Flashcards in Regulation of Respiration Deck (53):
Where are the pontine respiratory centers located?
In the pons.
Which respiratory center establishes the ramp signal?
The dorsal respiratory group.
Where are the medullary respiratory centers, and what groups do they contain?
They are located in the reticular formation of the medulla. They include:
dorsal respiratory group
ventral respiratory group.
What is the usual method for controlling respiration?
It is controlled by PRG signals.
The earlier the ramp ceases, the shorter the duration of inspiration and expiration.
A strong PRG signal results in 30 - 40 breaths/minute
A weak PRG signal results in 3 - 5 breaths/minute
What is the function of the Hering-Breuer inflation reflex?
It is a protective mechanisms to prevent excess inflation of the lungs.
Where does the Hering-Breuer inflation reflex begin?
With stretch receptors in the muscular portions of the walls of the bronchi and bronchioles.
What is apneusis?
The failure to turn off inspiration.
The loss of function of what respiratory group causes apneusis?
pontine respiratory group.
Loss of function causes prolonged insupratory gasping.
Normal function may be to limit lung expansion.
What is chemosensitivity?
A sensitivity to an increase in carbon dioxide levels or a decrease in oxygen levels, which causes decreasted neural activity.
How do the responses of chemoreceptors to hypercapnia or hypoxia differ from responses to these factors by most neurons?
Chemoreceptors increase their rate of activity when hypoxia or hypercapnia occur.
What are the functions of central chemoreceptors?
They are sensitive to [H+], and are indirectly sensitive to carbon dioxide levels in blood (based on pH).
What are the functions of peripheral receptors?
They are sensitive to concentrations of oxygen, carbon dioxide an dhydrogen ions.
They include receptors in the aortic arch and carotid body receptors.
Are peripheral receptors more sensitive to changes in oxygen in the blood or to changes in plasma concentrations of carbon dioxide and hydrogen ions?
more sensitive to changes in oxygen in the blood.
Where are most peripheral chemoreceptors located?
in the carotid bodies at the bifurcation of the common carotids.
Where are some peripheral chemoreceptors located?
In the aortic arch
What are the two types of carotid body cells (peripheral chemoreceptors)?
type I (glomus cells)
type II (sustenacular cells)
What are glomus cells?
They are type I glomus carotid body cells. They have chemosensors and have phosphate-dependent K+ channels that result in an K+ efflux when PO2 is high.
This allows for Ca channels to open, and hence neurotransmitter release.
What are type II carotid body cells?
They are sustenacular cells that play a support role similar to glial cells.
What are the steps of the Hering-Breuer inflation reflex?
Stretch receptors in muscular portions of walls of bronchi and bronchioles receive signals
Dorsal respiratory group neurons receive signals
Inspiratory ramp is inactivated.
What region generates the timing (frequency) of the respiratory rhythm?
Where is the ventral respiratory group located?
In the ventrolateral portion of the medulla.
The rostral jpart of the ventral respiratory group is associated with what complex?
The Botzinger complex.
What is the intermediate part of the ventral respiratory group associated with?
The dilation of the upper airway during inspiration.
The neurons of what respiratory group are almost totally inactive during normal quiet respiration?
ventral respiratory group.
These neurons do not participate in the basing rhythmical oscillation that controls respiration.
What two respiratory centers are located int he pons?
Inspiratory and expiration neurons from the VRG act on what other type of neurons?
spinal motor neurons
Where are DRG neurons found?
Heightened sensitivity to increased levels of carbon dioxide lasts for several hours, but then begins to decline. Whey does this decline occur?
Due to adjustments made by the kidney (they increase bicarbonate levels).
What two groups act on the dorsal respiratory group?
Carotid body receptors
What nerve connects the carotid body receptors to the dorsal respiratory group?
Hering Nerves and CN IX
What nerve connects the aoetic bodies and the dorsal respiratory group?
Chemoreceptors are exposed to PO2 of what type of blood?
What are the functions of PCO2 and H+?
Where are slow-adapting pulmonary stretch receptors located?
Within the airways of the lungs.
What is the function of slow-adapting receptors?
They are sensitive to stretch of airways. Signals from the receptors terminate inspiration and prolong expiration.
They are important in controlling respiration in infants and adults during exercise.
What is the effect of slow-adapting pulonary stretch receptors?
Where are rapidly-adapting pulmonary stretch receptors located?
Within the airways of the lungs.
What are rapidly-adapting pulmonary stretch receptors sensitive to?
irritation, foreign bodies in the airway, and stretch.
What is the effect of rapidly-adapting pulmonary stretch receptors?
Production of a cough.
The receptors override normal respiratory control mechanisms.
Where are J receptors located?
in the alveolar wall in juxtaposition to pulmonary capillaries.
What are J receptors sensitive to?
pulmonary edema (congestive heart failure)
What are the effects of J receptors?
These reflexes override normal respiratory control mechanisms.
What is Cheyne-Stoke breathing?
A cycle in which hyperpnea occurs (elimination of too much carbon dioxide).
If too much carbon dioxide is eliminated, what effect does this have on blood oxygen level?
Blood oxygen level increases
If there is too high of a level of oxygen in the blood, how does this affect transportation of changed pulmonary blood?
There is a delay in transportation of changed pulmonary blood to reach brain.
If there is a delay in transportation of changed pulonary blood to reach the brain, how is ventilation affected?
There will be continued overventilation.
Continued overventilation has what effect on the respiratory center?
There will be a decrease in the function of the respiratory center.
A decrease in excessive depression of the respiratory center leads to what condition?
This then becoms hyperpnea
What is Cheyne-Stokes breathing?
Abnormal pattern of breathing characterized by a repeeating patter of hypernea (rapid breathing) and a temporary stop (apnea)
What is hyperpnea?
A condition with increasingly deeper and rapid breathing.
What is apnea?
A temporary stop in breathing.
What is central sleep apnea syndrome?
A syndrome caused by damage to the central respiratory centers or abnormalities of the respiratory neuromuscular apparatus.