Fluid Imbalances in Human Physiology

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Questions and Answers

What condition is associated with high osmotic pressure resulting in fluid shifting from ICF to ECF?

Uncontrolled diabetes mellitus (correct)

Diabetes insipidus

Hypovolemia

Renal dysfunction

Which symptom is commonly associated with hypovolemia?

Increased urine output

Hypotension while standing (correct)

Hypernatremia

Elevated platelet count

In diabetes insipidus, what occurs due to insufficient ADH?

Decreased urination

Fluid accumulation in tissues

High osmolarity (correct)

Increased fluid retention

What is a possible renal consequence of fluid shifts and imbalances?

Increased urine concentration Signup and view all the answers

Which of the following is a characteristic finding in hypovolemia related to skin assessment?

Dry skin and reduced turgor Signup and view all the answers

What is the primary component of total body fluid in humans?

Water Signup and view all the answers

Which compartment contains the majority of total body water?

Intracellular fluid (ICF) Signup and view all the answers

What does osmosis specifically refer to in body fluid movement?

Movement of water from high to low water concentration Signup and view all the answers

What is the primary goal of body fluid balance?

Achieve homeostasis of solute and water Signup and view all the answers

Which component is NOT part of extracellular fluid (ECF)?

Intracellular fluid (ICF) Signup and view all the answers

In body fluid balance, diffusion refers to the movement of which substance?

Electrolytes from high to low concentration Signup and view all the answers

What percentage of total body water is typically found in extracellular fluid (ECF)?

20% Signup and view all the answers

Which of the following best describes the role of a semi-permeable membrane in fluid movement?

Restricts movement based on solute size Signup and view all the answers

What role does aldosterone play in the body fluid homeostasis?

Increases fluid retention by promoting sodium reabsorption Signup and view all the answers

What is the primary cause of edema related to high hydrostatic pressure?

Excess fluid in the bloodstream due to sodium retention Signup and view all the answers

What indicates a life-threatening condition of edema?

Cerebral edema Signup and view all the answers

Which mechanism is triggered by the hypothalamus when fluid levels are low?

Conscious desire to drink fluids Signup and view all the answers

What defines hypervolemia?

Accumulation of excess fluid in the body Signup and view all the answers

Which of the following is a common symptom of hypovolemia?

Decreased urine output Signup and view all the answers

What is the function of Natriuretic peptides in fluid balance?

Excrete sodium and water from the body Signup and view all the answers

What physiological change occurs when the body attempts to compensate for low cardiac output?

Fluid retention due to RAAS activation Signup and view all the answers

How does inflammation contribute to fluid imbalance?

By increasing capillary permeability and fluid shifts Signup and view all the answers

In the context of fluid balance, what does SIADH primarily cause?

Excessive fluid retention and dilutional hyponatremia Signup and view all the answers

Which type of edema is characterized by tissue displacement and can lead to impaired movement?

Pitting edema Signup and view all the answers

What is the most immediate effect of excessive fluid retention in the body?

Increased blood pressure Signup and view all the answers

What is a common assessment finding in a patient with hypervolemia?

Hypertension and peripheral edema Signup and view all the answers

What is a common symptom associated with hypovolemia?

Dry mucosa Signup and view all the answers

What is the primary cause of hypovolemic hypernatremia?

Fluid loss without sodium loss Signup and view all the answers

Which of the following is NOT a risk factor for hyperkalemia?

Increased dietary salt intake Signup and view all the answers

What is a common cardiovascular symptom of hypokalemia?

Tachycardia Signup and view all the answers

Which condition is associated with a serum calcium level exceeding 10 mg/dL?

Hypercalcemia Signup and view all the answers

Which electrolyte imbalance is characterized by increased neural excitability?

Hypocalcemia Signup and view all the answers

What laboratory finding is associated with hypercalcemia?

Muscle weakness Signup and view all the answers

Which electrolyte imbalance can result from excessive alcohol consumption?

Hypokalemia Signup and view all the answers

What is the normal range for serum potassium levels?

3.5 – 5 mEq/L Signup and view all the answers

Which hormone is primarily responsible for regulating serum calcium levels?

Parathyroid hormone (PTH) Signup and view all the answers

What is a common symptom of hypernatremia related to cellular dehydration?

Confusion Signup and view all the answers

What physiological process is potassium involved in?

Action potential initiation Signup and view all the answers

Which electrolyte imbalance may cause dyspnea and pulmonary congestion?

