Body Fluids and Electrolytes Quiz

Fluid and Electrolyte Imbalances

• Fluid and electrolyte imbalances are a critical concern in nursing practice.
• Maintaining homeostasis is essential, involving a balance of fluids and electrolytes.
• Fluid distribution and movement between compartments (intracellular and extracellular) are key.
• Edema results from an imbalance in the fluid distribution.
• Imbalances in isotonic, hypotonic, and hypertonic solutions affect cell size.
• The renin-angiotensin-aldosterone system, along with antidiuretic hormone, controls water balance.
• Clinical exemplars illustrate the effects of fluid and electrolyte imbalances.

Objective 1

• Compare the distribution and movement of fluid in body compartments.
• The body is made up of 60% water.
• Water is distributed both intracellular and extracellular.
• Plasma, interstitial fluid, and transcellular fluid are examples of extracellular fluid.
• Intracellular fluid is the fluid inside the cell.

Homeostasis

• Homeostasis is a dynamic process.
• A receptor detects an imbalance (stimulus).
• The signal is sent to the control center.
• The signal travels via an efferent pathway to the effector.
• The effector responds.
• The output restores balance.

Fluids in the Body

• 60% of healthy adults' weight is water.
• Water is essential for cellular function and metabolic reactions.
• It transports nutrients and waste products.
• Water acts as a lubricant, insulator, and shock absorber.
• Water helps regulate body temperature.
• Intracellular fluid (ICF) comprises 40% of total body weight.
• Extracellular fluid (ECF) accounts for 20% of total body weight.
  • Interstitial fluid is 15% of total body weight.
  • Plasma is 5% of total body weight.
  • Transcellular fluid is 1% of total body weight.

Distribution and Composition of Body Fluids

• ICF is the fluid inside cells.
• ECF is the fluid outside cells.
• ECF is divided into interstitial fluid and plasma.
• Transcellular fluid is a specialized ECF.
• Total body water comprises 60% of body weight, distributed between ICF and ECF.

Movement of Body Fluids

• Fluid movement across cell and capillary membranes is essential.
• These movements are facilitated by osmosis, diffusion, filtration, and reabsorption.

Osmosis

• Osmosis is the movement of water across a semipermeable membrane.
• It moves from an area of lower solute concentration to higher solute concentration.
• The concentration gradient drives this movement.
• Solutes and solvents play a key role in osmosis.

Factors of Osmosis

• Osmotic pressure is the pressure required to prevent osmosis.

• Osmolality is a measure of solute concentration.

• Tonicity describes the effect of a solution on cell volume.

  • Isotonic solutions have the same solute concentration as the cell.
  • Hypertonic solutions have a higher solute concentration than the cell.
  • Hypotonic solutions have a lower solute concentration than the cell.

Filtration

• Filtration involves the movement of fluids across capillaries.
• Hydrostatic pressure pushes fluid out.
• Osmotic pressure helps bring it back in.

Reabsorption

• Fluids move from the interstitial space back into capillaries.
• Driven by osmotic pressure.

Diffusion

• Movement of solutes from higher concentration to lower concentration across a semipermeable membrane.
• Size, concentration, and temperature affect diffusion rate.

Objective 3 & 4

• Describe the control of cell volume and the effect of isotonic, hypotonic, and hypertonic solutions on cell size.
• Identify select intravenous (IV) fluids as isotonic, hypertonic, or hypotonic.

IV Solutions

• Classified based on tonicity relative to blood.
• Crystalloids (e.g., Normal Saline, Lactated Ringer's) are isotonic, hypertonic, or hypotonic.
• Colloids (e.g., Albumin) are mainly used for volume expansion.

Objective 5

• Discuss the roles of antidiuretic hormone (ADH) and the renin-angiotensin-aldosterone system (RAAS) in the regulatory processes for water balance in the body.

Objective 6

• Apply concepts of altered fluid and electrolyte balance to selected clinical exemplars.
• Understanding fluid balance and altered fluid and electrolyte balance is crucial in patient care.
• Clinical exemplars include various scenarios like dehydration, hypotonic IV fluids, and electrolyte imbalances.
• Each specific clinical exemplar requires a different approach to treatment.

Maintaining Homeostasis

• Keeping fluid and electrolytes balanced through intake and output, using hormones ADH and RAAS, is key.

Regulating Electrolytes

• Electrolytes hold an electrical charge that is essential for maintaining fluid balance, contributing to acid-base regulation, facilitating enzyme reactions, and transmitting neuromuscular reactions.
• Electrolyte imbalance may cause various health problems.

Basic Electrolyte Functions

• Magnesium: Muscle relaxation.
• Phosphorus: Muscle contraction.
• Potassium: Intracellular excitation, essential for nerve function.
• Calcium: Neuronal excitation and bone building.
• Chloride: Acid-base balance.
• Sodium: Extracellular excitation.

Compensation

• Body systems attempt to correct fluid and electrolyte imbalances by shifting fluids.
• Electrolyte relationships often oppose one another.

Magnesium Mg+

• Intracellular cation.
• Small extracellular amount.
• Regulated by PTH and the sodium-potassium pump.
• Nerve and smooth muscle relaxant.
• Imbalance may result in muscle relaxation or excitation problems.

Calcium Ca+

• Primarily intracellular cation.
• Essential for bone health.
• Crucial for nerve and muscle function.
• Regulated by vitamin D, calcitonin, and PTH.
• Imbalance leads to either too much or not enough calcium

Potassium K+

• Major intracellular cation.
• Plays a critical role in cellular activity.
• Vital for nerve and muscle function, especially in the heart.
• Imbalance often presents with serious cardiac or neuromuscular complications.

Sodium Na+

• Most abundant extracellular cation.
• Regulates fluid balance.
• Essential for nerve impulse transmission and muscle contraction
• Imbalance can lead to serious health consequences.

Chloride Cl-

• Most abundant anion in extracellular fluid (ECF).
• Paired with sodium to maintain electrical neutrality.
• Crucial for acid-base balance, serum osmolarity and fluid balance.
• Imbalances are often linked to other electrolyte problems.

Fluid Volume Imbalances

• Hypovolemia: Low blood volume (dehydration).
• Hypervolemia: High blood volume.
• Edema: Fluid build-up in tissues.

Dehydration

• Loss of extracellular fluid.
• Causes can be decreased intake, increased output. symptoms may include dry mouth, poor skin turgor.
• Assessment includes measurement of vital functions.

Hypervolemia

• High blood volume, often accompanied by edema, common causes include heart failure or kidney disease.

Diagnosing Fluid Imbalance

• Multiple tests help diagnose imbalances.
• Key indicators include blood chemistry analysis, urine output, and hematocrit.