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APHY 201 Exam 4b1
Ch. 16 Drills - Harder Questions
| Question | Answer |
|---|---|
| What is the difference between intrapulmonary and intrapleural pressure called? | It is called transpulmonary pressure. |
| What is the function of transpulmonary pressure? | It keeps the lungs pressed up against the thoracic wall and allows the lungs to expand during inspiration. |
| What is the term for the change in lung volume per change in transpulmonary pressure? | lung compliance |
| What is the term for the ease with which the lungs expand under pressure? | lung compliance |
| When does elastic tension in the lungs increase and decrease? | Tension increases during inspiration and is reduced by elastic recoil during expiration. |
| How is fluid balance maintained in the alveolar epithelial cells? | Fluid from blood capillaries is absorbed by osmosis driven by the active transport of Na+, and secreted by the active transport of Cl-. |
| How does surface tension affect the alveoli? | Surface tension raises the pressure of the alveolar air and acts to collapse the alveolus. |
| What is surfactant composed of? | Surfactant consists of hydrophobic protein and phospholipids. |
| How does surfactant reduce surface tension? | It reduces surface tension between water molecules by reducing the number of hydrogen bonds between them. |
| What are two major functions of surfactant in the lungs? | Surfactant prevents the collapse of alveoli upon expiration and allows a residual volume of air to remain in the lungs. |
| What causes acute respiratory distress syndrome (ARDS) in adults? | ARDS in adults can be caused by sepsis or pneumonia. |
| How does ARDS affect lung function? | Protein-rich fluid fills the lungs, reducing lung compliance and surfactant production, which produces hypoxemia. |
| (starred) Which muscles work with the external intercostals to perform inspiration? | The parasternal intercostal muscles, also called the interchondral part of the intercostal muscles, work with the external intercostals to perform inspiration. |
| (starred) Which muscles are considered the accessory muscles used for forced inspiration? | The scalenes, pectoralis minor, and sternocleidomastoid are used for forced inspiration. |
| How does the thoracic cavity volume decrease during forced expiration? | The internal intercostals, excluding the interchondral part, contract to lower the ribs. |
| How much does intrapulmonary pressure decrease during forced inspiration? | Aided by accessory muscles, forced inspiration decreases intrapulmonary pressure to -27 cmH2O or lower. |
| How much does intrapulmonary pressure increase during forced expiration? | |
| In which kind of lung disorder is the lung tissue is damaged and vital capacity is reduced, but the forced expiratory volume (FEV) rate remains normal? | restrictive lung disorder |
| Examples include pulmonary fibrosis and anthracosis, also known as black lung disease. | |
| In which type of lung disorder can lung tissue and vital capacity can be normal, but forced expiration is reduced, making it hard to expel air? | obstructive lung disorder |
| What are examples of obstructive lung disorders? | Examples include asthma, chronic emphysema, and chronic obstructive bronchitis. |
| What triggers allergic or atopic asthma? | Allergic asthma is triggered by allergens that stimulate T lymphocytes to secrete cytokines and recruit eosinophils and mast cells, causing inflammation and producing IgE antibodies. |
| What conditions are included under Chronic Obstructive Pulmonary Disease (COPD)? | COPD includes emphysema and chronic obstructive bronchiolitis, characterized by chronic inflammation, airway narrowing, and alveolar destruction. |
| How does COPD affect FEV1? | COPD causes an accelerated decline in FEV1, which otherwise normally declines slowly with age. |
| Which immune cells are involved in the inflammation associated with COPD? | The inflammation in COPD involves macrophages, neutrophils, and cytotoxic T cells. |
| How does smoking contribute to COPD beyond causing inflammation and mucus production? | Smoking promotes the infiltration of obstructing fibrous tissue and muscle in the airways and remodels blood vessels in the lungs, leading to pulmonary hypertension. |
| What is the partial pressure of oxygen in the atmosphere at sea level? | Since oxygen makes up approximately 20% of the atmosphere, its partial pressure is roughly 159 mmHg (760 x 0.20). |
| What are the approximate percentages of the main gases in the atmosphere? | Nitrogen makes up 78% of the atmosphere, oxygen is 21%, and carbon dioxide is 1%. |
