Respiratory

Respiratory US Medical PG Question 1: A 37-year-old man is presented to the emergency department by paramedics after being involved in a serious 3-car collision on an interstate highway while he was driving his motorcycle. On physical examination, he is responsive only to painful stimuli and his pupils are not reactive to light. His upper extremities are involuntarily flexed with hands clenched into fists. The vital signs include temperature 36.1°C (97.0°F), blood pressure 80/60 mm Hg, and pulse 102/min. A non-contrast computed tomography (CT) scan of the head shows a massive intracerebral hemorrhage with a midline shift. Arterial blood gas (ABG) analysis shows partial pressure of carbon dioxide in arterial blood (PaCO2) of 68 mm Hg, and the patient is put on mechanical ventilation. His condition continues to decline while in the emergency department and it is suspected that this patient is brain dead. Which of the following results can be used to confirm brain death and legally remove this patient from the ventilator?

• A. Electrocardiogram
• B. Apnea test (Correct Answer)
• C. Lumbar puncture and CSF culture
• D. Electromyography with nerve conduction studies
• E. CT scan

Respiratory Explanation: ***Correct: Apnea test*** - The **apnea test** is a **mandatory component** of brain death determination according to American Academy of Neurology (AAN) guidelines - It directly confirms the **irreversible absence of brainstem function** by demonstrating no respiratory drive despite adequate stimulus (PaCO2 ≥60 mm Hg or 20 mm Hg rise from baseline) - This patient already has a PaCO2 of 68 mm Hg, making the apnea test particularly relevant for confirmation - Brain death requires both **clinical examination** (absent brainstem reflexes, coma) and a **positive apnea test** to legally declare death and discontinue mechanical ventilation - The apnea test is performed by disconnecting the ventilator, providing supplemental oxygen, and observing for any respiratory effort while PaCO2 rises to adequate levels *Incorrect: CT scan* - While a **CT scan showing massive intracerebral hemorrhage with midline shift** provides anatomical evidence of severe, irreversible structural brain damage, it is **NOT sufficient to confirm brain death** - CT imaging is used to establish the **etiology** and rule out reversible causes, but does not directly test brainstem function - Brain death is a **clinical and functional diagnosis**, not purely an anatomical one—imaging alone cannot confirm cessation of all brain function - A patient can have devastating structural damage on CT but still retain some brainstem reflexes *Incorrect: Electrocardiogram* - An **electrocardiogram (ECG)** measures cardiac electrical activity and provides no information about brain or brainstem function - Cardiac activity commonly persists after brain death due to the heart's intrinsic automaticity - ECG findings are irrelevant to brain death determination *Incorrect: Lumbar puncture and CSF culture* - **Lumbar puncture and CSF culture** are used to diagnose CNS infections (meningitis, encephalitis) or inflammatory conditions - These tests are **completely irrelevant** for brain death diagnosis, which is based on irreversible cessation of all brain function, not infection - In this trauma case with known intracerebral hemorrhage, LP would be contraindicated due to increased intracranial pressure and risk of herniation *Incorrect: Electromyography with nerve conduction studies* - **EMG and nerve conduction studies** assess peripheral nerve and muscle function, used for diagnosing neuromuscular disorders - These tests provide no information about brain or brainstem function - They are not part of brain death determination protocols

Respiratory US Medical PG Question 2: A 55-year-old man is brought to the emergency department by ambulance from a long term nursing facility complaining of severe shortness of breath. He suffers from amyotrophic lateral sclerosis and lives at the nursing home full time. He has had the disease for 2 years and it has been getting harder to breath over the last month. He is placed on a rebreather mask and responds to questions while gasping for air. He denies cough or any other upper respiratory symptoms and denies a history of cardiovascular or respiratory disease. The blood pressure is 132/70 mm Hg, the heart rate is 98/min, the respiratory rate is 40/min, and the temperature is 37.6°C (99.7°F). During the physical exam, he begs to be placed in a sitting position. After he is repositioned his breathing improves a great deal. On physical examination, his respiratory movements are shallow and labored with paradoxical inward movement of his abdomen during inspiration. Auscultation of the chest reveals a lack of breath sounds in the lower lung bilaterally. At present, which of the following muscles is most important for inspiration in the patient?

