NSG 211: Exam Review with complete solution latest 2024/2025
Important points:
Water:
Critical for homeostasis (hydrostatic pressure for BP and perfusion)
Solvent of metabolic rxns, transports nutrients (oxygen in blood) to cell and waste from cell
Joint movement
TBW (total body water): infant (inefficient conservation of water -> immature mechanisms)
70%
Elderly (decrease in physiology), women (estrogen promotes adipose, which is
hydrophobic), and obese 50%
Adult males 60%
****most water is IN cells and infants, elderly, obese, and women at greater risk for dehydration
during disease
Compartments:
Intracellular Compartment (ICF): Everything inside cell (70% of water here) ***everything but
water is active transport
Extracellular Compartment (ECF):
• Intravascular fluid (IVF): blood (vascular compartment) ***Labs drawn here
• Interstitial fluid (ISF): bathes cells, supplies cell “transportation” of needs
• Cerebrospinal fluid (CSF)
• Transcellular fluids (pericardial or joint)
Flow of Water AND Nutrients:
1. Cellular membrane (between ISF and ICF): Active Transport (ATP used)
2. IVF (blood) vs. ISF/Cells: free flow of nutrients and wastes because
gradient (ex. Osmosis)
Fluid Balance: water moves freely without use of ATP
Osmosis: flow of water from high concentration of water to low concentration of water
(ex. Moves toward high concentration of salt, higher “osmolarity”)
Two Major (+) Tidal Forces:
Hydrostatic Pressure (Piston, High Tide): “Push” pressure to take fluid out from….
Ex. Sodium (Na+), Blood Volume (blood pressure)
Osmotic Pressure (Sponge, Ebb Tide): Pull or “Sucking” pressure to bring fluid toward…
Ex. Blood proteins (Albumin); RBC’s; even Na+ in veins
+ Capillary Permeability: Ability for fluid to get through membrane (ex. Histamine in inflammation)
Control: Thirst mechanism in the hypothalamus (osmoreceptors to high salt concentration) ->
release of Antidiuretic hormone (ADH) which stimulates kidney reabsorption of pure water
, Low BP: Kidneys secrete reninAngiotensin II which stimulates adrenal glands to
secrete Aldosterone that signals kidney to increase Reabsorption of Na+ (and thus H20
pushing K+ out)
Edema: Intravascular fluid shifts to Interstitial space in EXCESSIVE amounts
Swelling or enlargement of tissues, often localized but can be generalized (anasarca)
Remember: Vascular osmotic pressure: albumin, RBC, Na+
Vascular Hydrostatic Pressure: BP, Lymph obstruction
Causes: Increased Capillary Hydrostatic Pressure (HTN) (increased hydrostatic
pressure) Loss of Plasma proteins (albumin) (low osmotic pressure like with
liver disease) Increased capillary permeability (inflammation)
Obstruction of the lymphatic system (Increased hydrostatic pressure
“Backup”) Rapid Hyponatremia (blood Na+ too low)
Effects: Generalized Edema: Uniform Distribution
Dependent Edema: Gravity-dependent areas ex: Sacral / buttocks or Feet /
legs Pitting (responds to pressure) vs. Nonpitting (no response to pressure)
Weight Gain: from water retention (take daily
weight) Swelling
Tight Clothes
Decreased joint movement = Functional impairment (especially joints)
Pain
Impaired arterial circulation (delayed healing)
“Third Spacing”: not vascular or cellular fluid but instead third space like pleural cavity
Dehydration: insufficient body fluid from excessive loss, inadequate intake, or both
Signs and symptoms: Dry mucous membranes
Decreased skin turgor
Tachycardia (early sign) and then
hypotension Weak, thread-y pulse
Fatigue
Increased HCT or volume percent of RBCs in blood (Blood becomes concentrated)
**** Metabolic Acidosis (lack of circulation ischemia Anaerobic metabolism
Lactic Acid) – results from dehydration or hypoxia
Polydipsia: hypothalamic thirst mechanism (mentioned earlier in guide)
Oliguria: Increased ADH & renin/aldosterone secretion
Sympathetic stimulation (Catecholamines: Epinephrine and Norepinephrine)
