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24 Cards in this Set
- Front
- Back
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Where is respiration centrally controlled?
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REticular formation in the medulla.
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Where do the nerve fibers that mediate inspiration converge?
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On the phrenic motor neurons located in the ventral horns from C3 to C5 and the external intercostals motor neurons in the ventral horns throughout the thoracic cord.
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Where do fibers concerned with expiration converge?
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Primarily on the internal intercostal motor neurons in the thoracic cord.
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What is the dorsal respiratory group(DRG)?
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Inspiratory cells that may act as the primary rhythm generator for respiratory.
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What stimulates DRG activity?
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1. Low O2 tensions
2. High CO2 tensions 3. Low pH levels 4. Increased electrical traffic in renal artery stenosis(RAS). |
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What nerves mediate input to the DRG?
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Vagus; peripheral chemoreceptors and lung mechanoreceptors
Glossopharyngeal; peripheral chemoreceptors |
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Where does the outflow from DRG project?
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Contralateral phrenic and intercostals motor neurons, and the ventral respiratory group(VRG).
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What makes up the VRG?
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Upper motor neurons of the vagus and the nerves to the accessory muscles of respiration.
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What is the role of the VRG?
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Activated to control expiration when it is an active process (exercise)
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Where is the apneustic center?
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Caudal area of the lower pons.
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What is the significance of the apneustic center?
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Efferent outflow increases the duaration of inspiration.
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Where is the pneumotaxic center?
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Upper part of the pons.
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What is the function of the pneumotaxic center?
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Unknown, it is believed to inhibit the apneustic center, and shortens inspiration. It may play a role in switching between inspiration and expiration.
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How does damage to the pneumotaxic affect respiration?
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Respiration becomes slower and Vt greater.
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Where are central chemoreceptors located?
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Beneath the ventral surface of the medulla.
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What do central chemoreceptors respond to?
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H+ concentration in the CSF and the surrounding interstitial fluid.
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What is the major chemical drive of respiration?
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CO2(H+) effects on the central chemoreceptors.
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Wherre are the peripheral chemoreceptors located/
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Carotid and aortic bodies.
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What do peripheral chemoreceptors respond to?
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1. Lowered O2 tensions
2. Increased CO2 tensions 3. Increased H+ concentrations in arterial blood. |
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What chemical stimuli affect the respiratory center?
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CO2(via CSF and brain interstitial fluid H+ concentration
O2(via carotid and aortic bodies) H+(via carotid and aortic bodies |
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What non chemical stimuli affect the respiratory center?
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Vagal afferents from receptors in the airways and lungs
Afferents from the pons, hypothalamus and limbic center Afferents from proprioreceptors Afferents from baroreceptors |
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Define apnea.
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Cessation of respiration lasting >20seconds.
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What is OSA?
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Obstructive sleep apnea- Recurrent interruptions of breathing during sleep due to temporary obstruction of the airway by lax, excessively bulky or malformed pharyngeal tissues(soft palate, uvula and sometimes tonsils with resultant hypoxemia and chronic lethargy.
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How does OSA differ from central sleep apnea?
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OSA- obstruction with respiratory effort(chest movement)
Central sleep apnea; apnea without respiratory effort. |