• A. Muscles of anterior abdominal wall
• B. Sternocleidomastoid muscles (Correct Answer)
• C. Internal intercostal muscles
• D. Trapezius muscle
• E. External intercostal muscles

Respiratory Explanation: ***Sternocleidomastoid muscles*** - In advanced **amyotrophic lateral sclerosis (ALS)**, progressive motor neuron degeneration affects both the diaphragm and intercostal muscles - The **paradoxical inward movement of the abdomen** during inspiration indicates severe diaphragmatic weakness or paralysis - The **shallow respiratory movements** and **severe respiratory distress** (respiratory rate 40/min) suggest that both primary inspiratory muscle groups (diaphragm and external intercostals) are significantly compromised - At this stage, **accessory muscles of inspiration**, particularly the **sternocleidomastoid muscles**, become critically important for maintaining ventilation by elevating the sternum and upper ribs - The dramatic improvement when sitting upright (orthopnea relief) supports accessory muscle recruitment, as this position optimizes sternocleidomastoid mechanical advantage - **Clinical pearl:** In neuromuscular respiratory failure, neck muscle recruitment (visible SCM contraction) is a key sign of impending respiratory failure requiring ventilatory support *External intercostal muscles* - The **external intercostal muscles** are normally primary muscles of inspiration that elevate the ribs - However, in advanced ALS with **2 years of progressive disease** and worsening dyspnea over the past month, these muscles would also be significantly weakened by the neurodegenerative process - The **lack of breath sounds in the lower lungs bilaterally** suggests poor chest wall expansion, indicating compromised intercostal function - While they continue to contribute, they are insufficient to maintain adequate ventilation alone at this stage of disease *Internal intercostal muscles* - The **internal intercostal muscles** function primarily in **forced expiration** by depressing the ribs - They do not play a significant role in inspiration *Muscles of anterior abdominal wall* - The **anterior abdominal wall muscles** (rectus abdominis, external/internal obliques, transversus abdominis) are **expiratory muscles** used in forced expiration and coughing - The **paradoxical inward movement** of the abdomen during inspiration is a passive phenomenon resulting from diaphragmatic weakness—the negative intrathoracic pressure pulls the weakened diaphragm upward, which in turn draws the abdominal wall inward - These muscles are not contributing to inspiration in this patient *Trapezius muscle* - The **trapezius** primarily functions in scapular movement and neck stabilization - While it provides some mechanical stability for the shoulder girdle during accessory muscle breathing, it is not directly involved in rib cage elevation - It plays a minor supportive role compared to the sternocleidomastoid in respiratory distress

Respiratory US Medical PG Question 3: Which of the following physiologic changes decreases pulmonary vascular resistance (PVR)?

• A. Inhaling the inspiratory reserve volume (IRV)
• B. Exhaling the entire vital capacity (VC)
• C. Exhaling the expiratory reserve volume (ERV)
• D. Breath holding maneuver at functional residual capacity (FRC)
• E. Inhaling the entire vital capacity (VC) (Correct Answer)

