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
- Carotid bodies
- Aortic bodie