24 terms

Role of the Respiratory Center

Dorsal Respiratory group
Mainly inspiratory neurons
Send impulses to the motor nerves of the diaphragm and external intercostal muscles
Provides the main inspiratory stimulus during normal quiet breathing
Ventral Respiratory Group
Causes inhalation and exhalation
Active when high levels of pulmonary ventilations are required( Exercise)
Caudal Area of the VRG
Area that stimulates external intercostal and diaphragm
Rostral Area of the VRG
Area that stimulates internal intercostal and abdominal muscles
Inspiratory Ramp Signal
Allows for smooth gradual expansion of the lungs
Steepens during exercise
Pontine Respiratory Centers
Modifies the output of the medullary center
Contains two groups of neurons
Pneumotaxic Group
Primary function is to control inspiratory time
Controls the "switch off" point of the inspiratory ramp
Apneustic Group
Sends signals to the DRG causing apneusis
Breathing pattern characterized by prolonged inspiratory gasp with occasional expirations
Hering-Bruer Reflex Control
Acts as a protective mechanism against excess lung inflation
Important in regulating respiratory rate and depth during exercise
Controlled/ Mediated by the phrenic nerve
Deflation Reflex
Activated with sudden collapse of the lungs (I.E. pneumothorax)
Stimulates strong inspiratory efforts
Head's Paradoxical Reflex
Prevents Atelextasis
Causes Tidal Volumes during exercise
Also Responsible for first breaths of a nerborn
A sensory nerve cell activated by changes in the chemical enviroment surrounding the cell
Central Chemoreceptors
Highly responsive chemosensitive nerve cells located in the medulla
Increase in PCO2
this change in PCO2 will cause hyperventilation
Decrease in PCO2
This Change in PCO2 will cause Hypoventilation
if PCO2 rises above ________ the chemoreceptors response is blunted( Shut Down)
200mls per Minute
The lungs have the ability to eliminate approx how much CO2 per minute
Peripheral Chemoreceptors
Small, highly vascular structures known as the carotid and aortic bodies
Carotid Bodies
Licated bilaterally in the bifurication of the common carotid arteries
Aortic Bodies
Ffound in the Arch of the Aorta
Peripheral Receptors
Come in direct contact with arterial blood where as the central receptors are separated from blood by the CSF
Peripheral Receptors
Stimulated by decreased PaO2(Primary Response), increased PaCO2, and Decreased Arterial pH
Hypoxic Drive
when a patient has a PCO2 of less than 50 the central chemoreceptors shut down, leaving the patient to breath using peripheral chemoreceptors
This May occur if the PO2 is increased over 60mmHg.