Respiratory Explanation: ***Inhaling the entire vital capacity (VC)*** - As lung volume increases from FRC to TLC (which includes inhaling the entire VC), alveolar vessels are **stretched open**, and extra-alveolar vessels are **pulled open** by the increased radial traction, leading to a decrease in PVR. - This **maximizes the cross-sectional area** of the pulmonary vascular bed, lowering resistance. *Inhaling the inspiratory reserve volume (IRV)* - While inhaling IRV increases lung volume, it's not the maximal inspiration of the entire VC where **PVR is typically at its lowest**. - PVR continues to decrease as lung volume approaches total lung capacity (TLC). *Exhaling the entire vital capacity (VC)* - Exhaling the entire vital capacity leads to very low lung volumes, where PVR significantly **increases**. - At low lung volumes, **alveolar vessels become compressed** and extra-alveolar vessels **narrow**, increasing resistance. *Exhaling the expiratory reserve volume (ERV)* - Exhaling the ERV results in a lung volume below FRC, which causes a **marked increase in PVR**. - This is due to the **compression of alveolar vessels** and decreased radial traction on extra-alveolar vessels. *Breath holding maneuver at functional residual capacity (FRC)* - At FRC, the PVR is at an **intermediate level**, not its lowest. - This is the point where the opposing forces affecting alveolar and extra-alveolar vessels are somewhat balanced, but not optimized for minimal resistance.

Respiratory US Medical PG Question 4: A 27-year-old woman is admitted to the emergency room with dyspnea which began after swimming and progressed gradually over the last 3 days. She denies cough, chest pain, or other respiratory symptoms. She reports that for the past 4 months, she has had several dyspneic episodes that occurred after the exercising and progressed at rest, but none of these were as long as the current one. Also, she notes that her tongue becomes ‘wadded’ when she speaks and she tires very quickly during the day. The patient’s vital signs are as follows: blood pressure 125/60 mm Hg, heart rate 92/min, respiratory rate 34/min, and body temperature 36.2℃ (97.2℉). Blood saturation on room air is initially 92% but falls to 90% as she speaks up. On physical examination, the patient is slightly lethargic. Her breathing is rapid and shallow. Lung auscultation, as well as cardiac, and abdominal examinations show no remarkable findings. Neurological examination reveals slight bilateral ptosis increased by repetitive blinking, and easy fatigability of muscles on repeated movement worse on the face and distal muscles of the upper and lower extremities. Which arterial blood gas parameters would you expect to see in this patient?

• A. PaCO2 = 51 mm Hg, PaO2 = 58 mm Hg (Correct Answer)
• B. PaCO2 = 37 mm Hg, PaO2 = 46 mm Hg
• C. PaCO2 = 34 mm Hg, PaO2 = 61 mm Hg
• D. PaCO2 = 31 mm Hg, PaO2 = 67 mm Hg
• E. PaCO2 = 43 mm Hg, PaO2 = 55 mm Hg

Respiratory Explanation: ***PaCO2 = 51 mm Hg, PaO2 = 58 mm Hg*** - The patient presents with symptoms highly suggestive of a **myasthenic crisis**, including progressive dyspnea, worsened by exertion (speaking), ptosis, and generalized muscle fatigability. These symptoms indicate **respiratory muscle weakness**, leading to hypoventilation. - **Hypoventilation** results in **hypercapnia (elevated PaCO2)** and **hypoxemia (decreased PaO2)**. An elevated PaCO2 of 51 mm Hg and decreased PaO2 of 58 mm Hg are consistent with this presentation, reflecting inadequate ventilation. *PaCO2 = 37 mm Hg, PaO2= 46 mm Hg* - A PaCO2 of 37 mm Hg is within the normal range or slightly low, suggesting that the patient is not significantly hypercapnic, which contradicts the clinical picture of **respiratory muscle weakness and hypoventilation**. - While PaO2 is significantly low at 46 mm Hg (indicating hypoxemia), the normal/low PaCO2 would point to a primary **oxygenation defect** (e.g., V/Q mismatch) rather than a ventilatory failure. *PaCO2 = 34 mm Hg, PaO2 = 61 mm Hg* - A PaCO2 of 34 mm Hg indicates **hypocapnia**, which is more consistent with hyperventilation rather than the hypoventilation expected from **respiratory muscle weakness** in myasthenic crisis. - While PaO2 of 61 mm Hg indicates hypoxemia, the accompanying hypocapnia suggests a primary **respiratory drive issue** or conditions causing hyperventilation, not ventilatory failure due to muscle weakness. *PaCO2 = 31 mm Hg, PaO2 = 67 mm Hg* - A PaCO2 of 31 mm Hg reflects significant **hypocapnia**, indicating that the patient is **hyperventilating**. This is contrary to what would be expected in a myasthenic crisis where respiratory muscle weakness leads to hypoventilation. - While PaO2 is decreased, suggesting some respiratory compromise, the ventilatory pattern (hypocapnia) does not match the clinical syndrome of **respiratory muscle fatigue**. *PaCO2 = 43 mm Hg, PaO2 = 55 mm Hg* - A PaCO2 of 43 mm Hg is within the **normal reference range**, which would mean there is no CO2 retention and thus no obvious **alveolar hypoventilation** from respiratory muscle weakness. - While PaO2 of 55 mm Hg indicates hypoxemia, the normal PaCO2 suggests that the hypoxemia is due to other causes like a **V/Q mismatch** rather than inadequate overall ventilation.

