Regulation of respiration

1. REGULATION OF
RESPIRATION
SELINA SRAVANTHI
SAROJINI NAIDU VANITA PHARMACY MAHA VIDYALAYA,
TARNAKA, HYDERABAD, TELANAGANA

2. RESPIRATORY
CENTER
 Size of the thorax is altered
by the action of the
respiratory muscles due to
nerve impulses.
 Nerve Impulses are sent
from clusters of neurons in
Medulla Oblongata and Pons
of the Brain.
 Dispersed group of
neurons – Respiratory center
 Respiratory center
Medullary Rhythmicity
area in Medulla Oblongata
Pneumotaxic area in

4. MEDULLARY RHYTHMICITY AREA
Controls the basic rhythm of respiration.
Inspiratory and expiratory areas.

6. PNEUMOTAXIC AREA
 Present in the upper Pons.
 Co-ordinates the transistion between Inhalation and
Exhalation.
Transmit Inhibitory Impulses to the inspiratory area.
Turn off the Inspiratory area before the lungs are too full of air.
Shorten the duration of inhalation
When this area is active- breathing rate is rapid
APNEUSTIC AREA
 Present in the lower Pons.
 Co-ordinates the transistion between Inhalation and
Exhalation.
Transmit Stimulatory Impulses to the inspiratory area.
Activates the Inspiratory area.
Prolong Inhalation – Deep and Long Inhalations
When the pneumotaxic area is active-it over rides signals from
apneustic area

7. REGULATION OF THE RESPIRATORY
CENTER
 CORTICAL INFLUENCE ON RESPIRATION
CHEMORECEPTOR REGULATION OF RESPIRATION
PROPRIOCEPTOR STIMULATION
INFLATION REFLEX

8. CORTICAL INFLUENCE ON
RESPIRATION
 Cerebral cortex connected with respiratory center
Voluntarily alter pattern of breathing
It is protective- prevents water or irritating gases from
entering lungs.
Its is limited by build up of CO2 and H+
Inspiratory area is strongly stimulated- nerve impulse sent
along phrenic and intercostal nerves- inspiratory muscles-

9. CHEMORECEPTOR REGULATION OF
RESPIRATION
 respiratory system is responsive to changes in the level of O2
& CO2
 CHEMORECEPTORS –
Central chemoreceptors- located in
Medulla Oblongata-
Respond to changes in H+ or CO2 concentration or both
in cerebrospinal fluid.
Peripheral chemoreceptors – located in
Aortid bodies- Clusters in wall of arch of aorta-close to
aortic baroreceptors – axons are a part of vagus (X)
nerves
Carotid bodies – oval nodules in the right and left carotid
artery- close to carotid sinus baroreceptors- axons are a

10. CHEMORECEPTOR REGULATION OF
RESPIRATION
 CO2 is lipid soluble- easily diffuses into cells
CO2 + H2O H2CO3 H+ + HCO3
-
PCO2 is 40 mm Hg – increase –
HYPERCAPNIA/HYPERCARBIA – central chemoreceptors are
stimulated.
 peripheral chemoreceptors are stimulated by PCO2 , H+,
deficiency of O2
When PO2 of arterial blood falls from normal 100 mm Hg but
above 50 mm Hg, peripheral chemoreceptors are stimulated.
 the chemoreceptors participate in negative feed back cycle – to
regulate levels
As a result of increased PCO2 decreased pH, decreased PO2 –
inspiratory area highly active- rate and depth of breathing
increases – Hyperventilation.
Carbonic Anhydrase

12. PROPIOCEPTOR STIMULATION
 Before changes in PO2, PCO2 & H+ level, rate of breathing
increases.
Main stimulus is from propiceptors.
Monitor movement of joints and muscles.
Stimulate the inspiratory area of Medulla Oblongata.
INFLATION REFLEX
 Stretch sensitive receptors - baroreceptors/ stretch receptors
located in walls of bronchi and bronchioles.
When stretched due to overinflation – nerve impulses are sent
along Vagus nerve to inspirational areas and apneustic areas –
inhibitted from activating the inspiratory area.
Result- exhalation begins.
During exhalation – lungs deflate- stretch receptor not
stimulated- new inhalation begins.
 inflation reflex/ hering – breuer reflex
Protective reflex.