28 Questions
What is the primary stimulus for central chemoreceptors in the brain?
Increased H+ concentration
Where are the central chemoreceptors located?
In the medulla
Which chemical factor stimulates peripheral chemoreceptors located at the carotid bodies?
Decreased arterial PO2
What inhibits respiration according to the text?
Decreased H+ in arterial blood
How does metabolic acidosis affect central chemoreceptors?
Stimulates them
What stimulates the respiratory system to increase ventilation of venous return?
Skeletal muscles and joints exercise
What is the primary function of the Ventral Respiratory Group (VRG) in the medulla?
To stimulate the abdominal and internal intercostal muscles during deep expiration
What is the primary function of the Pneumotaxic center in the upper pons?
To inhibit the inspiratory neurons in the DRG and shorten the duration of inspiration
What is the effect of the Hering-Breuer reflex on the respiratory center?
It inhibits the inspiratory center, decreasing the duration of inspiration
Which of the following is NOT a source of afferent input that regulates the function of the respiratory center?
Proprioceptors in the respiratory muscles
What is the primary function of the Apneustic center in the lower pons?
To stimulate the inspiratory neurons in the DRG and prolong the duration of inspiration
Which of the following is the correct sequence of events during the Hering-Breuer reflex?
Lung stretch → Stimulation of stretch receptors → Inhibition of inspiratory center → Decreased duration of inspiration
What is the effect of the inhibition of the Dorsal Respiratory Group (DRG) on the respiratory system?
It leads to relaxation of the diaphragm and external intercostal muscles, resulting in expiration
What is the main role of the medullary centers in the control of respiration?
Generate the basic rhythm of respiration
What is the function of the Pontine centers in the control of respiration?
They modulate the respiratory rhythm generated by the medullary centers
What is the primary function of the peripheral chemoreceptors in the control of respiration?
To detect changes in arterial $P_{O_2}$
How do the peripheral chemoreceptors respond to hypoxia (low $P_{O_2})?
They increase their firing rate, stimulating increased ventilation
What is the ventilatory response to an increase in arterial $P_{CO_2}$?
Ventilation increases to eliminate the excess $CO_2$
What is the primary role of the Ventral Respiratory Group (VRG) in the control of respiration?
To coordinate the activity of the respiratory muscles during expiration
Which of the following is NOT a factor that decreases arterial PO2?
Metabolic acidosis
What is the maximum effect of a decrease in arterial PO2 on ventilation?
5 to 6 times increase
Which of the following statements about the effect of increased arterial PCO2 is correct?
It has a maximum effect of an 11 times increase in ventilation.
Which of the following is responsible for the more powerful response to increased arterial PCO2?
Central chemoreceptors
What is the maximum effect of an increase in arterial H+ concentration on ventilation?
4 times increase
Which of the following is NOT a function of the medullary centers in control of respiration?
Describing the role of pontine centers
Which of the following statements is correct regarding the stimulation of peripheral chemoreceptors?
They are stimulated by hypoxia.
Which of the following is NOT a factor that increases arterial PCO2?
Metabolic alkalosis
What is the maximum effect of an increase in arterial H+ concentration on ventilation compared to the effect of an increase in arterial PCO2?
Less than the effect of increased PCO2
This quiz covers the neural mechanisms involved in controlling respiration, including the role of medullary and pontine centers. It also discusses the types of chemoreceptors, the mechanism of peripheral chemoreceptors stimulation by hypoxia, and the respiratory responses to changes in blood gases.
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