CH387 Lesson 27: Respiratory 4 – Flashcards
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A decrease in PCO2 causes __________ of the bronchioles and __________ of the pulmonary arterioles.
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constriction; dilation
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What area in the brain sets the respiratory rhythm?
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ventral respiratory group (VRG)
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Inspiratory neurons send information to the diaphragm via what nerve?
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phrenic nerve
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What directly stimulates the central chemoreceptors, thus increasing respiration?
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H+ (hydrogen ions)
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As a result of hyperventilation, what will happen to the partial pressures of CO2 (pCO2) and pH?
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decreased pCO2 and increased pH
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Which receptors inhibit inspiration during hyperinflation of the lungs?
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pulmonary stretch receptors
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What stimulates increased respiration at the beginning of exercise?
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sensory input from receptors in joints, neural input from the motor cortex, and other factors
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A homeostatic control mechanism controls respiration. What acts as the effector(s) in this system?
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respiratory muscles
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How should the respiratory system respond to a low blood pH level?
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increase ventilation
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In the model for quiet breathing, expiration is induced by
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abrupt termination of inspiration.
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During active breathing, bursts of action potentials are observed to occur
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asynchronously in the inspiratory and expiratory motor neurons.
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When the blood becomes ________, it can lead to a depression in the activity of the central nervous system.
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acidic
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During quiet breathing, a person's breathing cycle consists of
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contraction and relaxation of inspiratory muscles.
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Peripheral chemoreceptors respond to all EXCEPT which of the following?
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small changes in PO
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Central chemoreceptors are neurons in the medulla that respond directly to changes in
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cerebrospinal fluid pH.
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Chemoreceptors respond primarily to changes in PCO2 indirectly by its effect on
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hydrogen ion concentration.
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Hyperventilation will cause changes in PCO2 that are detected by the chemoreceptors which causes a(n)
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decrease in breathing rate and depth of breathing.
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Which of the following best describes a chemoreceptor response to PO2?
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Central chemoreceptors do not respond to changes in PO2.
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The chemoreceptor reflex regulates ventilation primarily through sensing changes in blood PO2.
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False
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A local bronchodilation within the alveolus will result in a(n) ________ in the ventilation-perfusion ratio in that region. A vasoconstriction of pulmonary arteriole diameter will result in a(n) ________ in the ventilation-perfusion ratio in that region.
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increase : increase
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The resistance of the airways is controlled by bronchioles that are sensitive to changes in PCO2.
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True
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The primary effect of increased PO2 in the lungs is to cause ________ which ________ the ventilation-perfusion ratio back to a normal level.
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vasodilation : decreases
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The primary effect of increased PCO2 in the lungs is to cause ________ which ________ the ventilation-perfusion ratio back to a normal level.
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bronchodilation : increases
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What is the normal pH range for blood?
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7.38-7.42
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Which statement best describes the effect on the body due to pH changes either above or below the normal range?
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Changes in pH can denature proteins that serve as enzymes and receptors throughout the body, resulting in widespread effects on the body.
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How does hemoglobin (Hb) act as a blood buffer?
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Hb can mind H+ following the dissociation of carbonic acid.
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If the peripheral chemoreceptors were damaged, a person would not display respiratory symptoms or dysregulation because the central chemoreceptors would still be in place and would effectively take over moment-to-moment regulation of ventilation.
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False
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The central pattern generator (GPG) __________.
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is responsible for generating the cycle of inspiration and expiration
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Why is blood in the pulmonary artery called mixed venous blood?
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Blood in the pulmonary artery is a mixture of all the blood from the systemic veins so that one can evaluate the total amount of oxygen used and carbon dioxide produced by the whole body and not just one region.