Respiratory US Medical PG Question 5: A 24-year-old woman presents to the emergency department after she was found agitated and screaming for help in the middle of the street. She says she also has dizziness and tingling in the lips and hands. Her past medical history is relevant for general anxiety disorder, managed medically with paroxetine. At admission, her pulse is 125/min, respiratory rate is 25/min, and body temperature is 36.5°C (97.7°F). Physical examination is unremarkable. An arterial blood gas sample is taken. Which of the following results would you most likely expect to see in this patient?

• A. pH: increased, HCO3-: increased, Pco2: increased
• B. pH: decreased, HCO3-: decreased, Pco2: decreased
• C. pH: decreased, HCO3-: increased, Pco2: increased
• D. pH: increased, HCO3-: decreased, Pco2: decreased (Correct Answer)
• E. pH: normal, HCO3-: increased, Pco2: increased

Respiratory Explanation: ***pH: increased, HCO3-: decreased, Pco2: decreased*** - The patient's presentation with **agitation**, **dizziness**, **paresthesias** (tingling in lips and hands), and **tachypnea** (respiratory rate 25/min) is highly suggestive of **hyperventilation** due to an anxiety attack. - **Hyperventilation** leads to excessive **CO2 expulsion**, causing a decrease in Pco2, which results in respiratory alkalosis (increased pH) and a compensatory decrease in HCO3-. *pH: increased, HCO3-: increased, Pco2: increased* - An **increased pH** coupled with **increased HCO3-** and **increased Pco2** would suggest a **metabolic alkalosis with respiratory compensation**, which is not consistent with the patient's acute hyperventilation. - While pH is increased, the other values contradict the primary respiratory cause suggested by the symptoms. *pH: decreased, HCO3-: decreased, Pco2: decreased* - This profile describes **metabolic acidosis with respiratory compensation**, which would typically present with **Kussmaul breathing** and other signs of acidosis, not acute hyperventilation and agitation. - Symptoms such as dizziness and tingling are associated with alkalosis, not acidosis. *pH: decreased, HCO3-: increased, Pco2: increased* - This pattern is characteristic of **respiratory acidosis with metabolic compensation**, often seen in conditions like **COPD exacerbation** or **opioid overdose** with hypoventilation. - The patient's rapid breathing and clinical picture are not consistent with respiratory acidosis. *pH: normal, HCO3-: increased, Pco2: increased* - A **normal pH** with **increased HCO3-** and **increased Pco2** would indicate a **compensated metabolic alkalosis**. - Her acute symptoms point to an uncompensated or acutely compensated respiratory disorder, not a compensated metabolic issue.

Respiratory US Medical PG Question 6: A 32-year-old woman comes to the physician for a screening health examination that is required for scuba diving certification. The physician asks her to perform a breathing technique: following deep inspiration, she is instructed to forcefully exhale against a closed airway and contract her abdominal muscles while different cardiovascular parameters are evaluated. Which of the following effects is most likely after 10 seconds in this position?

