Other than the absorption/infusion rate, which best explains why enteral potassium administration is safer than parenteral potassium administration?

Correct Answer: B

Rationale: The correct answer is B) Feed-forward sensing of changes in mesenteric potassium concentration increases urinary potassium excretion. Enteral potassium administration is safer than parenteral administration due to the body's ability to sense and regulate potassium levels in the gastrointestinal (GI) tract. When potassium is administered enterally, the gut sensors detect the presence of potassium, triggering mechanisms that increase urinary excretion of potassium to maintain balance. This feed-forward mechanism helps prevent rapid spikes in potassium levels, reducing the risk of hyperkalemia. Option A is incorrect because the bioavailability of potassium is not significantly lower with enteral administration. In fact, enteral administration allows for efficient absorption of potassium. Option C is incorrect because while potassium chloride elixir may cause diarrhea, it does not necessarily reduce potassium absorption significantly. Diarrhea may lead to some loss of potassium but is not the primary reason for the safety of enteral administration. Option D is incorrect as wax matrix tablets sequestering potassium release throughout the GI tract does not explain why enteral administration is safer than parenteral administration based on the body's natural mechanisms for potassium regulation. In an educational context, understanding the differences between enteral and parenteral administration of potassium is crucial for healthcare professionals involved in managing patients with electrolyte imbalances. Knowing the physiological mechanisms that make enteral administration safer can help in making informed decisions regarding the route of administration based on the patient's condition and needs.

Correct Answer: C

Rationale: The correct answer is C) cells because approximately 60% of the body's water is located within cells, making it the largest compartment for body water storage. This intracellular water plays a crucial role in various cellular functions, such as nutrient transport, waste removal, and overall cell metabolism. Option A) plasma refers to the liquid component of blood and contains about 8% of the body's water. While it is essential for transporting nutrients and waste products, it is not where the majority of body water is located. Option B) interstitial fluid surrounds cells and makes up about 26% of the body's water. It serves as a medium for exchanging nutrients and waste products between cells and blood vessels but is not the primary location for body water. Option D) lumens of organs open to the outside, like the gastrointestinal tract, respiratory tract, and urinary system, contain a small percentage of body water involved in various physiological processes but do not account for the majority of body water as indicated in the question. Understanding the distribution of body water is essential in the field of nutrition and fluid balance as it impacts overall hydration, electrolyte balance, and cellular function. Educating individuals on the importance of maintaining adequate hydration levels and understanding the body's water compartments can help promote optimal health and well-being.

Correct Answer: D

Rationale: In the context of the hormone that regulates water reabsorption by the kidneys, the correct answer is D) only increases water permeability in certain portions of the kidney tubules. This hormone is vasopressin, also known as antidiuretic hormone (ADH). Vasopressin acts specifically on the collecting ducts of the nephron in the kidneys. It does so by inserting aquaporin-2 water channels into the apical membrane of the collecting duct cells, allowing for water reabsorption in response to dehydration or high blood osmolality. Option A is incorrect because vasopressin actually increases water permeability, not decreases it, and it acts selectively rather than throughout all kidney tubules. Option C is incorrect because vasopressin affects water permeability beyond certain portions of the kidney tubules. Option B is incorrect because vasopressin does not increase water permeability throughout all kidney tubules but rather in specific areas where it is needed to maintain fluid balance in the body. Understanding the role of vasopressin in regulating water reabsorption is crucial in the study of fluid balance and kidney function. This knowledge is essential in comprehending conditions such as diabetes insipidus or syndrome of inappropriate antidiuretic hormone secretion (SIADH), where the regulation of vasopressin is disrupted, leading to abnormal water balance in the body. By grasping the specific action of vasopressin in the kidneys, healthcare professionals can better manage and treat patients with such conditions effectively.

Correct Answer: B

Rationale: The correct answer is B) inhibition of vasopressin secretion. When venous return increases, it signifies that there is sufficient blood volume returning to the heart. This activates stretch receptors in the atria of the heart, which then signal the body to inhibit the secretion of vasopressin. Vasopressin is an antidiuretic hormone that plays a key role in regulating water retention by the kidneys. In this scenario, inhibiting vasopressin secretion helps to prevent excess water retention and maintain fluid balance. Option A) secretion of vasopressin is incorrect because increased venous return actually leads to the inhibition, not the secretion, of vasopressin. Option C) increased glomerular filtration is unrelated to the activation of stretch receptors in the atria caused by increased venous return. Option D) decreased urine production is also incorrect since inhibiting vasopressin secretion would actually promote urine production by allowing more water to be excreted by the kidneys. Understanding the relationship between venous return, stretch receptors, and vasopressin secretion is crucial in comprehending the body's mechanisms for maintaining fluid balance. This knowledge is fundamental in the field of nutrition and overall health, as proper fluid balance is essential for various physiological functions. By grasping these concepts, individuals can make informed decisions about their hydration levels and dietary choices to support optimal health and well-being.

Correct Answer: D

Rationale: The correct answer is D because the Renin-Angiotensin System (RAS) pathway is activated by a combination of low blood pressure in arterioles in the nephron and a decrease in fluid flow through the distal tubule. This activation is crucial for maintaining blood pressure and fluid balance in the body. Option A is incorrect because RAS is not only activated by low blood pressure in nephron arterioles, but also requires a decrease in fluid flow through the distal tubule. Option B is incorrect as it simplifies the activation stimuli by focusing only on the distal tubule, neglecting the role of low blood pressure in arterioles in the nephron. Option C is also incorrect because high blood pressure in the renal artery does not stimulate the RAS pathway. Educationally, understanding the stimuli for RAS activation is essential in comprehending the intricate regulatory mechanisms of blood pressure and fluid balance in the body. By grasping the specific triggers like low blood pressure in arterioles and reduced flow in the distal tubule, students can appreciate the interconnected physiological processes that maintain homeostasis. This knowledge is foundational in fields like medicine, nursing, and physiology where a deep understanding of the renal system is critical.