Quiz 6 Regulation of Respiration Flashcards
Where does the most fundamental role in control of breathing take place?
Dorsal respiratory group of neurons located in the Medulla Oblongata.
What area of the brain is responsible for sleep?
Reticular Activating System (RAS)
Which nerves deliver sensory info to the Dorsal Respiratory Group (DRG)?
Glossopharyngeal (IX) and Vagus (X)
What are the 3 sources of peripheral sensory signals that aid in respiration control?
- Peripheral Chemoreceptors
- Baroreceptors
- Lung receptors
What does the Dorsal Respiratory Group (DRG) do?
Controls inspiration and respiratory rhythm
normal rhythmic breathing
Describe the Inspiratory “Ramp” Signal
Motor signal from DRG transmitted to Diaphram
- Weak signal begins to steadily increase in ‘ramp like’ manner for 2 sec to cause diaphragm contraction (inspiration)
- excitatory signal abruptly stops for 3 sec for diaphragm relaxation (expiration)
What is the advantage to having the “ramp” signal to the diaphragm?
Causes a steady increase in inspiratory volume
What can cause the ramp signal to the diaphragm to increase?
exerise
If the ‘ramp’ signal to the diaphram gets shorter (limiting point ceases), what happens to respiration?
The inspiration will get shorter -> shortens duration of inspiration -> increased frequency of respiration
What is the function of the Pneumotaxic Center?
functions to limit inspiratory phase and secondarily leads to increase rate of breathing.
Controls ‘on/off’ of the inspiratory point & shortens entire respiratory cycle
What will the strength of signal from the Pneumotaxic Center do to respirations?
Strong signal - shorter insp phase (0.5 sec) and increased rate (30-40bpm)
Weak signal - long insp phase (5 sec) & reduced rate (3-5 bpm)
What are the 3 groups of neurons that control respiration?
Dorsal Resp Group (DRG)
Pneumotaxic Center
Ventral Resp Group (VRG)
When is the Ventral Resp Group stimulation to breath most likely to occur?
during exercise - during high levels of pulmonary ventilation
Is the VRG active during normal quiet respirations?
No, the DRG is responsible for normal quiet respirations (VRG inactive during this time)
Does VRG contribute to respiratory drive to increase pulmonary ventilation?
Yes, it also stimulates abdominal muscles to assist in forced exhalation
What do experts believe the “Apneustic” Center, located in the lower Pons, function to be?
- Signals the DRG to prevent or retard the ‘switch off’ of the inspiratory ramp stimuli
- works in conjunction with the Pneumotaxic Center to control intensity of inspiration
What is the Hering-Breuer Reflex?
Protective feedback reflex which limits the over inflation of the lungs
- Reflex increases the rate of respiration
What is the ultimate goal of respiration?
maintain proper concentrations of oxygen, CO2, and hydrogen ions in the tissue
Excess ____________ or ___________ ions in the blood act DIRECTLY on the respiratory center to increase strength of insp and exp motor signals
Carbon Dioxde or Hydrogen ions
Does Oxygen have a direct effect on respiratory centers?
No. But it does act on peripheral chemoreceptors.
What peripheral chemoreceptors does oxygen work on?
Carotid and aortic body chemoreceptors
Where is the chemo-sensitive area of brainstem and what does it respond to?
Located in the ventral medulla surface, responds to changes in blood PCO2 and H+ concentration.
How does Hydrogen and CO2 stimulate the chemosensitive neurons in the ventral medulla surface?
Blood H+ do not cross the blood-brain barrier easily. CO2 believed to stimulate the neurons s/t H+ ion concentration.
CO2 will combine with H2O to form carbonic acid which dissociated will form H+ and bicarb. The released H+ will stimulate the resp center activity.
Which has a higher concentration of CO2, the brain or the blood?
both are equal since CO2 easily crosses the BBB.
