Exam 1- Fluids And Electrolytes

Question 1

Potassium

Answer 1

Major determinant of the resting membrane potential necessary for transmission of nerve impulses.

Most abundant inside the cell

Question 2

Sodium

Answer 2

Regulator of fluids
Maintenance of neuromuscular conduction of nerve impulses
134-145 meq/L
Most abundant outside the cell

Question 3

Capillary Hydrostatic pressure

Answer 3

One of the four forces affecting filtration vs reabsorption

Blood pressure within a capillary (approximately 36 mmHg), referred to as the capillary hydrostatic pressure(P), constitutes an outward filtration force from the plasma space to the interstitium

At the arterial end of capillaries, fluid moves from the plasma space into the interstitial space because the capillary hydrostatic pressure is higher than the Plasma hydrostatic pressure.

Question 4

Oncotic pressure

Answer 4

Heavily influenced by plasma proteins (albumin). Low plasma albumin causes edema as a result of low pressure in the venous system and higher in the interstitial space causing reduction in plasma (venous or capillary) oncotic pressure.

Question 5

Natriuretic peptides

Answer 5

Released from heart when it stretches from too much fluid. Gets rid of fluid. Hormones that include atrial natriuretic peptide (ANP) produced by the myocardial atria, BNP produced by the ventricles, and urodilation within the kidney. Decrease BP and increase sodium and water excretion.

Question 6

RAAS (renin angiotensin-aldosterone system)

Answer 6

1) When circulating blood volume or BP is reduced, renin, an enzyme secreted by the kidney, is released.
2) renin stimulates release of angiotensin 1 from the liver into the bloodstream.
3) the liver releases angiotensin-converting enzyme (ACE) and converts it to angiotensin 2
4) angiotensin 2 causes vasoconstriction and stimulates release of aldosterone
5) aldosterone promotes Na reabsorption by the proximal tubules of the kidneys, thus preserving sodium, blood volume, and BP

Question 7

Hypernatremia

Answer 7

Sodium >147
Movement of water from the cell to the extracellular fluid.

Causes: inadequate water intake, hypertonic saline, over secretion of aldosterone.

Symptoms: confusion, convulsions, cerebral hemorrhage, coma.

Question 8

Hyponatremia

Answer 8

<135
Causes: diuretics, vomiting, diarrhea, hypotonic IV, kidney failure, heart failure, liver failure (ascites)

Symptoms:

Question 9

Hyperkalemia

Answer 9

Causes: Addison’s disease, trauma, insulin deficiency

Symptoms: peaked T waves, arrhythmias

Question 10

Hypokalemia

Answer 10

Causes: loop diuretics, vomiting, diarrhea

Symptoms: flattened t-waves, AV block, bradycardia, paralytic ileus.

Question 11

Hypercalcemia

Answer 11

> 10-12 mg/dl

Causes: hyperparathyroidism, bone nets with calcium reabsorption

Symptoms: nonspecific, fatigue, weakness, lethargy, anorexia, etc.

Inverse relationship with phosphorous. One high, the other is low.

Question 12

Hypocalcemia

Answer 12

<8.5 mg/dl

Inadequate intestinal absorption, massive blood admin, elevated calcitonin, hypoalbuminemia

Symptoms: increased neuromuscular excitability, tingling, muscle spasms, intestinal cramping

Question 13

Phosphate

Answer 13

Buffer in acid-base regulation Energy (ATP) for muscle contraction. Controlled by PTH. Inverse relationship with with calcium.

Low phosphate can be caused by hyperparathyroidism because calcium levels are high.

If high, we worry about the calcium level being low which can lead to arehythmias and laryngospasms.

Question 14

Hydrostatic pressure

Answer 14

Determined by BP and blood volume.

Question 15

Water movement between plasma and interstitial space

Answer 15

Determined by 4 forces:
Capillary hydrostatic pressure (BP)
Capillary (plasma) oncotic pressure 
Interstitial hydrostatic pressure
Interstitial oncotic pressure. 

Mostly relies on capillary pressure

Question 16

Edema

Answer 16

Excessive accumulation of fluid within the interstitial space. Usually a problem with fluid distribution, not fluid excess. Four causes are increase capillary hydrostatic pressure, decreases plasma oncotic pressure, increased capillary membrane permeability, and lymphatic obstruction.

Question 17

Cause of edema from increased capillary hydrostatic pressure

Answer 17

Venous obstruction or sodium and water retention.

Ex: DVT, R-sides HF, tight clothing around extremities, prolonged standing, hepatic obstruction.

Question 18

Cause of edema from decreased plasma oncotic pressure

Answer 18

Losses or diminished production of albumin, which decreases oncotic attraction of fluid into the capillary, leaving fluid in the interstitial spaces.

Ex: liver disease, protein malnutrition, burns

Question 19

Cause of Increased capillary membrane permeability

Answer 19

Inflammation and immune response. Fluid escapes plasma into interstitial spaces.

Ex: shock

Question 20

Cause of Edema from lymphatic obstruction

Answer 20

Lymphatic channels blocked from tumor or infection.

Question 21

SIADH

Answer 21

syndrome of inappropriate secretion of antidiuretic hormone (SIADH)

Excessive secretion of ADH, which decreases diuresis. Increases body water and dilutes urine.

Question 22

Diabetes insipidus

Answer 22

Decreased secretion of ADH. increased diuresis, loss of body water, hypernatremia.

Question 23

Aldosterone

Answer 23

Regulates sodium balance. Increases reabsorption of sodium by distal tubule of the kidney.

Question 24

Magnesium

Answer 24

Major intracellular action. Regulated by PTH. Functions in enzymatic reactions and often interacts with calcium at a cellular level.

Question 25

Atrial natriuretic peptide (ANP)

Answer 25

Stimulate by increased volume in the atria. Causes the increased renal sodium and water excretion.

Question 26

Calcitonin

Answer 26

Stimulated by high plasma calcium.

Causes inhibition of osteoclasts in bone.

Question 27

Filtration

Answer 27

Fluid moving out of the capillary into the interstitial space

Question 28

Osmosis

Answer 28

Fluid moving into or out of cell

Question 29

Total body water

Answer 29

Sum of ICF and ECF. 60% of body weight.
ECF (20%) intravascular, lymph, and interstitial spaces.
ICF (40%)

Question 30

Serum osmolality

Answer 30

Concentration of the blood.

280-300

Question 31

Urine specific gravity

Answer 31

Concentration of the urine
1.005-1.030
High in dehydrated patients, UNLESS they have DI, because they are unable to concentrate urine.

Question 32

ADH

Answer 32

Antidiuretic hormone, aka vasopressin
Pituitary
When released, tells kidney hold (reabsorb) sodium and water. Slows down diuresis.

Stimulated by low sodium, low blood volume or body fluid, and high osmolality of body fluids.

Question 33

Magnesium

Answer 33

Major IC cation.
Interacts with calcium on a cellular level. Necessary for absorption and utilization of other electrolytes. Regulated by PTH.

Relaxant. Without it, our body is tense and irritable.

Question 34

Chloride

Answer 34

Hand in hand with sodium.

Inverse relationship with bicarbonate.

Low chloride level= metabolic alkalosis