NR 507 WEEK 2 QUIZ QUESTIONS AND ANSWERS

NR 507 WEEK 2 QUIZ QUESTIONS AND ANSWERS Water movement between the intracellular fluid compartment and the extracellular compartment is primarily a function of osmotic forces. The movement of water between ICF and ECF compartments is primarily a function of osmotic forces. (Osmosis and other mechanisms of passive transport are discussed in Chapter 1.) How does the loss of chloride during vomiting cause metabolic alkalosis Loss of chloride causes retention of bicarbonate to maintain the anion balance. When acid loss is caused by vomiting with depletion of ECF and chloride (hypochloremic metabolic alkalosis), renal compensation is not very effective because the volume depletion and loss of electrolytes (Na+, K+, H+, Cl-) stimulate a paradoxical response by the kidneys. The kidneys increase sodium and bicarbonate reabsorption with excretion of hydrogen. Bicarbonate is reabsorbed to maintain an anionic balance because the ECF chloride concentration is decreased. What is a major determinant of the resting membrane potential necessary for transmission of nerve impulses? The ratio between intracellular K+ and extracellular potassium The ratio of K+ in the ICF to K+ in the ECF is the major determinant of the resting membrane potential, which is necessary for the transmission and conduction of nerve impulses, maintenance of normal cardiac rhythms, and skeletal and smooth muscle contraction. Why are infants susceptible to significant losses in total body water (TBW)? Because an infant’s kidneys are not mature enough to counter fluids losses Infants are particularly susceptible to significant changes in TBW because of their high metabolic rate and the accelerated turnover of body fluids caused by their greater body surface area in proportion to total body size. Loss of fluids from diarrhea can represent a significant proportion of body weight. Renal mechanisms that regulate fluid and electrolyte conservation may not be mature enough to counter the losses, so dehydration may develop rapidly At the arterial end of capillaries, fluid moves from the intravascular space into the interstitial space because the capillary hydrostatic pressure is higher than the capillary oncotic pressure. At the arterial end of capillaries, fluid moves from the intravascular space into the interstitial, because capillary hydrostatic pressure is higher than the capillary oncotic pressure. When thirst is experienced, how are osmoreceptors activated? By an increase in the osmotic pressure of the plasma Thirst is experienced when water loss equals 2% of an individual’s body weight or when there is an increase in osmolality. Dry mouth, hyperosmolality, and plasma volume depletion activate osmoreceptors (neurons located in the hypothalamus that are stimulated by increased osmolality). Physiologic pH is maintained around 7.4 because bicarbonate (HCO3) and carbonic acid (H2CO3) exist in a ratio of 20:1. The relationship between bicarbonate and carbonic acid is usually expressed as a ratio. When the pH is 7.40, this ratio is 20:1 (bicarbonate/carbonic acid). Pulmonary edema usually begins at a pulmonary capillary wedge pressure or left atrial pressure of _____ mm Hg. 20 Pulmonary edema usually begins to develop at a pulmonary capillary wedge pressure or left atrial pressure of 20 mm Hg _____ is a fulminant form of respiratory failure characterized by acute lung inflammation and diffuse alveolocapillary injury. Acute respiratory distress syndrome (ARDS) ARDS is a fulminant form of respiratory failure characterized by acute lung inflammation and diffuse alveolocapillary injury. Dyspnea is not a result of decreased blood flow to the medulla oblongata. There are no data to support the role of decreased blood flow to the medulla oblongata as being a cause of dyspnea. In tuberculosis, the body walls off the bacilli in a tubercle by stimulating apoptotic infected macrophages that activate cytotoxic T cells In defense, macrophages and lymphocytes release interferon, which inhibits the replication of the microorganism and stimulates more macrophages to attack the bacterium. Apoptotic infected macrophages also can activate cytotoxic T cells (CD8). Clinical manifestations of pulmonary hypertension include peripheral edema and jugular venous distention. Symptoms of fatigue, chest discomfort, tachypnea, and dyspnea on exertion, palpitations, and cough are common. Examination may reveal peripheral edema, jugular venous distention, a precordial heave, and accentuation of the pulmonary compartment of the second heart sound Clinical manifestations that include unexplained weight loss, dyspnea on exertion, use of accessory muscles, and tachypnea with prolonged expiration are indicative of emphysema. Individuals with emphysema usually have dyspnea on exertion that later progresses to marked dyspnea, even at rest (Table 33-3). Little coughing and very little sputum are produced. The individual often is thin, has tachypnea with prolonged expiration, and must use accessory muscles for ventilation. The anteroposterior diameter of the chest is increased (barrel chest), and the chest has a hyperresonant sound with percussion. In ARDS, alveoli and respiratory bronchioles fill with fluid as a result of the inactivation of surfactant and the impairment of type II alveolar cells. Lung