Hypervolemic hypernatremia Signup and view all the answers

What is the normal range for serum phosphorus levels?

2.5 – 4.5 mg/dL Signup and view all the answers

What is the normal concentration range for Sodium (Na+) in ECF?

135 – 145 mEq/L Signup and view all the answers

What occurs during hypernatremia?

Serum Na+ levels exceed 145 mEq/L Signup and view all the answers

How does sodium primarily affect fluid balance in the body?

By controlling the osmotic activity of body fluids Signup and view all the answers

What is the primary electrolyte found in intracellular fluid (ICF)?

Potassium (K+) Signup and view all the answers

Which of the following could cause hypovolemic hyponatremia?

Diarrhea and vomiting Signup and view all the answers

What effect does hypertonic solution have on cells?

Cells shrink due to fluid loss Signup and view all the answers

What is one major consequence of severe sodium imbalance?

Altered cerebral fluid balance Signup and view all the answers

Which assessment finding is indicative of hyponatremia?

Headaches and fatigue Signup and view all the answers

What is the primary function of the Na+/K+ pump in cells?

To maintain electrical gradients across membranes Signup and view all the answers

Which condition can dilute sodium levels in the body?

Fluid overload Signup and view all the answers

What is the characteristic of an isotonic solution?

Osmotic pressure is equal to body fluids Signup and view all the answers

What indicates hypernatremia in a patient?

Na+ concentration > 145 mEq/L Signup and view all the answers

How does osmotic pressure affect fluid movement in the body?

Pushes fluid from high to low electrolyte concentration Signup and view all the answers

Which of the following is a potential result of cellular edema?

Increased intracranial pressure Signup and view all the answers

What is the serum phosphorus level associated with hypophosphatemia?

< 2.5 mg/dL Signup and view all the answers

Which condition is characterized by a serum magnesium level greater than 2.5 mg/dL?

Hypermagnesemia Signup and view all the answers

What symptoms are commonly associated with hypophosphatemia?

Weakness and confusion Signup and view all the answers

What effect does elevated PTH have on phosphate retention?

Reduces phosphate retention Signup and view all the answers

Which of the following is a common cause of hyperphosphatemia?

Renal failure Signup and view all the answers

Which electrolyte imbalance is commonly associated with hypomagnesemia?

Hypocalcemia Signup and view all the answers

Hyperchloremia is typically observed with which condition?

Dehydration Signup and view all the answers

Which of the following is a symptom of hypermagnesemia?

Hyporeflexia Signup and view all the answers

What serum chloride levels indicate hypochloremia?

< 98 mEq/L Signup and view all the answers

What is a common cause of hypochloremia?

Chronic respiratory acidosis Signup and view all the answers

What role does magnesium play in the body?

Essential for ATP production Signup and view all the answers

Which of the following describes hyperchloremia?

Serum chloride levels exceeding 106 mEq/L Signup and view all the answers

Study Notes

Fluid and Electrolyte Imbalance

60% of human body is fluid, mostly water
Majority component in cells and bloodstream
Solvent for body solutes/electrolytes
Fluid constantly shifts between compartments

Body Fluid Compartments

ICF: Intracellular fluid (within cells), 40% of total body weight
ECF: Extracellular fluid (bloodstream), 20% of total body weight
Interstitial fluid (between cells, tissue), part of ECF

Body Fluid Balance and Movement

Homeostasis Goal: balance/equilibrium of solute and water across membrane
Diffusion: passive movement from high to low concentration
Osmosis: passive movement of water from high to low water concentration; semi-permeable membrane limits solute size
Facilitated transport: active carrier proteins carry molecules through plasma membrane; ex: glucose facilitated by insulin
Active transport: active movement against gradient; ex: Na+/K+ pump balances K+ ICF, Na+ ECF

Body Fluid Balance- Osmotic Movement

Homeostasis: maintain equilibrium between body fluid (water) and solutes (electrolytes, proteins)
Starling's law of capillary forces: osmotic and hydrostatic pressure in balance/opposition; more fluid may shift to ICF (swelling/edema) or ECF (dehydration)
Hydrostatic pressure: water pushes fluid from vessels (high to low pressure) into cells
Osmotic pressure: water pulled into cells from vessels (high to low)

Homeostasis Interrupted

Fluid imbalances: fluid > or < “normal” inhibits body functions
Body fluid functions: Universal biologic solvent; regulate electrolyte distribution in ECF and ICF; transport hormones, nutrients, toxins and waste products; transport O2 to cells; CO2 to lungs; regulate temperature

