the most common positive ion in intracellular fluid is

ATI RN

ATI Fluid and Electrolytes

1. Which positive ion is most prevalent in intracellular fluid?

A. Calcium
B. Potassium
C. Sodium
D. Magnesium

Correct answer: B

Rationale: The correct answer is Potassium (K+). Potassium is the predominant cation found within cells, making it the most prevalent positive ion in intracellular fluid. Calcium, sodium, and magnesium are also essential ions in the body, but they are not as abundant in intracellular fluid. Calcium is vital for bone health and muscle function, sodium helps in maintaining fluid balance and nerve function, and magnesium is involved in numerous biochemical reactions.

2. A patient who is being treated for pneumonia starts complaining of sudden shortness of breath. An arterial blood gas (ABG) is drawn. The ABG has the following values: pH 7.21, PaCO2 64 mm Hg, HCO3 = 24 mm Hg. What does the ABG reflect?

A. Respiratory acidosis
B. Metabolic alkalosis
C. Respiratory alkalosis
D. Metabolic acidosis

Correct answer: A

Rationale:

3. The nurse is assessing the patient for the presence of a Chvostek's sign. What electrolyte imbalance does a positive Chvostek's sign indicate?

A. Hypermagnesemia
B. Hypomagnesemia
C. Hypocalcemia
D. Hyperkalemia

Correct answer: C

Rationale: Chvostek's sign is characterized by a brief contraction of the upper lip, nose, or side of the face and is indicative of hypocalcemia, making choice C the correct answer. Hypomagnesemia (choice B) is associated with Trousseau's sign, not Chvostek's sign. Hypermagnesemia (choice A) is not related to Chvostek's sign. Hyperkalemia (choice D) is not typically associated with Chvostek's sign; instead, it may present with muscle weakness and cardiac arrhythmias.

4. A 73-year-old man who slipped on a small carpet in his home and fell on his hip is alert and oriented; PERRLA (pupils equally round and reactive to light and accommodation) is intact, and he has come by ambulance to the emergency department (ED). Heart rate elevated, he is anxious and thirsty. A Foley catheter is in place and 40mL of urine is present. The nurse's most likely explanation for the urine output is:

A. The man urinated prior to his arrival in the ED and will probably not need to have the Foley catheter kept in place.
B. The man has a brain injury, lacks ADH, and needs vasopressin.
C. The man is in heart failure and is releasing atrial natriuretic peptide, which results in decreased urine output.
D. He is having a sympathetic reaction, which has stimulated the renin-angiotensin-aldosterone system that results in diminished urine output.

Correct answer: D

Rationale: Renin is released by the juxtaglomerular cells of the kidneys in response to decreased renal perfusion. Angiotensin-converting enzyme converts angiotensin I to angiotensin II. Angiotensin II, with its vasoconstrictor properties, increases arterial perfusion pressure and stimulates thirst. As the sympathetic nervous system is stimulated, aldosterone is released in response to an increased release of renin, which decreases urine production. Based on the nursing assessment and mechanism of injury, this is the most likely cause of the lower urine output. Choices A, B, and C are incorrect because there is no indication of urination prior to arrival, brain injury, lack of ADH, or heart failure present in the scenario provided. The symptoms and context described point more towards a physiological response related to the sympathetic nervous system and the renin-angiotensin-aldosterone system rather than the other conditions mentioned.