• A. Decreased intra-abdominal pressure
• B. Decreased left ventricular stroke volume (Correct Answer)
• C. Decreased pulse rate
• D. Decreased systemic vascular resistance
• E. Increased venous return to left atrium

Respiratory Explanation: ***Decreased left ventricular stroke volume*** - After 10 seconds of performing the **Valsalva maneuver**, the increased intrathoracic pressure significantly reduces **venous return** to the heart. - Reduced venous return leads to decreased **ventricular filling** (preload), which in turn diminishes **left ventricular stroke volume** and cardiac output. *Decreased intra-abdominal pressure* - The instruction to "contract her abdominal muscles" during forceful exhalation against a closed airway (Valsalva maneuver) directly leads to an **increase** in **intra-abdominal pressure**, not a decrease. - This increase in intra-abdominal pressure further impedes venous return from the lower extremities to the heart. *Decreased pulse rate* - In the initial phase of the Valsalva maneuver (first 5-10 seconds), the decrease in cardiac output triggers a **reflex tachycardia** to maintain blood pressure, leading to an **increased pulse rate**. - A decrease in pulse rate (bradycardia) is more characteristic of the release phase, not during the sustained strain. *Decreased systemic vascular resistance* - During the Valsalva maneuver, the body attempts to compensate for the drop in cardiac output and blood pressure by increasing **sympathetic tone**, which causes **vasoconstriction** and thus **increases systemic vascular resistance**. - A decrease in systemic vascular resistance would further drop blood pressure and is not the physiological response during this phase. *Increased venous return to left atrium* - The Valsalva maneuver dramatically **reduces venous return** to both the right and left atria due to the high intrathoracic pressure compressing the great veins. - This decreased venous return is the primary mechanism leading to the subsequent fall in cardiac output during the maneuver.

Respiratory US Medical PG Question 7: A student health coordinator plans on leading a campus-wide HIV screening program that will be free for the entire undergraduate student body. The goal is to capture as many correct HIV diagnoses as possible with the fewest false positives. The coordinator consults with the hospital to see which tests are available to use for this program. Test A has a sensitivity of 0.92 and a specificity of 0.99. Test B has a sensitivity of 0.95 and a specificity of 0.96. Test C has a sensitivity of 0.98 and a specificity of 0.93. Which of the following testing schemes should the coordinator pursue?

• A. Test A on the entire student body followed by Test B on those who are positive
• B. Test A on the entire student body followed by Test C on those who are positive
• C. Test C on the entire student body followed by Test B on those who are positive
• D. Test C on the entire student body followed by Test A on those who are positive (Correct Answer)
• E. Test B on the entire student body followed by Test A on those who are positive

Respiratory Explanation: ***Test C on the entire student body followed by Test A on those who are positive*** - To "capture as many correct HIV diagnoses as possible" (maximize true positives), the initial screening test should have the **highest sensitivity**. Test C has the highest sensitivity (0.98). - To "capture as few false positives as possible" (maximize true negatives and confirm diagnoses), the confirmatory test should have the **highest specificity**. Test A has the highest specificity (0.99). *Test A on the entire student body followed by Test B on those who are positive* - Starting with Test A (sensitivity 0.92) would miss more true positive cases than starting with Test C (sensitivity 0.98), failing the goal of **capturing as many cases as possible**. - Following with Test B (specificity 0.96) would result in more false positives than following with Test A (specificity 0.99). *Test A on the entire student body followed by Test C on those who are positive* - This scheme would miss many true positive cases initially due to Test A's lower sensitivity compared to Test C. - Following with Test C would introduce more false positives than necessary, as it has a lower specificity (0.93) than Test A (0.99). *Test C on the entire student body followed by Test B on those who are positive* - While Test C is a good initial screen for its high sensitivity, following it with Test B (specificity 0.96) is less optimal than Test A (specificity 0.99) for minimizing false positives in the confirmation step. - This combination would therefore yield more false positives in the confirmatory stage than using Test A. *Test B on the entire student body followed by Test A on those who are positive* - Test B has a sensitivity of 0.95, which is lower than Test C's sensitivity of 0.98, meaning it would miss more true positive cases at the initial screening stage. - While Test A provides excellent specificity for confirmation, the initial screening step is suboptimal for the goal of capturing as many diagnoses as possible.

