47 Questions
What are the three discrete respiratory centers in the medulla oblongata?
DRG, VRG, and pneumotaxic center
Which respiratory center modulates the breathing cycle by extending the length of the medulla to the VRG and sending impulses to the inspiratory muscles?
DRG
The Ventral Respiratory Group (VRG) is located in which part of the medulla?
Nucleus Ambiguus
What is the function of the Apneustic Centre?
Stimulates the DRG and increases "ramp" action potentials. It causes prolonged inspiratory gasps interrupted by transient expiratory efforts (apneusis or apneustic breathing), which is restrained by the pneumotaxic centre and the inflation reflex.
Is the Pneumotaxic Centre essential for breathing? Why?
No, is not essential for breathing. Normal respiratory rhythm can exist in its absence. It acts as a modulator, limiting the activity of the inspiratory DRG by limiting the inspired volume and rate of respiration.
The primary function of the pneumotaxic center is to:
Fine-tune respiratory rate and breathing pattern
When do the expiratory VRG neurons become active?
During forced expiration, exercise, and similar situations.
During which type of breathing are expiratory VRG neurons quiescent?
Tidal breathing
Which division of the VRG provides the inspiratory and expiratory drive to the intercostal muscles?
Caudal division
Which division of the ventral respiratory group (VRG) innervates the ipsilateral accessory muscles of respiration?
Cranial division
What are the consequences of damage to the apneustic center?
Damage to the apneustic center results in an abrupt respiratory cycle, causing irregular breathing patterns and disruptions in the coordination of inspiration and expiration.
What inhibits the activity of the apneustic center?
The apneustic center is inhibited by stretch receptors when maximum inspiration is reached or by the pneumotaxic center, which regulates the duration and intensity of inspiration.
How does the apneustic center contribute to deep breaths?
Sends signals to stimulate the dorsal respiratory group (DRG) and ventral respiratory group (VRG) to increase inspiration and tidal volume, leading to long, deep breaths
What is the effect of the apneustic center on the breathing cycle?
Smooths the breathing cycle and integrates inspiratory cutoff, resulting in prolonged inspiration and increased tidal volume.
Where is the apneustic center located?
Lower pons
What is the effect of increased stimulation of the pneumotaxic center on breathing?
Increased stimulation of the pneumotaxic center leads to faster and shallower breathing.
What happens to the depth of inspiration when the pneumotaxic center is stimulated less, such as in cases of upper pons damage?
When the pneumotaxic center is stimulated less, the depth of inspiration increases.
How does the pneumotaxic center affect the activity of the phrenic nerve?
The pneumotaxic center limits the activity of the phrenic nerve.
Describe the central pattern generation associated with the Ventral Respiratory Group (VRG).
The central pattern generation associated with the Ventral Respiratory Group (VRG) involves a complex interaction of more than six neurons with different firing patterns, concentrated near the pre-Bötzinger complex. It consists of three phases: the inspiratory phase, the post-inspiratory or expiratory phase I, and the expiratory phase II. Excitatory neurotransmitters such as NMDA and inhibitory neurotransmitters such as GABA, along with neuromodulators, play a role in this process.
What is the role of the Ventral Respiratory Group (VRG) in normal, quiet breathing?
It is inactive.
Where are the Apneustic and Pneumotaxic centres located?
Lower Pons
Which of the following is true regarding the Ventral Respiratory Group (VRG)?
It is divided into the Cranial and Caudal Divisions
What is the function of the Pneumotaxic Centre?
It is a modulator that limits the activity of the inspiratory DRG by limiting the inspired volume and rate of respiration
What are the two respratory groups of the Medullary Respiratory Centre?
Dorsal respiratory group (DRG) and the ventral respiratory group (VRG).
Which respiratory center controls both inspiratory and expiratory phases of breathing with a complex interaction of more than six neurons with different firing patterns?
VRG
Which nerve gives motor control to the diaphragm and is formed by rootlets exciting the cervical spine C3, C4, and C5?
Phrenic nerve
Which respiratory center smooths the breathing cycle, integrates inspiratory cutoff, and sends signals for inspiration for long deep breaths by stimulating the DRG and VRG to increase inspiration and tidal volume?
Apneustic center
What happens when the apneustic center is overstimulated?
Gasping (apneusis)
What are the three discrete respiratory centers in the medulla oblongata?
