Respiratory Control Flashcards
List the four major respiratory centers in the brainstem
- Pre-Botzinger
- Pontine respiratory group
- Dorsal respiratory group
- Ventral respiratory group
Describe the four major respiratory centers in the brainstem, comparing and contrasting their locations and hypothesized roles in respiratory control
- Pre-Botzinger-Location?
- Role in respiratory control?
- Located in the medulla
- Generates “core” rhythm
Pontine respiratory group
- location? - Role in respiratory control?
- Located in the pons
- Modifies inspiratory timing (activity–>turns off inspiration)
Dorsal respiratory group
- Location?
- Role in respiratory control?
- Located in the medulla
- Controls depth of breathing (tidal volume)
Ventral respiratory group
- Location? - Role in respiratory control?
- Located in the medulla
- Controls inspiration, expiration, and depth
Compare and contrast apneusis and apnea
-Apneusis-appearance?
Maintained inspiratory discharge
-Apneusis-results from?
Pontine damage
Apneusis-Effects?
Slight delay, but then increased CO2, decreased O2, and death if not supported
Apnea-Appearance?
Absence of respiratory effort (no inspiration)
Apnea-results from?
Medullary or spinal damage
Apnea-Effects?
Increased CO2, decreased O2, death if not supported
Chemoreceptor
A neuron that is sensitive to specific chemicals (In the respiratory system-CO2, O2, and H+)
Changes in the concentrations of these chemicals will change the firing rate of a chemoreceptor
What happens to the firing rate of chemoreceptors when CO2 is increased?
The firing rate of chemoreceptors increases with increased CO2
What happens to the firing rate of chemoreceptors when O2 is decreased?
The firing rate of chemoreceptors increases with decreased O2
What happens to the firing rate of chemoreceptors when H+ is increased?
The firing rate of chemoreceptors increases with increased H+
What is the normal response of a respiratory neuron (or any neuron) to an increase in CO2 or a decrease in O2?
A decrease in activity-which would decrease ventilation, decreasing gas exchange and making the problem worse
Define chemosensitivity
- The ability of certain chemicals to change the firing rate of specific neurons
- In the respiratory system, there are neurons sensitive to CO2, O2, and H+
How do chemoreceptors respond to hypoxia or hypercapnia?
Their activity increases which activate the respiratory centers to increase respiration
There are two sets of chemoreceptors
-Where are they each located??
- The central chemoreceptors (in brain)
- The peripheral chemoreceptors (in carotid and aorta)
- They each have a different role in the control of ventilation
Central chemoreceptors
- Where are they located specifically?
- What are they sensitive to?
-They are located on the ventral surface of the medulla
-They are indirectly sensitive to CO2 in the blood
CO2 crosses the BBB and reacts with water via carbonic anhydrase to give H2O and CO2 then H2CO3 then H and HCO3
Central chemoreceptors
-main function??
“Drive to breathe”-Make you breathe regularly
Peripheral chemoreceptors
- Where are they located specifically?
- What are they sensitive to?
- They are located in the aortic arch and carotid body
- They are sensitive to O2, CO2, and H+
Peripheral chemoreceptors: oxygen sensitivity
- Increased firing rate of afferents from carotid body/aortic arch
- CO2 and pH also stimulate the same response but the response is quicker than with central
- Increased firing rate and tidal volume
Compare and contrast the central and peripheral chemoreceptors
-Central chemoreceptors-Location?
Ventral surface of brainstem
Central chemoreceptors-What are they sensitive (directly and indirectly) to?
Directly: pH of CSF
Indirectly: CO2 in plasma
Central chemoreceptors-influence?
“respiratory drive”-drive to breathe
Central chemoreceptors-effects?
Increased respiratory rate/depth in response to hypercapnia (slower than peripheral)
Peripheral chemoreceptors-Location?
Aortic arch and carotid body
Carotid body
Dopamine
Peripheral chemoreceptors-What are they directly sensitive to?
O2, CO2, and H+ (pH)
Peripheral chemoreceptors-Influence?
Acute changes in blood gases
Peripheral chemoreceptors-Effects?
Increased respiratory rate/depth in response to hypercapnia, hypoxia, or acidosis
Compare and contrast the mechanoreceptor inputs that influence respiration
-Slowly adapting PSR (SARs)-Location?
Airways
-Slowly adapting PSR (SARs)-Adequate stimulus?
Stretch of lung
-Slowly adapting PSR (SARs)-Effect?
Inhibit inspiration/promote expiration
-Slowly adapting PSR (SARs)-Role in infants and adults?
In infants-every breath
In adults-exercise or other high Vt times
-Rapidly adapting (RARs)-location?
airways
-Rapidly adapting (RARs)-adequate stimulus?
irritants
-Rapidly adapting (RARs)-effect?
cough to clear airway
-Rapidly adapting (RARs)-role?
Protective (not every breath)
J receptors-location?
Near capillaries in alveoli
J receptors-adequate stimulus?
pulmonary edema
J receptors-Effect?
Cough, tachypnea
J receptors-role?
Protective (not every breath)
Cortical influences on breathing
In these cases, the cortex appears to bypass the medullary centers completely and send input directly to the muscles of inspiration