Respiratory US Medical PG Question 8: During heavy exercise, what is the primary mechanism for maintaining arterial pH despite increased lactic acid production?

• A. Increased bicarbonate reabsorption
• B. Phosphate buffering
• C. Increased hydrogen secretion
• D. Hyperventilation (Correct Answer)

Respiratory Explanation: ***Hyperventilation*** - **Hyperventilation** during heavy exercise increases the expulsion of **carbon dioxide (CO2)**, shifting the **bicarbonate buffer system** equilibrium to the left. - This reduction in **CO2** effectively removes **hydrogen ions (H+)**, thereby helping to maintain **arterial pH** despite rising **lactic acid** levels. *Increased bicarbonate reabsorption* - While the kidneys adapt by increasing **bicarbonate reabsorption** to compensate for acidosis, this is a **slower renal mechanism** for pH regulation, taking hours to days, rather than an immediate response during acute exercise. - The rapid pH regulation during exercise primarily relies on respiratory and chemical buffer systems, not renal function. *Phosphate buffering* - The **phosphate buffer system** is indeed important for intracellular and renal tubular fluid buffering. - However, its buffering capacity in the extracellular fluid and plasma is relatively limited compared to the **bicarbonate system** due to its lower concentration. *Increased hydrogen secretion* - **Increased hydrogen secretion** by the renal tubules is a long-term mechanism for compensating for acidosis, which helps excrete excess **acid** and regenerate **bicarbonate**. - This is a slow, renal regulatory process and not the primary rapid mechanism for maintaining pH during the immediate demands of heavy exercise.

Respiratory US Medical PG Question 9: A 35-year-old man presents to pulmonary function clinic for preoperative evaluation for a right pneumonectomy. His arterial blood gas at room air is as follows: pH: 7.34 PaCO2: 68 mmHg PaO2: 56 mmHg Base excess: +1 O2 saturation: 89% What underlying condition most likely explains these findings?

• A. Cystic fibrosis
• B. Bronchiectasis
• C. Chronic obstructive pulmonary disease (Correct Answer)
• D. Obesity
• E. Acute respiratory distress syndrome

Respiratory Explanation: ***Chronic obstructive pulmonary disease*** - This patient exhibits **compensated respiratory acidosis** (low pH, high PaCO2, slightly elevated base excess) and **hypoxemia** (low PaO2), which are characteristic findings in chronic obstructive pulmonary disease (COPD) with underlying respiratory failure. - The history of a planned **pneumonectomy** also suggests a significant pre-existing lung pathology often seen in patients with severe COPD. *Cystic fibrosis* - While cystic fibrosis can lead to chronic lung disease, it typically presents at a younger age and is associated with a history of recurrent infections and exocrine gland dysfunction. - While it can manifest similarly in ABG, the age and the planned pneumonectomy make COPD a more likely primary cause in this context. *Bronchiectasis* - Bronchiectasis involves permanent dilation of the bronchi, often leading to chronic cough, sputum production, and recurrent infections. - While it can cause respiratory compromise, the ABG findings are more classically associated with the widespread air trapping and V/Q mismatch seen in COPD. *Obesity* - Severe obesity can lead to **obesity hypoventilation syndrome**, presenting with hypercapnia and hypoxemia. - However, the patient's age and the context of a planned pneumonectomy make an underlying primary lung disease like COPD a more focused explanation for the ABG pattern. *Acute respiratory distress syndrome* - Acute respiratory distress syndrome (ARDS) is an **acute** and severe form of respiratory failure characterized by severe hypoxemia and bilateral opacities on chest imaging. - The ABG findings in ARDS typically show **severe hypoxemia** with **respiratory alkalosis** early on, evolving to acidosis, and it is an acute process, not a chronic pre-existing condition suitable for elective surgery.