Vasoconstriction: Constricting cutaneous blood vessels (pale, cool skin)
Hypernatremia: results in water pulled to blood, so cells lose water
(aka crenation) - cells lose function, decreasing function (result in mental
confusion, decreased level of consciousness)
, Electrolytes:
Sodium (Na+) **: Major Cation (+) in the Extracellular fluid
(high in intravascular / low in intracellular)
Normal Range: 135-145 mEq/L
Controls vascular volume, Important in neurological & muscular
function (involve Action Potential—Na/K Pump), and allows for
diffusion of fluid between vascular and interstitial compartments
(osmosis)
Controlled by Renin Angiotensin Aldosterone System (RAAS) and
driven by kidney glomerular filtration rate (GFR)
Renin Angiotensin II Na-K pump (active transport) (3 Na+ out, 2
K+ In) Maintains high extracellular levels (90% of solutes)
Sources: food, beverages, IV fluids Losses: perspiration, urine, feces
BOTH High and Low Na+ cause Neuro
Changes High: Hypernatremia >145 mEq/L
Causes: Insufficient ADH (excessive loss of “pure” water), loss
of thirst mechanism (HypoTh & Pituitary), watery diarrhea
(more water-loss than salt), Insensible Loss (water vapor loss),
prolonged periods of rapid respiration (thyroid storm)
Manifestations: Increased Osmotic Pressure of IVC, Fluid
pulled / sucked out of cells, Cell crenation (cells “dry up”—
water flows to blood), Decreased cell function, including Dec
LOC, Weakness / Agitation, Increased Thirst; dry, rough mucous
membranes
Decreased Urine Output (Increased ADH secreted) or
Increased Urine Output (ONLY if Diabetes Insipidus--No ADH)
Treatment: Dilute Na in blood
Hypotonic or Isotonic IV Fluids
Low: Hyponatremia <135 mEq/L
Causes: Sweating / Vomiting / Diarrhea, many diuretics:
most cause Na+ & K+ loss, iatrogenic:, giving HYPOtonic IV
fluids Hormonal Imbalances - low aldosterone (Addison’s Dz-
Adrenal Insuff), SIADH: Primary Dz and paraneoplastic
syndromes
Manifestations: Impaired nerve function: confusion; fluid
imbalance: hypotension, edema; decreased osmotic pressure in
IVC - Hypovolemia / Hypotension; Brain cells may swell
(more Na in cells)
- Cerebral edema Confusion, coma, sz, death
Treatment: Give Na+, Usually Hypertonic IV Fluids
Potassium (K+) **: Normal range 3/5-5 mEq/L
Major Intracellular Cation (+) : Serum Levels are LOW, most is
inside cell Major control is *RENAL (both basic excretion and
Aldosterone / Na+
control)
Controlled by Na-K pump (active transport), which is *Insulin-dependent
Important points:
Water:
Critical for homeostasis (hydrostatic pressure for BP and perfusion)
Solvent of metabolic rxns, transports nutrients (oxygen in blood) to cell and waste from cell
Joint movement
TBW (total body water): infant (inefficient conservation of water -> immature mechanisms)
70%
Elderly (decrease in physiology), women (estrogen promotes adipose, which is
hydrophobic), and obese 50%
Adult males 60%
****most water is IN cells and infants, elderly, obese, and women at greater risk for dehydration
during disease
Compartments:
Intracellular Compartment (ICF): Everything inside cell (70% of water here) ***everything but
water is active transport
Extracellular Compartment (ECF):
• Intravascular fluid (IVF): blood (vascular compartment) ***Labs drawn here
• Interstitial fluid (ISF): bathes cells, supplies cell “transportation” of needs
• Cerebrospinal fluid (CSF)
• Transcellular fluids (pericardial or joint)
Flow of Water AND Nutrients:
1. Cellular membrane (between ISF and ICF): Active Transport (ATP used)
2. IVF (blood) vs. ISF/Cells: free flow of nutrients and wastes because
gradient (ex. Osmosis)
Fluid Balance: water moves freely without use of ATP
Osmosis: flow of water from high concentration of water to low concentration of water
(ex. Moves toward high concentration of salt, higher “osmolarity”)
Two Major (+) Tidal Forces:
Hydrostatic Pressure (Piston, High Tide): “Push” pressure to take fluid out from….
