Respiratory System - Brainstem & Nerves

from respiratory powerpoint; Ahangari physio exam 4 (PCB3703C)

What is the main function of the respiratory control centers?

Coordinate sensory information and control respiratory muscles to regulate breathing.

What variables are monitored to control breathing?

PO2, PCO2, and H+ concentration.

What are the two major types of chemoreceptors involved in respiratory control?

Central chemoreceptors and peripheral chemoreceptors.

Where are central chemoreceptors located?

In the medulla.

Where are peripheral chemoreceptors located?

In the carotid bodies and aortic bodies.

What stimulates central chemoreceptors?

Primarily increased CO2 and increased H+.

What stimulates peripheral chemoreceptors?

Decreased PO2, increased PCO2, and increased H+.

What is the strongest stimulus for breathing under normal conditions?

Increased PCO2.

What happens to ventilation when arterial PCO2 increases?

Ventilation increases.

What happens to ventilation when arterial H+ increases?

Ventilation increases.

What happens to ventilation when arterial PO2 decreases?

Ventilation increases.

What other receptors besides chemoreceptors help regulate breathing?

Lung stretch receptors, irritant receptors, J receptors, and joint and muscle receptors.

Where is sensory information for breathing coordinated?

In the brainstem.

What does the brainstem use sensory information for?

To control respiratory muscles and the breathing cycle.

What is the medullary respiratory center and where is it located?

The main respiratory center located in the reticular formation of the medulla.

What is the dorsal respiratory group (DRG)?

The primary inspiratory center in the medulla.

What is the main function of the dorsal respiratory group?

Control inspiration.

What nerves provide input to the dorsal respiratory group?

The vagus nerve and glossopharyngeal nerve.

What information does the vagus nerve carry to the DRG?

Information from peripheral chemoreceptors and lung mechanoreceptors.

What information does the glossopharyngeal nerve carry to the DRG?

Information from peripheral chemoreceptors.

Where does output from the dorsal respiratory group travel?

To the diaphragm through the phrenic nerve.

What nerve stimulates the diaphragm during inspiration?

The phrenic nerve.

What muscle is directly stimulated by the phrenic nerve?

The diaphragm.

What is the ventral respiratory group (VRG)?

A respiratory center primarily responsible for expiration.

What is the main function of the ventral respiratory group?

Active expiration.

Is the ventral respiratory group active during quiet breathing?

No, because normal expiration is passive.

When does the ventral respiratory group become active?

During exercise or increased respiratory effort.

Which respiratory center is responsible for active expiration during exercise?

The ventral respiratory group.

Where is the apneustic center located?

In the lower pons.

What is the function of the apneustic center?

Stimulates inspiration.

What happens when the apneustic center is strongly stimulated?

Produces a deep prolonged inspiratory gasp known as apneusis.

Where is the pneumotaxic center located?

In the upper pons.

What is the function of the pneumotaxic center?

Inhibits inspiration.

How does the pneumotaxic center affect respiratory rate?

It regulates inspiratory volume and respiratory rate by limiting inspiration.

Which center promotes inspiration: apneustic or pneumotaxic?

Apneustic center.

Which center inhibits inspiration: apneustic or pneumotaxic?

Pneumotaxic center.

How do the apneustic and pneumotaxic centers work together?

The apneustic center stimulates inspiration while the pneumotaxic center limits inspiration.

Can breathing be voluntarily controlled?

Yes.

What are examples of voluntary control of breathing?

Hyperventilation and breath-holding.

Why can a person not hold their breath forever?

Rising PCO2 and falling PO2 eventually stimulate breathing.

What extends the period of breath-holding?

A period of hyperventilation beforehand.

Why does hyperventilation extend breath-holding time?

Because it lowers PCO2 before breath-holding begins.

What happens to PCO2 during breath-holding?

PCO2 rises.

What happens to PO2 during prolonged breath-holding?

PO2 falls.

Which respiratory center receives input from the vagus nerve?

The dorsal respiratory group.

Which respiratory center receives input from the glossopharyngeal nerve?

The dorsal respiratory group.

What type of information do lung mechanoreceptors provide?

Information about lung stretch and mechanics.

What is the primary inspiratory center of the brainstem?

The dorsal respiratory group.

What center is most responsible for expiration during exercise?

The ventral respiratory group.

What is the relationship between increased CO2 and respiratory drive?

Increased CO2 strongly increases respiratory drive.

What receptor type is most important for detecting decreased oxygen levels?

Peripheral chemoreceptors.

Which chemoreceptors are located in the carotid bodies?

Peripheral chemoreceptors.

Which chemoreceptors are located in the aortic bodies?

Peripheral chemoreceptors.

Which chemoreceptors are located in the medulla?

Central chemoreceptors.

What is the respiratory response to increased H+ concentration?

Increased ventilation.

What is the respiratory response to decreased PO2?

Increased ventilation.

What is the respiratory response to increased PCO2?

Increased ventilation.

What is apneusis?

A prolonged inspiratory gasp caused by apneustic center stimulation.

Which structure serves as the final effector for inspiratory signals from the DRG?

The diaphragm.

What pathway carries inspiratory output from the medulla to the diaphragm?

DRG to phrenic nerve to diaphragm.