03a: Regulation Flashcards by Nuna H

Rhythmic firing of neurons controlling respiration can generally modified by:

Chemoreceptors, stretch receptors
Immediate chemical environment
Other control centers
Voluntary control

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Typical neuron associated with (inspiration/expiration) will show augmenting behavior, aka (X).

Inspiration;

X = High AP firing frequency to inspiratory muscles at onset of inspiration, then quickly decreases near end of inspiration

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T/F: the phrenic nerve is one that shows augmenting behavior.

True

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An increase in depth of inspiration can be brought about with which changes in nerve AP?

Increase in frequency (steep uprise in slope)
Recruit more fibers/motor units
Longer “burst” duration

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Increasing AP “burst” frequency will (increase/decrease) tidal volume, (increase/decrease) respiratory frequency, and (increase/decrease) minute ventilation.

Increase, decrease;

Thus, no overall effect on minute ventilation

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Transaction of (X) part of brain stem results in respiratory arrest.

X = below medulla

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List the three major groups of respiratory control center in brain stem.

Dorsal resp group (DRG) in solitary tract nucleus
VRG in medulla
Pneumotaxic (PRG) in upper pons

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(X) group in respiratory control center acts to produce early cutoff for inspiration.

X = pneumotaxic center (pons)

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Removing input from pneumotaxic center is similar to removing input from (X). How is respiratory depth and frequency affected?

X = vagus

Increase depth, decrease frequency

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Apneustic breathing is a result of loss of (X) input. Describe this respiratory pattern.

X = both vagal and pontine

Prolonged inspiratory period, interrupted by brief expiratory gasps

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Hering-Breuer reflex: (X) receptors, activated by (Y), travel in (Z) to (directly/indirectly) stimulate respiratory (on/off) switch.

X = pulmonary stretch
Y = lung inflation
Z = vagus

Indirectly; off

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T/F: there’s a lack of firing of inspiratory neurons during expiration.

True and vice versa

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The thoughts are that respiratory pacemaker may be located in:

Pre-Botzinger complex (rostral portion of VRG)

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Respiration: central chemoreceptors detect (X) and peripheral detect (Y) changes in arterial blood.

X = PCO2
Y = PO2, pH

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Central chemoreceptors located in (X). And peripheral located in (Y).

X = medulla
Y = carotid and aortic bodies

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Effects of gas partial pressures on ventilation are most pronounced when PCO2 (changes/constant) and PO2 (changes/constant).

When they both change reciprocally (I.e. One increases while the other decreases)

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Plot of Pa(CO2/O2) and ventilation is linear.

PaCO2; PO2 less effective at affecting ventilation

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As PaCO2 increases, ventilation continues to (increase/decrease) until (X).

Increase;

PCO2 around 70-80 mmHg (toxic) decrease ventilation

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T/F: inactivating peripheral chemoreceptors has an effect on ventilatory response to PCO2 levels.

False - essentially no effect at all!

Chronic elevation of PCO2, and thus (X) in immediate chem environment of central chemoreceptors, results in compensatory (increase/decrease) (Y).

X = H+
Increase
Y = HCO3-

T/F: central chemoreceptors are immune to sensitivity shifts in chronically high PCO2 levels.

False

T/F: arterial pH changes are not directly capable of affecting central chemoreceptors.

True

(X) peripheral receptors, in (Y) landmark, are more important than (Z) peripheral receptors as respiratory regulators

X = carotid bodies
Y = bifurcation (common to internal/external carotid)
Z = aortic bodies (on aortic arch)

Peripheral chemoreceptors are relatively insensitive to changes in O2 level unless there’s (increase/decrease) more than (X)%.

Decrease;

X = 10

Peripheral chemoreceptors: (X) cells have O2-sensitive (Y) channels that (open/close) with decrease in O2.

X = Type I Glomus Y = K Close (depolarization)

Peripheral chemoreceptors: which ion's (influx/outflux) causes release of transmitters and activation of afferent nerves?

Ca influx (as result of depolarization)

List the lung receptor types that affect ventilation.

1. Stretch (reflex weak in healthy man) 2. Irritant receptors 3. J (juxtacapillary) receptors

Noxious gases (such as ammonia) activates (X) receptors in lung. The effect of this activation is:

X = irritant Bronchoconstriction and hyperpnea (abnormally deep/rapid breathing)

T/F: peripheral chemoreceptors are completely insensitive to PaCO2 changes.

False

T/F: effect of surfactant is dependent on volume of air in lung.

True

T/F: effect of surfactant can be duplicated by a detergent.

False

T/F: hyperventilation affects diffusion rate of gases across alveolar-capillary barrier.

True

Decrease in surfactant will (increase/decrease/not change) FRC.

Decrease (increased recoil force of lungs)

T/F: A decrease in surfactant has no effect P(IP).

False - PIP more negative (hence, pulmonary edema: greater tendency of fluid being pulled from capillaries)

T/F: The end pulmonary capillary PO2 normally equals the PAO2 of the alveoli being perfused.

True

T/F: At end inspiration the PAO2 is equal to the inspired PiO2.

False - PAO2 always lower due to mixing with alveolar gas that has had O2 removed

T/F: In an anemic patient with low Hb, the CO2 content of blood is also affected.

True

(Increase/decrease) in (H/HCO3) of CSF will increase breathing frequency.

Increase in H (potentially as result of) decrease in HCO3

High altitude: how are plasma and urine pH affected?

Initial rise in both

High altitude: arterial PO2 (increases/decreases) and minute ventilation (increases/decreases).

Decreases; increases

T/F: During normal tidal breathing, airway resistance remains constant.

False

PIP becomes more (positive/negative) during inspiration if there's increased airway resistance.

Negative

T/F: At high altitude, the fraction of O2 in air is decreased.

False - fraction stays the same, but atmospheric pressure decreases, so PO2 decreases

Dynamic compression can occur in (inspiration/expiration/both).

Expiration only (Ppleural exceeds Pairway)

T/F: If transport is diffusion-limited, alveolar Pgas will not equal arterial Pgas.

True

T/F: Since O2 transport is perfusion-limited, increasing perfusion will have no effect on the amount of O2 transported to tissues per unit time.

False