Fluid Homeostasis

Fluid Homeostasis: balance of fluid intake & output
Osmolarity: solute level in fluid, mechanism to monitor/assess body fluid status
Mechanisms to maintain fluid homeostasis: thirst; ADH; renin-angiotensin-aldosterone system (RAAS); natriuretic peptides

Body Fluid Homeostasis: Renin-Angiotensin-Aldosterone System (RAAS)

Hypotension, hypovolemia: low cardiac output (CO) and low fluid volume
Low circulating fluid: reduced renal perfusion
Kidneys: release renin, start RAAS compensation
Renin converts angiotensin to angiotensin 1
ACE (lungs) converts angiotensin 1 to angiotensin 2 (vasoconstrictor), increases blood pressure
Triggers adrenal glands: release aldosterone (fluid retention), reabsorption of Na+, retention of Na + water
Increased BP & fluid retention: return to normal blood volume

Fluid Imbalance: Edema

Edema: swelling; increase in ISF and/or ICF
Can hold 10-30L additional fluid
Pitting edema: tissues displace; exceed tissue absorption capacity; usually in legs
Nonpitting edema: firm; accumulations of plasma proteins (inflammation)
Etiology (cause): high hydrostatic pressure, sodium retention, low osmotic pressure, inflammation, injury, low albumin

Fluid Imbalance: Assessment

Symptoms determined by edema location: impaired movement, function (swelling)
Increased extremity circumference: weight gain (1L=2.2 lbs) decreased blood flow (hypoxia)
Wounds/ulcerations: skin susceptibility to injury
Life-threatening edema: brain (cerebral), lungs (pulmonary), larynx (laryngeal)

Fluid Imbalances: Hypervolemia

Excess fluid in body (overhydration), fluid volume overload
Etiology (causes): high hydrostatic pressure (too much ECF); fluid shifts into interstitial fluid; Excess sodium; heart failure; Excess ADH (fluid retained)
Excess ADH: **excess retention of fluid, (lack of diuresis) **; SIADH - dilutional hyponatremia; cirrhosis of liver - stimulates ADH release, impairs blood flow through liver and fluid accumulates (ascites)
Assessment (clinical assessment): Jugular venous pressure; body weight; fluid balance

Fluid Imbalances: Hypovolemia

Diminished fluid in body/bloodstream (dehydration); fluid volume deficit
Causes: reduced fluid intake; excess fluid loss (ex: burn injuries, perspiration, diarrhea, vomiting); high osmotic pressure; insufficient ADH; diabetes insipidus; hypernatremia
Complications: renal dysfunction related to decreased excretion of waste products
Assessment : CV: low cardiac volume - hypotension (esp w/standing); tachycardia (elev HR to compensate low BP); reduced peripheral perfusion; weak/thready pulse; decreased arterial and venous pressure; Neuro: dizzy; weak; loss of consciousness; HA (poor cerebral blood/oxygen); Renal: low Urine output (<30ml/hr); high specific gravity

Electrolytes

Electrolytes: charged ions (cations+, anions-)
Essential for metabolism, energy production
Cell function: nerve and muscle cells
Impulse conduction: action potentials
Muscle contraction
Na+, K+: primary role in cell depolarization and repolarization
Solutes: dissolved in ICF and ECF
Protein molecules: essential body solute
Maintains fluid balance, prevents fluid shift
Transported substances throughout body

Electrolyte Balance- Concentration

Normal Concentration: specific ranges varying between ICF and ECF.
Sodium (Na+); Potassium (K+); Calcium (Ca++); Chloride (Cl-); Magnesium (Mg+); Phosphate

Electrolyte Balance - Movement

Osmotic pressure: Electrolytes/solutes (proteins) pull water from cells (diffusion) and from ICF to ECF, to equalize concentration.
Osmolarity: solutes/liter of body fluid; high serum osmolarity = excess electrolyte in blood; low serum osmolarity = reduced electrolyte in blood.
Tonicity: osmotic pressure difference between two solutions; Isotonic; Hypotonic; Hypertonic.
No fluid movement; Low; High osmolarity, respectively.

