Normal Fluid And Electrolytes

Question 1

Which of the following is the most important cation in the extra-
cellular fluid?

(A) Potassium
(B) Calcium
(C) Chloride
(D) Sodium

Answer 1

D.

Sodium is the most prevalent and important cation in the extracellular fluid (135-145 mEq/L). Potassium is the most important cation inside the cell/Intracellular compartment.

Question 2

Calcium is primarily stored in the

(A) Cells and fluid compartments
(B) Cardiac and smooth muscle
(C) Protein and small organic ions
(D) Bones and teeth

Answer 2

D.

Rationale: Calcium is primarily located in the bones and the teeth. Two places for calcium are: in the blood and in bones. When measuring calcium levels, the blood sample typically measures the value of calcium that is in the blood. Calcium is regulated by either being deposited in the bone for storage or taken out of the bone for use in the rest of the body. Calcium is outside the cell/Extracellular compartment.

Question 3

Two main systems for regulating water levels are

(A) Low blood volume and sodium excretion
(B) Osmoreceptors and the renal system
(C) ADH and cellular dehydration
(D) The thirst mechanism and ADH

Answer 3

D.

Rationale: Both thirst and ADH are sensitive to osmolality and extracellular fluid volume.

Question 4

Sodium

Answer 4

135-145 mEq/L

Question 5

Potassium

Answer 5

3.5-5 mEq/L

Question 6

Calcium

Answer 6

9-11 mg/dL

Question 7

Magnesium

Answer 7

1.3-2.1 mEq/L

“Mg British cars can only fit one or two people in that car”

Question 8

A weight change of 1 In corresponds to a fluid volume change of approximately _______.

Answer 8

500 mL

• 1L of water = 2.2 Ibs, equal to 1 kg.
• Weight change of 1 In = fluid volume change of about 500 mL.

Question 9

The renin-angiotensin-aldosterone system (RAAS) is a major regulator of fluid balance. T/F

Answer 9

True.

The RAAS is a major regulator of fluid balance because low blood volume and low blood pressure can rapidly lead to death, the body has many compensatory mechanisms that guard against low plasma volume. These involve specific responses to change how water and sodium are handled to maintain blood pressure. When the kidneys sense that any one of these parameters is getting low, they begin to secrete a substance called renin that sets into motion a group of hormonal and blood vessel responses to ensure that the blood pressure is raised back up to normal. Renin activates angiotensinogen. Angiotensinogen is angiotensin I, which is activated by the enzyme angiotensin-converting enzyme (ACE) to its most active form, angiotensin II. Angiotensin II starts several actions to increase blood volume and blood pressure through vasoconstriction and stimulates adrenal glands to produce aldosterone. Aldosterone tells the kidneys to keep more sodium and water. Kidneys reabsorb water and sodium, preventing them from being excreted into the urine. Thus allows more water and sodium to be returned to the blood, increasing blood pressure, blood volume, and perfusion.

Question 10

A priority problem for a client with dehydration is _______.

Answer 10

Risk for injury.

Monitor vital signs (especially heart rate quality and blood pressure). Patient is at risk for falls because of orthostatic hypotension, dysrhythmias, muscle weakness, and possible confusion. Assess client’s muscle strength, gait stability, and level of alertness. Instruct patient to get up slowly from a lying or standing position and to immediately sit down if they feel light-headed. Stress the importance of asking for assistance to ambulate. Implement fall precautions.
*first thing you should do is take blood pressure lying versus sitting