Ex. Sodium (Na+), Blood Volume (blood pressure)
Osmotic Pressure (Sponge, Ebb Tide): Pull or “Sucking” pressure to bring fluid toward…
Ex. Blood proteins (Albumin); RBC’s; even Na+ in veins
+ Capillary Permeability: Ability for fluid to get through membrane (ex. Histamine in inflammation)
Control: Thirst mechanism in the hypothalamus (osmoreceptors to high salt concentration) ->
release of Antidiuretic hormone (ADH) which stimulates kidney reabsorption of pure water
, Low BP: Kidneys secrete reninAngiotensin II which stimulates adrenal glands to
secrete Aldosterone that signals kidney to increase Reabsorption of Na+ (and thus H20
pushing K+ out)
Edema: Intravascular fluid shifts to Interstitial space in EXCESSIVE amounts
Swelling or enlargement of tissues, often localized but can be generalized (anasarca)
Remember: Vascular osmotic pressure: albumin, RBC, Na+
Vascular Hydrostatic Pressure: BP, Lymph obstruction
Causes: Increased Capillary Hydrostatic Pressure (HTN) (increased hydrostatic
pressure) Loss of Plasma proteins (albumin) (low osmotic pressure like with
liver disease) Increased capillary permeability (inflammation)
Obstruction of the lymphatic system (Increased hydrostatic pressure
“Backup”) Rapid Hyponatremia (blood Na+ too low)
Effects: Generalized Edema: Uniform Distribution
Dependent Edema: Gravity-dependent areas ex: Sacral / buttocks or Feet /
legs Pitting (responds to pressure) vs. Nonpitting (no response to pressure)
Weight Gain: from water retention (take daily
weight) Swelling
Tight Clothes
Decreased joint movement = Functional impairment (especially joints)
Pain
Impaired arterial circulation (delayed healing)
“Third Spacing”: not vascular or cellular fluid but instead third space like pleural cavity
Dehydration: insufficient body fluid from excessive loss, inadequate intake, or both
Signs and symptoms: Dry mucous membranes
Decreased skin turgor
Tachycardia (early sign) and then
hypotension Weak, thread-y pulse
Fatigue
Increased HCT or volume percent of RBCs in blood (Blood becomes concentrated)
**** Metabolic Acidosis (lack of circulation ischemia Anaerobic metabolism
Lactic Acid) – results from dehydration or hypoxia
Polydipsia: hypothalamic thirst mechanism (mentioned earlier in guide)
Oliguria: Increased ADH & renin/aldosterone secretion
Sympathetic stimulation (Catecholamines: Epinephrine and Norepinephrine)
Vasoconstriction: Constricting cutaneous blood vessels (pale, cool skin)
Hypernatremia: results in water pulled to blood, so cells lose water
(aka crenation) - cells lose function, decreasing function (result in mental
confusion, decreased level of consciousness)
, Electrolytes:
Sodium (Na+) **: Major Cation (+) in the Extracellular fluid
(high in intravascular / low in intracellular)
Normal Range: 135-145 mEq/L
Controls vascular volume, Important in neurological & muscular
function (involve Action Potential—Na/K Pump), and allows for
diffusion of fluid between vascular and interstitial compartments
(osmosis)
Controlled by Renin Angiotensin Aldosterone System (RAAS) and
driven by kidney glomerular filtration rate (GFR)
Renin Angiotensin II Na-K pump (active transport) (3 Na+ out, 2
K+ In) Maintains high extracellular levels (90% of solutes)
Sources: food, beverages, IV fluids Losses: perspiration, urine, feces
BOTH High and Low Na+ cause Neuro
Changes High: Hypernatremia >145 mEq/L
Causes: Insufficient ADH (excessive loss of “pure” water), loss
of thirst mechanism (HypoTh & Pituitary), watery diarrhea
(more water-loss than salt), Insensible Loss (water vapor loss),
prolonged periods of rapid respiration (thyroid storm)
Manifestations: Increased Osmotic Pressure of IVC, Fluid
pulled / sucked out of cells, Cell crenation (cells “dry up”—
water flows to blood), Decreased cell function, including Dec
LOC, Weakness / Agitation, Increased Thirst; dry, rough mucous
membranes
Decreased Urine Output (Increased ADH secreted) or
Increased Urine Output (ONLY if Diabetes Insipidus--No ADH)
Treatment: Dilute Na in blood
Hypotonic or Isotonic IV Fluids
Low: Hyponatremia <135 mEq/L
Causes: Sweating / Vomiting / Diarrhea, many diuretics:
most cause Na+ & K+ loss, iatrogenic:, giving HYPOtonic IV
fluids Hormonal Imbalances - low aldosterone (Addison’s Dz-
Adrenal Insuff), SIADH: Primary Dz and paraneoplastic
syndromes
Manifestations: Impaired nerve function: confusion; fluid
imbalance: hypotension, edema; decreased osmotic pressure in
IVC - Hypovolemia / Hypotension; Brain cells may swell
(more Na in cells)
- Cerebral edema Confusion, coma, sz, death
Treatment: Give Na+, Usually Hypertonic IV Fluids
Potassium (K+) **: Normal range 3/5-5 mEq/L
Major Intracellular Cation (+) : Serum Levels are LOW, most is
inside cell Major control is *RENAL (both basic excretion and
Aldosterone / Na+
control)
Controlled by Na-K pump (active transport), which is *Insulin-dependent