Sodium (Na+)

Normal Range: 135-145 mEq/L
90% of ECF cations
Imbalances: Hyponatremia (Serum Na++ < 135 mEq/L) ; Hypernatremia (Serum Na++ > 145 mEq/L)
Primary role: Fluid volume balance
Elevated Na+: Fluid retention
Other functions: nerve impulse conduction; critical to muscle contraction
Facilitates membrane transport through Na+/K+ pump

Sodium & Body Fluid

Wherever sodium goes, water will follow: (sodium concentration regulates ECF volume and majority of osmotic activity)
Hyponatremia: low ECF Na+ concentration; fluid shifts from ECF to ICF (cellular edema);
Hypernatremia: High ECF Na+ concentration; fluid shifts from ICF to ECF (cellular dehydration)

Sodium Imbalance

Severe Na imbalance: most dramatic to brain due to effect on cerebral fluid balance (or imbalance).
Normal brain/normonatremia; Acute hyponatremia; Acute hypernatremia

Electrolyte Imbalance: Hyponatremia

Hypervolemic: fluid overload dilutes Na+ (renal failure, heart failure); Excess fluid most common cause of hyponatremia; SIADH (syndrome of inappropriate ADH).
Assessment: symptoms manifest <125 mEq/mL; Neuro/MS: HA, confusion, weakness, fatigue; muscle cramps; Severe (r/t cerebral edema): lethargy, seizure, coma, death; CV (excess volume): HTN, bounding pulse; Gl (excess volume, ascites): nausea, vomiting, diarrhea

Electrolyte Imbalance: Hypovolemic Hyponatremia

Etiology: Renal loss (diuretics, renal disease); Non-renal loss (vomiting, Gl suctioning, wound drainage, sweating, burns); Symptoms manifest <125 mEq/mL
Assessment: symptoms related to hypovolemia & hyponatremia/cell edema; Neuro/MS: HA, confusion, weakness, fatigue; muscle cramps; Severe (r/t cerebral edema): lethargy, seizure, coma, death; CV (hypovolemia): tachycardia, hypotn; Renal: low urine output (oliguria), azotemia; General (hypovolemia): thirst, poor skin turgor, dry mucosa

Electrolyte Imbalances: Hypernatremia

Hypovolemic Hypernatremia: excess fluid loss (fluid lost, Na left behind); fever, diarrhea, tachypnea
Assessment: Symptoms manifest >155 mEq/mL; symptoms r/t cellular dehydration; Neuro: restlessness, irritable, muscle twitching/spasms; Severe (r/t cerebral dehydration): lethargy, seizure, coma, death; CV: tachycardia, hypotn; General: thirst, fever

Electrolyte Imbalance: Hypervolemic Hypernatremia

Etiology: hyperaldosteronism; excess salt intake, antacids with sodium bicarbs**
Assessment: Symptoms manifest > 155 mEq/mL; Neuro: restless, irritable, muscle twitching/spasms, severe cerebral dehydration (seizure, coma, death); CV: tachycardia, hypotn; Resp: dyspnea, pulmonary congestion; general (hypervolemia): weight gain

Potassium (K+)

Normal Range: 3.5-5 mEq/L
Primary cation in ICF
Hypokalemia: Serum K+< 3.5 mEq/ml
Hyperkalemia: Serum K+ > 5 mEq/ml
Primary role: Maintain action potentials; K+ gradient
Other functions: cell depolarization, cardiac rhythms, muscle contraction, acid-base balance

Potassium & PH

Intracellular pH Buffer: H+ and K+ ion exchange, shift between ICF and ECF to buffer pH; Alkalosis (high pH): H+ moves out of cell; K+ into cell (hypokalemia); Acidosis (low pH): H+ moves into cell; K+moves out (hyperkalemia)

Electrolyte Imbalance: Hypokalemia

Etiology: Excess K+ excretion (renal); medication side effects (diuretics); severe GI loss(vomiting, diarrhea); inadequate intake of K+(NPO status, bariatric surgery); alkalosis
Assessment: Decreases cell excitability; action potential; CV: hypoTN (low BP); Flattened T wave; prolonged PR interval; Neuro/MS: muscle fatigue, weakness, leg cramps; General: anorexia, n/v (decreased peristalsis)

Electrolyte Imbalance: Hyperkalemia

Etiology: excess K+ retention; decreased K+ excretion (renal failure); massive injury/burn; acidosis
Assessment: increases excitability; action potential; Decreases excitability threshold; CV: ventricular dysrhythmias; peaked T wave; widened QRS interval; Neuro/MS (early): numbness tingling, muscle cramps, confusion.

