Lecture 9: Respiratory Control Flashcards
Chemoreceptors look at O2 levels at the _____ side to determine respiration control
arterial
What are the 4 medullary respiratory centers?
Dorsal respiratory group Ventral respiratory group Pontine respiratory group Botzinger complex Pre Botzinger complex
DRG is located _____
VRG is located _____
Medially
laterally
Brain determines () and () of breathing and sends info to which effectors?
Timing (frequency) and depth (tidal volume/pattern)
Motor neurons that control respiratory muscles
What is the significance of the Pre-Botzinger complex?
Controls respiratory timing by turning on inspiration (basically tells you to inspire again, thus controlling breathing frequency)
What other area helps control respiratory timing?
What happens when this is lesioned?
PRG
Stuck in inspiration (cannot turn it off) = apneusis
What respiratory centers determine breathing pattern/depth aka hard we breath?
DRG
VRG
How does the DRG control breathing depth?
Sensory info (asthma attack, need to breathe hard!) > DRG neurons > send signal to phrenic nerve > contract diaphragm harder because we need to breathe more
The rostral part of the VRG controls () muscles
The caudal part of the VRG controls () muscles
Inspiratory
Expiratory
Apneusis
Characterized by…
Damaged area?
Impaired respiratory rate
PRG
Apnea
Characterized by …
Damaged area?
No input to muscles, not breathing
Medulla (spinal damage)
Chemoreceptors are sensitive to levels of …
Arterial O2, CO2 and pH levels
Under what conditions does chemoreceptor firing rate increase, (tell brain breathing is in trouble)?
High CO2 and H+
Low O2
How do chemoreceptor neurons respond to hypoxia?
Chemoreceptor neurons receptive to hypoxia and ignores metabolic demands to prioritize fixing the breathing.
How do respiratory neurons respond to hypoxia?
Decreases firing rate. So if you don’t have O2, your respiratory neurons don’t tell the muscles to breathe = makes problem worse
Where are central and peripheral chemoreceptors found?
Central: in brain (ventral surface of medulla)
Peripheral: in carotid and aorta
For “drive” to breathe, what receptors do we rely on?
For irregular breathing changes, what receptors do we rely on?
Central
Peripheral chemoreceptors
How do central chemoreceptors work?
Sensitive to CO2 in the brain. CO2 undergoes the dissociation in the brain to H+ and HCO3-. Receptors basically detect increase in H+ in brain (corresponds to how much CO2 entered the BBB)
How do peripheral chemoreceptors work?
Sensitive to decrease in O2 and increase in CO2 and H+ and adjust their firing rate to the medullary respiratory centers
What are pulmonary stretch receptors?
Sensitive to tidal volume by detecting stretch. Purpose is to stop pulmonary system from hyperinflating itself
What are slowly adapting pulmonary stretch receptors?
Which nerve sends info to brain?
End effect?
Located in airways and sensitive to airway stretch.
Sends their info to the brain via Vagus N.
-Inhibit inspiration, prolong expiration
Why are slowly adapting pulmonary stretch receptors strong during infancy and exercise?
Infants: Fetal lungs “used” to being collapsed. More sensitive to stretch.
Exercise: avoid damaging the lungs when breathing hard while exercising
What are rapidly adapting pulmonary stretch receptors?
Which nerve sends info to brain?
End effect?
Located in airways and sensitive to irritation and foreign bodies, as well as stretch
Sends info to brain via Vagus N.
Trigger cough to expel offending object out
What are J (juxtacapillary receptors)?
Which nerve sends info to brain?
End effect?
Receptors near alveolar capillaries that are sensitive to pulmonary edema (lung stiffness)
Vagus N.
Cough, tachypnea (fast and shallow breathing as a way to cope when stiff lungs can’t expand well)
What is the significance of RARs and J Receptors?
Activated during times of distress, so they override normal respiratory controls to prioritize protecting survival
How does the cortex contribute to respiratory control?
Cortex ignores the medulla and sends their info directly to the breathing muscles