inflammation and injury damages the alveolar epithelium and the vascular endothelium. Surfactant is inactivated, and its production by type II alveolar cells is impaired as alveoli and respiratory bronchioles fill with fluid or collapse. High altitudes may produce hypoxemia through decreased inspired oxygen. The first factor is the presence of adequate oxygen content of the inspired air. Oxygen content is lessened at high altitudes. Which inflammatory mediators are produced in asthma? Histamine, prostaglandins, and leukotrienes A large number of inflammatory mediators, such as histamine, prostaglandins, and leukotrienes are produced by asthma Which pleural abnormality involves a site of pleural rupture that act as a one-way valve, permitting air to enter on inspiration but preventing its escape by closing during expiration? Tension pneumothorax In tension pneumothorax, the site of pleural rupture acts as a one-way valve, permitting air to enter on inspiration but preventing its escape by closing up during expiration. As more and more air enters the pleural space, air pressure in the pneumothorax begins to exceed barometric pressure. The most successful treatment for chronic asthma begins with elimination of the causative agent. Chronic management of asthma begins with avoidance of allergens and other triggers. What is the primary cause of RDS of the newborn A surfactant deficiency RDS is caused primarily by surfactant deficiency and secondarily by a deficiency in alveolar surface area for gas exchange An accurate description of childhood asthma is that it is a(n) obstructive airway disease characterized by reversible airflow obstruction, bronchial hyperreactivity, and inflammation. Asthma is an obstructive airway disease characterized by reversible airflow obstruction, bronchial hyperreactivity, and inflammation. The release of fibroblast growth factors affects ARDS by causing pulmonary fibrosis. In the fibroproliferative phase, type II alveolar cells proliferate, and there is alveolar septal thickening and collagen deposition. Interstitial fibrosis can be evident as early as 10 days after the initial insult. Similarly, vascular changes may occur, including obliteration of the microcirculation and thickening of the walls of pulmonary arterioles and arteries, which can lead to chronic pulmonary hypertension in survivors. Which immunoglobulin is present in childhood asthma? IgE Included in the long list of asthma-associated genes are those that code for increased levels of immune and inflammatory mediators (e.g., IL-4, IgE, and leukotrienes), nitric oxide, and transmembrane proteins in the endoplasmic reticulum. Which of the following statements about the advances in the treatment of RDS of the newborn is incorrect? Administering oxygen to mothers during preterm labor increases their arterial oxygen before birth of the fetus. Administration of oxygen to the mother is not a valid treatment of RDS. Cystic fibrosis (CF) is caused by a(n) autosomal recessive inheritance. Cystic fibrosis is an autosomal recessive inherited disorder that is associated with defective epithelial ion transport. Which of the following types of croup is most common? Viral In 85% of cases, croup is caused by a virus, most commonly parainfluenza; however, other viruses such as influenza A or RSV also can cause croup. Chest wall compliance in infants is _____ in adults. higher than Chest wall compliance is high in infants, particularly premature infants. Chvostek sign and Trousseau sign indicate hypocalcemia. Which are indications of dehydration? Tachycardia and weight loss Marked water deficit is manifested by symptoms of dehydration: headache, thirst, dry skin and mucous membranes, elevated temperature, weight loss, and decreased or concentrated urine (with the exception of diabetes insipidus). Skin turgor may be normal or decreased. Symptoms of hypovolemia, including tachycardia, weak pulses, and postural hypotension, may be present. In hyperkalemia, cardiac rhythm changes are a direct result of cardiac cell hypopolarization. If extracellular potassium concentration increases without a significant change in intracellular potassium, the resting membrane potential becomes more positive (i.e., changes from –90 to –80 mV) and the cell membrane is hypopolarized (the inside of the cell becomes less negative or partially depolarized [increase excitability]). (Electrical properties of cells are discussed in Chapter 1.) Which of the following is a true statement? Hyperventilation causes hypocapnia. Hyperventilation is alveolar ventilation that exceeds metabolic demands. The lungs remove CO2 at a faster rate than it is produced by cellular metabolism, resulting in decreased PaCO2 or hypocapnia. Which enzyme is secreted by the juxtaglomerular cells of the kidney when circulating blood volume is reduced? Renin When circulating blood volume or blood pressure is reduced, renin, an enzyme secreted by the juxtaglomerular cells of the kidney, is released in response to sympathetic nerve stimulation and decreased perfusion of the renal vasculature. A(n) _____ is a circumscribed area of suppuration and destruction of lung parenchyma. Abscess Kussmaul respirations may be characterized as a respiratory pattern with a slightly increased ventilatory rate, large tidal volumes, and no expiratory pause.