Calcium (Ca++)

Normal Range: 8.7-10 mg/dL
99% of Ca+ bound in bones, teeth (primary mineral)
1% in circulation, ECF (measure serum levels)
Hypocalcemia: Serum Ca++< 8.7 mg/dL
Hypercalcemia: Serum Ca++ > 10 mg/dL
Serum (free) calcium: nerve impulse conduction/excitability, muscle contraction; blood clotting factor
Regulation: parathyroid hormone (PTH); decreased serum calcium stimulates PTH, calcium mobilized from bone to stabilize serum calcium

Electrolyte Imbalances: Hypocalcemia

Etiology: insufficient supply of calcium; inadequate calcium or Vitamin D intake; hypoparathyroidism; increased excretion of calcium; renal disease, diarrhea; wound drainage.
Assessment: increased neural excitability; neuro: muscle twitch/cramps , tetany, hyperreflexia, paresthesia (numbness, tingling); CV: hypoTN, arrhythmias; Resp: dyspnea, laryngospasm.

Electrolyte Imbalances: Hypercalcemia

Etiology: metastatic cancer; immobility; hyperparathyroidism; excessive calcium or Vitamin D intake
Assessment: decreased neural excitability; Neuro: muscle weakness, hyporeflexia/ataxia; CV: HyperTN, arrhythmias; MS: osteopenia, bone pain, pathologic Fx; GI: constipation, anorexia, n/v, cramps, hypoactive BS.

Phosphorus

Normal Range: 2.5-4.5 mg/dL
ICF anion: 14% in cells; 85% in bones
Hypophosphatemia: Serum Phosphorus< 2.5 mg/dL
Hyperphosphatemia: Serum Phosphorus > 4.5 mg/dL
Roles: formation of teeth and bones; essential to carb, protein, lipid metabolism; ATP creation; building block of nucleic acids (RNA & DNA); regulate acid-base as buffer.
Regulation: renal; PTH (elevated reduces phosphate retention; inverse relationship to calcium)

Hypophosphatemia & Hyperphosphatemia

Hypophosphatemia: Serum Phosphorus <2.5mg/dL; decreased intestinal absorption (diarrhea, prolonged antacids, low Vit D); malnutrition; alcoholism; increased renal loss; alkalosis
Assessment: decrease energy, deficiency in ATP; Neuro: tremors, paresthesia, weakness; MS: weak, joint stiffness; blood: Hemolytic anemia (hemolysis); impaired WBC & platelet function.
Hyperphosphatemia: Serum Phosphorus > 4.5mg/dL; renal failure (reduced secretion); rhabdomyolysis (rapid production).
Assessment: S/S related to complementary calcium deficit; Neuro: paresthesia, tetany; CV: Hypotension, arrhythmias.

Magnesium (Mg++)

Normal Range: 1.5-2.5 mg/dL
ICF cation: Majority stored in bone
Hypomagnesemia: Serum magnesium <1.5mg/dL; Increased excretion/loss;
Hypermagnesemia: Serum magnesium >2.5mg/dL; Decreased excretion
Roles: Essential for absorption of Calcium & Vitamin D; Co-factor; enzymatic reactions; Facilitates ATP (Na-K pump); Transmits electrical impulses; Renal, Gl system; PTH stimulates magnesium reabsorption

Electrolyte Imbalance: Chloride (Cl-)

Normal Range: 98-106 mEq/L
ECF anion: majority stored in bone; Hypochloremia (serum chloride <98 mEq/L); Hyperchloremia (serum chloride > 106 mEq/L).
Roles: essential for regulation of fluid (BP); pH balance; supports nerve impulse conduction, muscle contraction
Facilitates absorption of nutrients
Regulation: renal balances through selective absorption, excretion.

Hypochloremia & Hyperchloremia

Hypochloremia: Serum Chloride < 98 mEq/L; increased excretion/loss of chloride, renal disease, excess sweating, pH imbalance (Chronic respiratory acidosis, metabolic alkalosis).
Hyperchloremia: Serum Chloride > 106 mEq/L; rare; dehydration; medications (diuretics); heat exposure; decreased fluid intake; decreased excretion of chloride (renal disease).

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Description

This quiz examines key concepts related to fluid imbalances in human physiology, including conditions like diabetes insipidus and their associated symptoms. Test your knowledge on osmotic pressure, hypovolemia, and body fluid components. Perfect for students of medical science or those studying human biology.