Respiratory - Pt 3 Control of Respiration Flashcards
CO2 + [] <–> H2CO3 <–> H+ + []
What enzyme catalyzes the left side of this equation?
H2O; HCO3-
Carbonic Anhydrase
90% of the CO2 in our bodies moves around as []
HCO3-
Peripheral Chemoreceptors detect concentration changes in which molecules?
Oxygen, CO2, pH (H+)
The body is much more sensitive to [] concentrations than [] concentrations.
CO2; Oxygen
What are the 4 components, in the brain stem, for controlling breathing?
Chemoreceptors for O2, CO2, and H+
Mechanoreceptors in teh lungs and joints
Control centers in the medulla and pons
Respiratory muscles
The pontine respiratory group (PRG) plays the main role in modulating respiration. What are the 2 parts to the PRG and what does each do?
- Apneustic center: drives inspiration and can prolong inspiration by prolonging the period of action potentials in the phrenic nerve.
- Pneumotaxic Center: fine tunes the switch between inspiration and expiration and can limit action potentials sent down the phrenic nerve.
Apneustic center: drives [] and can prolong inspiration by [] the period of [] [] in the phrenic nerve.
Apneustic center: drives inspiration and can prolong inspiration by prolonging the period of action potentials in the phrenic nerve.
Pneumotaxic Center: fine tunes the switch between [] and [] and can limit action potentials sent down the [] nerve.
Pneumotaxic Center: fine tunes the switch between inspiration and expiration and can limit action potentials sent down the phrenic nerve.
T/F
CO2 and O2 concentrations are monitored by central chemoreceptors?
FALSE
Only Blood CO2 levels, and interstitial H+, are monitroed by central chemoreceptors.
T/F
Central chemoreceptors indirectly sense the blood H+ concentrations?
FALSE
Central chemoreceptors indirectly sense the interstitial H+ levels.
Decreases in the pH of CSF produce [] in breathing rate ([] , and increases in the pH of CSF produce [] in breating rate ([] ).
Decreases in the pH of CSF produce increases in breathing rate (hyperventilation), and increases in the pH of CSF produce decreases in breating rate (hypoventilation).
How do central chemoreceptors indirectly monitor H+ levles?
- H+ does not cross the blood brain barrier. However, CO2 does.
- So when the PCO2 increases in the arteries, the PCO2 will increase in the CSF. In the CSF CO2 will convert to H+ and HCO3-…thus increasing the levels of H+ in the CSF.
- The chemoreceptors would detect this change and increase breathing rate to raise pH levels.
Each of the following are detected by peripheral chemoreceptors and produces an increase in breathing rate:
- [] in arterial PO2
- [] in arterial PCO2
- [] in arterial pH
- decrease in arterial PO2
- increase in arterial PCO2
- increase in arterial pH
Ventral respiratory group (VRG): contain [] generators whose otuput drives [].
Ventral respiratory group (VRG): contain rhythm generators whose otuput drives respiration.
The Dorsal Respiratory group (DRG) could also be called the respiratory []. It integrates and modifies rhythms generated by the [].
The Dorsal Respiratory group (DRG) could also be called the respiratory control center. It integrates and modifies rhythms generated by the VRG.
What 2 “groups” in the medulla control breathing? Which one actually initiates the response in breathing? (bolded on the backside of card)
Ventral respiratory group (VRG)
Dorsal respiratory group (DRG)
The [] and [] [] [] send their signal to the DRG which then control the rhythms genreated by the []
- chemoreceptors
- Pontine respiratory group
- VRG
What 3 factors influence breathing rate and depth?
- Pulmonary irritant reflexes
- Lung stretch Receptors
- Chemical Factors
Pulmonary Irritant reflexes
- Locted between [] cells lining airways and send info to medulla via the [] [] (cranial 10)
- Cause a reflex [] of bronchial smooth muscle and an [] in breathing rate.
- Located between epithelial cells lining airways and send info to medulla via the vagus nerve (cranial 10)
- Cause a reflex constriction of bronchial smooth muscle and an increase in breathing rate.
Lung Stretch Receptors:
- [] present in the smooth muscle of the airways
- stimualted by [] of the lungs and airways
- initiate a reflex [] in breathing rate called [] reflex
- Decreases breathing rate by prolonging [].