| What does the oxygen electrode method measure? | It only measures the oxygen dissolved in the blood plasma, not the oxygen bound to hemoglobin in red blood cells. |
| What is a condition that results in dizziness and drowsiness when nitrogen is inhaled under high pressure, such as in deep-sea diving? | nitrogen narcosis |
| What is a condition where nitrogen bubbles form in the blood and block small vessels because a diver surfaced too fast or an airplane suddenly lost pressure? | decompression sickness |
| What are some common conditions treated with Hyperbaric Oxygen Therapy? | It is used to treat decompression sickness, gas gangrene, carbon monoxide poisoning, severe traumatic crush injuries, and diabetic sores. |
| Which areas of the brain control the contraction and relaxation of breathing muscles?--for voluntary and involuntary? | Contraction and relaxation are controlled by motor neurons from the cerebral cortex for voluntary breathing, and the medulla oblongata and pons for involuntary breathing. |
| Where do the motor neurons that innervate other breathing muscles arise? | They arise from the thoracolumbar region of the spinal cord. |
| What is the term for a loose aggregation of neurons in the ventrolateral region of the medulla that controls automatic breathing? | the rhythmicity center in the medulla oblongata |
| What is the suspected role of the Pre-Botzinger complex? | It is believed to generate the inspiratory rhythm, though it is not yet fully understood. |
| What is the dorsal respiratory group? | It is made up of inspiratory neurons (I neurons) that seem to stimulate neurons of the phrenic nerve. |
| What is the ventral respiratory group? | It is made up of neurons that seem to stimulate expiratory neurons (E neurons) that inhibit the phrenic nerve. |
| (bolded) How does the pons influence medulla activity? (2 centers) | The pons uses the apneustic center to promote inspiration and the pneumotaxic center to inhibit inspiration. |
| (bolded) Brainstem respiratory centers control breathing largely via the phrenic nerve from which spinal nuclei? (hint: cervical numbers) | C3-C6 (!) spinal nuclei |
| (bolded) Where are the central chemoreceptors located? Where are the peripheral chemoreceptors located? | central chemoreceptors are located in the medulla; peripheral are located in the aortic body and the carotid body. |
| (bolded) What kind of receptors monitor blood pressure in the aortic and carotid sinuses? | Baroreceptors monitor blood pressure, and should not be confused with the chemoreceptors in the aortic and carotid bodies. |
| (bolded) Which cranial nerve carries feedback from the aortic body to the medulla? | The vagus nerve. |
| (bolded) Which cranial nerve carries feedback from the carotid body to the medulla? | The glossopharyngeal nerve. |
| (bolded and highlighted in red) What is the direct stimulus for central chemoreceptors in the medulla? | The direct stimulus is an increase in H+ ions (decreased pH) in the brain fluids. |
| (bolded and highlighted in red) How do central chemoreceptors detect changes in blood CO2 if H+ cannot cross the blood-brain barrier? | CO2 diffuses from the blood across the barrier and forms carbonic acid and H+ in the brain interstitial fluid, which then stimulates the receptors. |
| (bolded and highlighted in red) Which chemoreceptors are responsible for the majority of increased ventilation? | Central chemoreceptors are responsible for 70-80% of increased ventilation, even though they take longer to respond than peripheral ones. |
| (bolded and highlighted in red) What directly stimulates peripheral chemoreceptors in the aortic and carotid bodies? | They are directly stimulated by a rise in H+ (a fall in blood pH) induced by increases in blood CO2. |
| Which chemical signals do the carotid bodies respond to? | The carotid bodies respond to all three chemical signals: rising PCO2, falling pH, and falling PO2. |
| Are central chemoreceptors affected by changes in blood pH? | No, central chemoreceptors are not affected by changes in blood pH because H+ cannot cross the blood-brain barrier. Though indirectly, through CO2 diffusion, they can be. |
| (bolded) Which fibers in the lungs are affected by capsaicin (like pepper spray) and produce rapid, shallow breathing? | unmyelinated C fibers |
| (bolded) Which receptors respond to smoke and particulates to stimulate coughing? | Irritant receptors in the wall of the larynx. |
| (bolded) Which receptors respond to excess fluid in the lung's interstitial tissue? | Rapidly adapting receptors. |
