Control of Breathing Flashcards

1
Q

Basic elements of the respiratory control

A

Sensors - chemoreceptors, lung, other
Central controller - brains stem respiratory center
Effectors - respiratory muscles

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2
Q

Components of the respiratory center

A

Pontine respiratory center - apneustic area, pneumonia area
Medullary respiratory center - Ventral respiratory group, dorsal respiratory group

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3
Q

Dorsal Respiratory Group function

A

Controls the frequency of inspiration.
Activates respiratory muscles, via the phrenic nerve by action potential released in 2s bursts.
Inactivation of these neurons allows for passive expiration.

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4
Q

Ventral Respiratory Group function

A

Fire during inspiration with input from the DRG, and are recruited during forceful expiration.

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5
Q

Pneumotaxic area

A

Modulates the apneustic center and sends inhibitory signals to the DRG to shorten inspiration.
Activation increases the breathing rate, but absence has no effect.

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6
Q

Apneustic area

A

Stimulates the DRG t prolong inhalation but is overridden by the pneumotaxic area.
Apneustic breathing = long inspiration and short expiration.

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7
Q

Central chemoreceptors

A

On the ventral surface of the medulla for minute to minute control. Respond to changes in CSF pH.

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8
Q

Peripheral chemoreceptors

A

In the aortic arch and bifurcation of the common carotid arteries. Increase ventilation in response to lowered PO2, increased PCO2, and decreased pH.

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9
Q

Response of central chemoreceptors to pH

A

Low pH, increase breathing.
High pH, decrease breathing.

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10
Q

Effect of breathing low O2

A

Alveolar Po2 decreases, arterial Po2 decreases.
Sensed by peripheral chemoreceptors - fire muscles.
Ventilation increases.

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11
Q

Effect of increasing arterial PCO2

A

pH increases in the arteries and in the CSF
Peripheral and central chemoreceptors are activated.
Respiratory muscles contract and ventilation increases.
PCO2 returns to normal, pH follows suit.

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12
Q

Response to increases in plasma proton concentration

A

Increases pH is sensed by peripheral chemoreceptors, medullary respiratory neurons act.
Muscles contract increasing ventilation
Alv PCO2 decreases, Art PCO2 decreases and pH returns to normal.

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13
Q

Irritant receptors

A

Rapidly adapting pulmonary stretch receptors.
Inhaled dust, smoke, etc, in trachea and large airways.
Myelinated vagal afferents are stimulated and the response is to increase airway resistance - reflex apnea and cough.

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14
Q

Slowly adapting pulmonary stretch receptors

A

Respond to mechanical stimulation by lung inflation. Myelinated vagal afferent stimulated, and expiration becomes long and slow.
COPD patients with inflated chests.

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15
Q

Juxta-alveolar capillary receptors

A

In the alveolar walls, activated by engorgement of the pulmonary capillaries with blood. Acts to increase interstitial fluid volume - increases breathing rate - dyspnea.
Causes; left heart failure, blood back-ups,

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16
Q

Input to DRG

A

Peripheral chemoreceptors via the glossopharyngeal and vagus nerve.
Mechanoreceptors via the lung vagus nerve.