regulation of respiration

chemical control

neural control

automatic control

medullary(central) chemoreceptors

voluntary control

pacemaker cells in medulla

located in the cerebral cortex

activator motor neurons in
the cervical & thoracic spine

sends impulses to the
respiratory motor neurons

respiratory center

the respiratory control pattern generator
responsible for automatic respiration are located
in the medulla

ventral respiratory group
VRG

dorsal respiratory group
DRG

pneumotaxic center

apneastic center

medullar respiratory groups
DRG
VRG

pontine respiratory group
Pneumotaxic C
Apneastic C

neurons within the NTS

The dorsal respiratory group
controls mostly movements
of inhalation and their timing

generates inspiratory "ramp" signals
to the inspiratory muscles
like the diaphram

present within the
nucleus ambigus & nucleus retroambigus

totally inactive during
normal quite respirations

send powerful signals to
abdominal muscles
during heavy exercise

**controls voluntary forced exhalation


& acts to incr the force of inhalation


regulates rhythem of inhalation & exhalation**

Coordinates speed of inhalation
and exhalation

Sends inhibitory impulses
to the inspiratory area

Involved in fine tuning of respiration rate.

controls 'switch off' point of inspiratory ramp

limits the inspiration

secoundarily incr the respiratory rate

located in the lower parts of pons

stimulate the inspiratory center
to incr the respiratory activity

Coordinates speed of inhalation and exhalation.

Sends stimulatory impulses to the
inspiratory area –
activates and prolongs inhalations

Overridden by pneumotaxic control
from the apneustic area to end inhalation

**DRG - cntrls inspiration


VRG - expiration


pneumotaxic - inhibitory imp to inspiratory area


apneastic- stimulatory imp to inspiratory area**

via respiratory chemoreceptors


sensory receptors for the detection of change in
PO2,PCo2,& pH of the blood

peripheral chemoreceptors

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• C02 has potent indirect effect
and permeable to blood-brain barrier.

• H+ ion do not cross blood-brain barrier
less effect on stimulating the chemosensitive neurons.

• Hydrogen (H+) ion is primary and direct stimulus.

• located bilaterally on the
ventral surface of medulla.

• Important for detecting
changes in O2 in the blood.

Respond lesser extent to changes
in blood CO2 and H+ concentration

  1. Carotid bodies
  2. Aortic bodie