25 Questions
What is the primary function of the pneumotaxic center in respiration?
To control the 'switch-off' point of the inspiratory ramp
What is the role of the ventral respiratory group of neurons during normal quiet respiration?
Remain almost totally inactive
What is the function of the Hering-Breuer inflation reflex?
To stop further inspiration
How do excess carbon dioxide or excess hydrogen ions in the blood affect respiration?
Cause greatly increased strength of both the inspiratory and the expiratory motor signals to the respiratory muscles
Where are the peripheral chemoreceptors located?
Carotid and aortic bodies
What is the role of oxygen in controlling respiration?
Acts almost entirely on peripheral chemoreceptors
What is unique about hydrogen ions in stimulating sensory neurons in the chemosensitive area?
They have a potent direct stimulatory effect on respiration
Where is the chemosensitive area located in the respiratory center?
Lying 0.2 millimeter beneath the ventral surface of the medulla
Where is the respiratory center located in the brain?
Medulla oblongata and pons
Which group of neurons is responsible for mainly causing expiration?
Ventral respiratory group
What is the main function of the pneumotaxic center?
Controlling rate and depth of breathing
Where are most of the neurons of the dorsal respiratory group located?
Nucleus of the tractus solitarius (NTS)
What serves as the sensory termination for transmitting signals into the respiratory center?
Both the vagal and glossopharyngeal nerves
Which group of neurons plays the most fundamental role in the control of respiration?
Dorsal respiratory group
What is responsible for generating the basic rhythm of respiration?
Dorsal respiratory group
'The nervous signal transmitted to the inspiratory muscles is not an instantaneous burst of action potentials.' What part of the respiratory center does this refer to?
Dorsal respiratory group
What is the chronic effect of a change in blood carbon dioxide concentration on respiratory drive after a few days' adaptation?
It decreases to about one fifth the initial effect
Where are the carotid bodies located?
In the bifurcations of the common carotid arteries
What is the physiological response when the oxygen concentration in arterial blood falls below normal?
The chemoreceptors become strongly stimulated
What is the consequence of chronic breathing of low oxygen?
The alveolar ventilation often increases 400 to 500 per cent after 2 to 3 days of low oxygen
What is the role of pulmonary irritant receptors in the trachea and bronchi?
They stimulate bronchial constriction in diseases like asthma and emphysema
What may give a person a feeling of dyspnea (shortness of breath)?
Engorgement of pulmonary capillaries with blood
What is the most prevalent cause of respiratory depression and respiratory arrest?
Overdosage with anesthetics or narcotics
Where are the aortic bodies located?
Along the arch of the aorta
What happens to the activity of the respiratory center in the brain stem within 2 to 3 days of chronic breathing of low oxygen?
It loses about four fifths of its sensitivity to changes in Pco2 and hydrogen ions
Test your knowledge about the respiratory center, which is composed of several groups of neurons located in the medulla oblongata and pons of the brain stem. Learn about the major collections of neurons and their functions in controlling inspiration and expiration.
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