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30 Cards in this Set
- Front
- Back
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What does the respiratory control feedback loops involve? |
- mechano-receptors in the lung and chest wall - chemo-receptors in the peripheral circulation - medullary respiratory center in the brainstem - efferents to the inspiratory muscle - draw out the pathway |
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What are the neural control of ventilation respiratory controls in the brainstem? |
- DRG= dorsal respiratory groups: inspiratory neurons - VRG= ventral respiratory groups: inspiratory and expiratory neurons |
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Where are the neurons that generate the respiratory rhythm located? |
- Medullary respiratory center |
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What are the two groups found int he medulla that contain high densities of neurons that fire rhythmically? What is the function? |
- DRG- process sensory input and contain primarily inspiratory neurons - VRG- primarily motor and contains both inspiratory and expiratory neurons, and controls respiration during exercise |
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What are the two centers found in the Pons? What are their function? |
- Apneustic and pneumotaxic - no essential for respiration - modulate respiratory output from the medulla |
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What kind of receptors are involved in the Hering-Breuer reflex? Where are they found? |
- mechano-receptors (pulmonary stretch) stimulated by inflation of the lungs - small airways |
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In the Hering- Breuer reflex what nerves is the afferent limb of this reflex? What is the function? |
- afferent vagus nerve - inhibits inspiratory activity in response to lung distention |
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What is the function of the Hering-Breuer reflex? |
- protects lungs from over-inflation and contributes to the regularity of the respiratory rhythm |
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What 3 structures are involved in maintaining a normal breathing pattern? |
1. Medullary respiratory center 2. Pontine respiratory modulating centers 3. Affterent vagus nerves |
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What kind of effect does the apneustic center have? The pneumotaxic center? |
- apneusitc center: produces a stimulatory effect on inspiratory activity of the medulla respiratory neurons - pneumotaxic center: produces an inhibitory effect on apneustic center activity |
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What kind of effect does the afferent vagus nerve have? |
- produces an inhibitory effect on inspiratory activity of the medullary respiratory center |
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What does bilateral transection (severing) of the vagus nerve result in? |
- decreases respiratory rate, since each inspiration is allowed to last longer |
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Where are irritant receptors located? What simulates these receptors? |
- located in large airways - stimulated by smoke, noxious gasses, and particulates in the inspired air |
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What do the irritant receptors do? |
- initiate reflexes that cause coughing, broncoconstriction, mucus secretion, and breath holding (apnea) |
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What does chronic exposure to inhaled irritants lead to? |
- chronic bronchitis - one of the causes of obstructive lung disease |
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Where are mechanosensitive receptors found? When are they activated? What are they involved in? |
- located in joints and peripheral muscle - activated during movement of limbs - stimulation of breathing during exercise |
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What does the peripheral arterial chemoreceptors monitor? Where does the sensory input come from? |
- monitoring the presence of respiratory gases and metabolites - sensory input from the aortic and carotid bodies |
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What are the two types of cells found in the chemosensitive cells of the carotid body? |
Type I or glomus cell: which are roughly spherical in shape and occur in clusters Type II or sustentacular cells: supporting cells |
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the response of chemoreceptor glomus cells to hypoxia, hypercapnia, and acidosis are all indicators of what? |
elevated metabolic activity |
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What is the common transduction pathway for hypoxia, hypercapnia, and acidosis? |
- inhibition of K+ channels - rise in glomus cell [Ca+2] - release of neurotransmitter |
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Central chemoreceptors are located where? What are they sensitive to? |
- located in the medulla next to the respiratory center - sensitive to changes in CSF |
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What is the path way of increased alveolar ventilation in response to decreased arterial blood pH |
Production of non-CO2 acids > increased arterial [H+] > increased stimulation of peripheral chemoreceptors > increase stimulation of respiratory center in medulla > increase ventilation (hyperventilation) > decrease in arterial PCO2 > return blood pH towards normal |
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Changes in the hydrogen concentration can occur through the production of what? |
- non- CO2 acids such as lactic acids from muscles or from excess fatty acids int he blood with sever diabetes |
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The control of alveolar ventilation by changes in [H+] occurs exclusively where? |
- peripheral chemoreceptors |
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Define eupnea, hyperventilation, hypoventilation, dyspnea, apnea, respiratory arrest |
- eupnea: normal breathing - hyperventilation: rapid and deep respiration - hypoventilation: slow shallow respiration - dyspnea: labored or difficult respiration - respiratory arrest: failure to resume breathing after a period of apnea |
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Asthma |
condition due to hyper-responsiveness and over constriction of the bronchiolar smooth muscle - causes difficulty breathing, especially affecting the inhalation phase of the respiration |
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Athelectasis |
- incomplete expansion fo the lung or a portion of the lung - patient experience varying degree of dyspnea and hypoxia, depending on the extent of the athelectasis |
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Chronic obstructive pulmonary disease (COPD) |
- various combination of asthma, chronic bronchitis, and emphysema - most serious complication of COPD are heart and respiratory failure |
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Emphysema |
- lungs lose their elastic tissue, the walls of alveolar are destroyed and the airways are prone to collapse during exhalation, thereby obstructing the outflow of air - over-inflation of the lung causes a permanently expanded "barrel" chest - alveoli are overly compliant |
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Pneumonia |
inflammation of the lungs in which the alveoli become filled with exudates, therefore, oxygenation decreases and the patient becomes hypoxemia |