DRG, VRG, and pneumotaxic center
Which respiratory center modulates the breathing cycle by extending the length of the medulla to the VRG and sending impulses to the inspiratory muscles?
DRG
Which respiratory center controls both inspiratory and expiratory phases of breathing with a complex interaction of more than six neurons with different firing patterns?
VRG
Which respiratory center is located in the upper pons, limits inspiration, and controls the rate and depth of breathing?
Pneumotaxic center
Which nerve gives motor control to the diaphragm and is formed by rootlets exciting the cervical spine C3, C4, and C5?
Phrenic nerve
Which respiratory center smooths the breathing cycle, integrates inspiratory cutoff, and sends signals for inspiration for long deep breaths by stimulating the DRG and VRG to increase inspiration and tidal volume?
Apneustic center
What happens when the apneustic center is overstimulated?
Gasping (apneusis)
What are the three discrete CNS respiratory centers in the medulla oblongata?
Dorsal respiratory group, Ventral respiratory group, and Pneumotaxic center
What is the function of the DRG?
Modulates the breathing cycle by extending the length of the medulla to the VRG and sending impulses to the inspiratory muscles
What is the function of the VRG?
Controls both inspiratory and expiratory phases of breathing
What is the function of the pneumotaxic center?
Feeds into the DRG, limits inspiration, and controls the rate and depth of breathing
What is the efferent pathway from the respiratory centers?
Bulbospinal inspiratory neurons that descend from the respiratory center in the anterior part of the lateral column of the spinal cord and terminate in the anterior horn cells of the cervical and thoracic segments
Which spinal cord segments are excited by rootlets forming the phrenic nerves?
C3, C4, and C5
What is the function of the apneustic center?
All of them
What is the function of the Dorsal Respiratory Group (DRG)?
To drive movements and timing of the inspiratory muscles
Where are the neurons of the Dorsal Respiratory Group (DRG) located?
In the nucleus tractus solitarius (NTS)
What is the pattern of inspiratory neuronal action potentials in the Dorsal Respiratory Group (DRG)?
Repetitive 'ramped' bursts of action potentials for 2 secs on and 3 sec off
What is the Ventral Respiratory Group (VRG)?
A group of neurons located in the medulla
What is the Pre-Bötzinger complex?
The central pattern generator for breathing
Study Notes
Initiation of Breathing: Neurogenic Basis and Respiratory Centers
- The initiation of breathing is based on neurogenic processes involving three discrete CNS respiratory centers in the medulla oblongata.
- These centers are the dorsal respiratory group (DRG), ventral respiratory group (VRG), and pneumotaxic center.
- The DRG modulates the breathing cycle by extending the length of the medulla to the VRG and sending impulses to the inspiratory muscles.
- The VRG controls both inspiratory and expiratory phases of breathing with a complex interaction of more than six neurons with different firing patterns.
- The pneumotaxic center, located in the upper pons, feeds into the DRG, limits inspiration, and controls the rate and depth of breathing.
- The efferent pathway from the respiratory centers involves bulbospinal inspiratory neurons that descend from the respiratory center in the anterior part of the lateral column of the spinal cord and terminate in the anterior horn cells of the cervical and thoracic segments.
- The phrenic nerves give the motor control to the diaphragm and are formed by rootlets exciting the cervical spine C3, C4, and C5.
- The pneumotaxic center sends continual inhibitory impulses to the inspiratory center of the medulla oblongata and finely tunes the respiratory rate and breathing pattern by signaling to the DRG.
- The apneustic center, located in the lower pons, smooths the breathing cycle, integrates inspiratory cutoff, and sends signals for inspiration for long deep breaths by stimulating the DRG and VRG to increase inspiration and tidal volume.
- The apneustic center is inhibited by stretch receptors at max inspiration or by the pneumotaxic center.
- Overstimulation of the apneustic center leads to apneusis (gasping) through exciting inspiratory neurons, while damage to the center results in an abrupt respiratory cycle.
- Coordinated activity among the respiratory centers and the efferent pathway is essential for normal breathing and altered breathing rates or depths can result from damage to any of these centers.
Test your knowledge on the initiation of breathing and the neurogenic basis of respiratory centers with this informative quiz! Learn about the three respiratory centers in the medulla oblongata, their functions, and how they work together to control the rate and depth of breathing. Explore the efferent pathway from the respiratory centers and how it controls the diaphragm and phrenic nerves. Take this quiz to discover more about the complex processes that regulate our breathing, and how they can be affected by damage or
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