiratory Activity (CIA)Inspiratory Off Switch Neurons Respiratory muscles Cerebral Cortex Apneustic Centre Vagal afferentsPneumotaxic Centre + + ++ + _ _+ +__ Genesis of Respiration
  33. 33. DRG Respiratory muscles Cerebral Cortex Apneustic Centre Vagal afferentsPneumotaxic Centre + -+ + + +__ Genesis of Respiration
  34. 34. Afferent Impulses To Respiratory centres Respiratory centres Higher control Cerebral cortex Hypothalamus & Limbic system Chemical control Non Chemical control Afferent impulses guide the respiratory centres to regulate the respiration.
  35. 35. Higher Control(Cerebral cortex) Voluntary control system. Pathway:- Neocortex bypasses medulla ↓ Project directly on spinal respiratory neurons ↓ Control respiratory muscles voluntarily ↓ By facilitating acts like talking,singing, swimming, breathholding & Voluntary hyperventilation.
  36. 36. Voluntary control is temporary as chemical drive overrides the voluntary control system & respiration is resumed involuntarily. Hypothalamus & Limbic control system :- Pain & emotional stimuli influence rate & depth of respiration via Hypothalamus & Limbic system. Chemical control system :- Central & Peripheral chemoreceptors influence medullary & pontine respiratory centres.
  37. 37. Non Chemical Control :- 1)Afferent impulses from Pulmonary stretch receptors (Hering Breuer inflation inhibiting reflex) :- Inflation of lungs→stimulates stretch receptors in the smooth muscles of the bronchial tree →through vagus impulses →respiratory centres →inhibition of respiration. This reflex is present in lower animals,when tidal volume exceeds more than 1-1.5 lit. Thus it limits tidal volume. It is protective reflex.
  38. 38. 2)Afferent impulses from J-Receptors : J receptors discovered by an Indian Physiologist A S Paintal in 1954. J-receptors(Juxtapulmonary capillary receptors) very close to capillaries. They are unmyelinated vagal nerve endings stimulated by ↑ interstitial fluid in conditions like Pulmonary congestion , odema, hyperinflation of lungs & chemical irritants.
  39. 39. J response is seen as apnoea followed by hyperventilation, bradycardia, hypotension & weakness of skeletal muscles. Physiological role of J-receptors :-After exercise some fluid is entrapped in the alveolar interstitial space → J receptors stimulated → dyspnoea & ↓ skeletal muscles tone → discourages exercise.
  40. 40. 3) Afferent impulses from Irritant receptors in the mucosa of the respiratory tract :- They are stimulated by smoke, noxious gases & particulate matter in the inspired air. They initiate: a)Cough reflex b)Sneezing reflex
  41. 41. c) Hering Breuer deflation reflex : Deflation of lungs (Collapse of alveoli) → irritant receptors in bronchial epithelium stimulated → yawning, sighing → opening of collapsed alveoli again. d)Deglutation reflex(Protective reflex):Pharyngeal phase of swallowing →receptors send impulses through Glossopharyngeal nerve →resp centres inhibited which prevents entry of food in respiratory tract.
  42. 42. Afferent impulses from Proprioceptors (muscles, joints & tendons) :-During exercise ,change in the position of different parts of the body stimulates proprioceptors→inspiratory neurons stimulated → ↑ rate & depth of respiration. After the delivery of newborn, if the baby doesn’t cry immediately, the paediatrician patt or slap on the back or legs of the baby to initiate its first breath by stimulating resp centres via this reflex.
  43. 43. Afferent impulses from Baroreceptors :- Rise in blood pressure ↓ stimulates baroreceptors ↓ via vagus & glossopharyngeal nerves ↓ inhibites not only vasomotor centre but also respiratory centres ↓ apnoea e.g high doses of adrenaline →adrenaline apnoea.
  44. 44. Afferent impulses from Thermoreceptors :- Increase in body temperature ↓ stimulates warm receptors ↓ via somatic afferent nerves impulses reaches cerebral cortex ↓ stimulates respiratory centres ↓ hyperventilation.
  45. 45. Section D: Complete transection of the brain stem. Stops all respiration (Apnoea).No change if vagi are intact or cut. Section A: Transection above pons (Between pons & midbrain).(Decerebration). Regular breathing continues(Eupnoea). No change if vagi are intact or cut. Inference: Respiratory centres are situated in the medulla & pons.
  46. 46. Section B: Transection in the midpons : Pneumotaxic centre cut off from Apneustic centre. No check over Apneustic centre, so overactive. If vagi are intact they inhibit apneustic centre & resp is regular & rhythmic but slower & deeper. If Vagi are cut –Arrest of resp in inspiration i.e prolonged & sustained inspiration ( Apneusis).
  47. 47. Section C : Transection at Junction of pons & medulla. Resp continues it is rhythmic (inspiration followed by expiration) but irregular. No change if the vagi are intact or cut.
  48. 48. References : - Understanding Medical Physiology -By RL Bijlani -Text book of Medical Physiology -By Indu Khurana -Text book of Medical Physiology -By Guyton & Hall -Text book of Medical Physiology -By A.K.Jain -Review of Medical Physiology -By Ganong -Net Source (Pic & etc.)

×