| What is the Hering-Breuer reflex? | It is a reflex stimulated by pulmonary stretch receptors that inhibits respiratory centers during inhalation to prevent inhaling too deeply and damaging lung tissue. |
| What effect does the hypocapnia from hyperventilation have on the brain? | Hypocapnia causes cerebral vasoconstriction, which results in inadequate brain perfusion and hypoxia that can produce dizziness. |
| How does hypocapnia affect blood pH and calcium levels? | It raises blood pH (respiratory alkalosis), which lowers plasma Ca2+ levels. |
| What triggers the gasp and jerk that ends a sleep apnea episode? | The temporary airway blockage causes PO2 to fall and PCO2 to rise, stimulating chemoreceptor reflexes that wake the person. |
| What 2 factors determine the total oxygen content of the blood? | Total oxygen content depends on both the PO2 and the hemoglobin concentration. |
| (good to know) What is the PO2 and percent saturation of systemic arterial blood? | Arterial blood has a PO2 of 100 mmHg and is 97% saturated. |
| (good to know) What is the PO2 and percent saturation of systemic venous blood at rest? | Venous blood has a PO2 of 40 mmHg and is 75% saturated. |
| (certain highlighted terms) What causes the sickling of red blood cells in sickle-cell anemia? | A single amino acid mutation creates hemoglobin S, which polymerizes into long fibers when deoxygenated, distorting the cell. |
| What happens to H+ when oxyhemoglobin is produced in the lungs? | It dissociates from hemoglobin and recombines with bicarbonate to form carbonic acid (H2CO3). |
| How are nonvolatile acids (like lactic, fatty, and ketone acids) buffered and regulated? by the lungs or by the kidneys? | They are buffered by bicarbonate and regulated by the kidneys via excretion, not by breathing. |
| According to the Henderson-Hasselbalch Equation, at what ratio of bicarbonate to CO2 is normal blood pH maintained? | A ratio of 20:1. |
| According to the Law of Mass Action, what happens during hypoventilation? (equation goes in what direction?) | Retained CO2 pushes the equation to the right, making extra H+ and causing respiratory acidosis. |
| According to the Law of Mass Action, what happens during hyperventilation? (equation goes in what direction?) | Lost CO2 pushes the equation to the left, using up H+ and causing respiratory alkalosis. |
| (emphasized) What two mechanisms control the increase in ventilation during exercise? | Neurogenic and humoral mechanisms. |
| (highlighted) How does sensory nerve activity from exercising muscles stimulate respiration? | Via spinal reflexes or brain stem respiratory centers. |
| (highlighted) Which part of the brain stimulates respiratory centers in anticipation of needing oxygen during exercise? | The cerebral cortex. |
| (highlighted) What do the proposed neurogenic mechanisms help explain regarding the timing of increased ventilation? | They help explain the immediate increase in ventilation at the beginning of exercise. |
| Why does rapid and deep breathing continue after exercise despite PO2, PCO2, and pH returning to resting ranges? | Due to humoral (chemical) factors. |
| What are two theories for why deep breathing continues after exercise when blood samples show normal values? | There may be regional PCO2 and pH differences at the chemoreceptors, or cyclic variations affecting chemoreceptors that blood samples miss |
| Are there consistent or significant changes in arterial blood gases and pH during the first several minutes of moderate and heavy exercise? | No, the body compensates very well. |
| Which arterial blood measurement actually decreases during more prolonged exercise? | PCO2. |
| (bolded in red) Does total O2 content and PO2 increase during exercise to deliver more oxygen to muscles? | No, oxygen delivery is increased even though total O2 content and PO2 do not increase. |
| What acid-base imbalance is initially caused by hyperventilating at high altitudes? | Respiratory alkalosis. |
| How does acute respiratory alkalosis affect the oxyhemoglobin dissociation curve? | It causes a left shift, meaning hemoglobin has a higher affinity for oxygen in the lungs. |
| What is Hypoxic Pulmonary Vasoconstriction (HPV) at high altitudes? | A systemic constriction of pulmonary arterioles in response to low oxygen. |
| What is a potential long-term risk of systemic Hypoxic Pulmonary Vasoconstriction? | Pulmonary hypertension and right ventricular hypertrophy. |
| What factor do tissues secrete to sprout new capillaries and shorten the oxygen diffusion distance? | Vascular Endothelial Growth Factor (VEGF). |
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