Respiratory US Medical PG Question 10: A 56-year-old male comes to the physician because of a 2-month history of excessive sleepiness. He reports that he has been sleeping for an average of 10 to 12 hours at night and needs to take multiple naps during the day. Six months ago, he was diagnosed with small cell lung carcinoma and underwent prophylactic cranial irradiation. This patient's symptoms are most likely caused by damage to which of the following structures?

• A. Subthalamic nucleus
• B. Ventromedial nucleus
• C. Suprachiasmatic nucleus (Correct Answer)
• D. Preoptic nucleus
• E. Supraoptic nucleus

Respiratory Explanation: ***Suprachiasmatic nucleus*** - The **suprachiasmatic nucleus (SCN)** is the primary pacemaker of the **circadian rhythm**, regulating the sleep-wake cycle. Damage to this structure, as from prophylactic cranial irradiation, can lead to disruptions in sleep patterns, such as **excessive daytime sleepiness** and prolonged nocturnal sleep. - The SCN receives input from the **retino-hypothalamic tract** and projects to other hypothalamic nuclei to control the secretion of hormones like **melatonin**, which further regulates sleep. *Subthalamic nucleus* - The **subthalamic nucleus** is a component of the basal ganglia motor circuit and is primarily involved in **motor control**. - Dysfunction of this nucleus is typically associated with **movement disorders** like hemiballismus, not sleep disturbances. *Ventromedial nucleus* - The **ventromedial nucleus of the hypothalamus** is primarily involved in regulating **satiety** and metabolism. - Damage to this nucleus is more likely to cause symptoms like **hyperphagia** and obesity, not excessive sleepiness. *Preoptic nucleus* - The **preoptic nucleus** is involved in **thermoregulation** and aspects of sleep regulation, particularly the initiation of NREM sleep. - While it has a role in sleep, the **suprachiasmatic nucleus** is the primary driver of the overall circadian rhythm and sustained excessive sleepiness observed here. *Supraoptic nucleus* - The **supraoptic nucleus** is a neurosecretory nucleus in the hypothalamus responsible for producing **vasopressin (ADH)** and **oxytocin**. - Damage to this nucleus would primarily result in **diabetes insipidus** due to ADH deficiency, not disturbances in the sleep-wake cycle.

Respiratory Flashcard 1 of 10

Question: In response to high altitude, there is a chronic _____ in ventilation

Answer: increase

Respiratory Flashcard 2 of 10

Question: Peripheral chemoreceptors are stimulated by increased _____

Answer: Paco2

Respiratory Flashcard 3 of 10

Question: The _____ zone of the lung is responsible for warming, humidifying, and filtering the air

Answer: conducting

Respiratory Flashcard 4 of 10

Question: _____ receptors are mechanoreceptors located in the smooth muscle of the airways

Answer: Lung stretch

Respiratory Flashcard 5 of 10

Question: The dorsal respiratory group receives sensory input from lung stretch receptors via the _____ nerve

Answer: vagus (CN X)

Respiratory Flashcard 6 of 10

Question: The dorsal respiratory group sends its motor output to the diaphragm via the _____ nerve

Answer: phrenic

Respiratory Flashcard 7 of 10

Question: How does hyperventilation affect ICP?

Answer: low PCO2 leads to less cerebral blood flow, reducing ICP

Respiratory Flashcard 8 of 10

Question: In what situations is hyperventilation therapuetic?

Answer: increased ICP

Respiratory Flashcard 9 of 10

Question: What type of cytoskeletal element is most associated with flagella?

Answer: microtubules

Respiratory Flashcard 10 of 10

Question: What type of cytoskeletal element is most associated with cilia?

Answer: microtubules