- Mechanoreceptors present in the smooth muscle of the airways
- stimulated by distention of the lungs and airways
- initiate a reflex decrease in breathing rate called Hering-Breur reflex
- Decreases breathing rate by prolonging expiratory time.
Chemical factors that influence breathing rate:
- Increased CO2 (hypercapnia) causes a [] in pH
- This stimulates []
- Increased CO2 (hypercapnia) causes a decrease in pH
- This stimulates hyperventilation
What is the airflow equation? What does each variable represent?
V = (delta)P/R
- V = airflow (L/min)
- (delta)P = Pressure gradient (mmHG)
- R - AIrway resistance
V (airflow) and resistance are [] related.
V (airflow) and resistance are inversely related.
What are the 3 physical factors influencing pulmonary ventilation?
- Airway resistance
- Alveolar surface tension
- Lung Compliance
- If airway resistance decreases…what happens to airflow?
- If alveolar surface tension increases….what happens ot airflow?
- airflow increases
- airflow decreases
[] is the major non elastic source of resistance to gas flow
friction
What is the equation for the Law of LaPlace?
What does each variable stand for?
P = 2T/r
- P - collapsing pressure on alveolus
- T - surface tension
- r - radius of alveolus
T/F
The 2T/r portion of Law of LaPlace can be thought of as the pressure required to keep the alveolus open.
True!
Surface tension:
Resists an force that tends to [] the sruface area of the liquid.
increase
T/F
Surfactant is more useful in large alveoli and not small alveoli?
FALSE
Small alveoli are close together which increases the effects of surface tension. So these smaller alveoli need surfactant moreso than larger ones.
Lung Compliance: a measure of the change in lung [] that occurs with a given change in [] pressure
Volume
transpulmonary
Lung Compliance:
- Normally high due to
- [] of the lung tissue
- [] alveolar surface tension
- Diminished by
- []-[] scar tissue (fibrosis)
- Reduced production of []
- Decreased [] of the thoracic cage
- Normally high due to
- Distensibility of the lung tissue
- Decreased alveolar surface tension
- Diminished by
- Non-elastic scar tissue (fibrosis)
- Reduced production of surfactant
- Decreased flexibility of the thoracic cage
Increasing lung compliance [] the collapsing force at any given volume so that it is [] for the lungs to expand.
Reduces
Easier
T/F
The lungs are less compliant at the base of the lung relative to the apex of the lung.
FALSE
The apex of the lung is already stretched, we know this, so it would make sense that the base of the lung has more “stretchyness” available to it.
[] [] [] is the volume of inspired air in the conducting zone conduits. It is roughly [] mL
Anatomical Dead Space
150mL
Functional Dead Space is when alveoli cease to act in [] [] due to collapse or obstruction or []/[] mismatch.
Functional Dead Space is when alveoli cease to act in gas exchange due to collapse or obstruction or ventilation/perfusion mismatch.
T/F
Of the 500mL of air that are exchanged through Tidal Volume, only rougly 150mL of that air actually reach the alveoli for gas exchange.
FALSE
only about 350 mL of air reach the alveoli. 150 mL stay inside the anatomical dead space.
T/F
For someone with emphysema, it is easier to inspire and harder to expire.
TRUE
Some suffering from emphysema would experience a [] FRC.
larger
Somone suffering from pulmonary fibrosis (or a [] disease) would experience difficulty [] and a [] FRC and Total Lung Capacity.
Somone suffering from pulmonary fibrosis (or a restrictive disease) would experience difficulty inhaling and a lower FRC and Total Lung Capacity.
T/F
Somone suffering from astma/Emphysema and Pulmonary Fibrosis would have a lower FEv1 than normal individuals.
TRUE.
Someone suffering from a restrictive disease would be able to exhale []-[]% of their [] within 1 second of exhaling.
Someone suffering from a restrictive disease would be able to exhale 90-95% of the FVC within 1 second of exhaling.
Which individual is able to expire more of their FVC within the first second of exhaling…
- Normal Individual
- Individual suffering from an obstructive disease
- Individual suffering from a restrictive disease
- Individual suffering from a restrictive disease
These people can blow off 90-95% of their FVC
