Fluid, Electrolyte, and Acid-Base Homeostasis Flashcards
Adult body fluid
Women contain 45% solids and 55% fluids
Males contain 40% solids and 60% fluids
2/3 is intercellular fluids
1/3 is extracellular fluids of that
80% is interstitial fluid and 20% is in the plasma
Plamsa Membrane
Separates cells from interstitial fluid
Blood Vessele walls
Divide interstitial fluid from blood plasma
Capillary walls
Thin enough to allow exchange of water and solutes between blood plasma and interstitial fluid
Filtration, Reabsorption, Diffusion and Osmosis
Allow the continuous exchange of water and solutes among body fluids
How does the body gain water?
By ingestion and metabolic synthesis
How does the body lose water?
Through urination, perspiration, exhalation and feces
Water gain volume
200mL is from water
700mL is from ingested foods
1600 mL is from ingested liquids
Water loss volume
100mL is from GI tract
600mL is from skin
1500mL is from the kidneys
Aerobic respiration and metabolic water
The level if AR determines the volume of MW fromed
The amount of water formed is directly proportional to the amount of ATP produced
When water loss is greater than water gain then dehydration occurs leading to thirst
How does elimination of excess body waters occur
Through urination
Two main solutes in urine
Sodium ions ( Na+ ) and Chloride Iona ( CI-)
Urinary salt loss
Water follows salt, wherever sodium chloride moves to, WATER WILL FOLLOW
Increased blood volume pathway
If you increase sodium chloride, plasma concentration increases. When this happens you move water from intercellular flies into the plasma, increasing the blood volume, and this increases the stretching of heart muscle.
Causing increase release of atrial natriuretic peptide.
This will result in the decrease reabsorption of sodium chloride and greater loss of sodium in the urine.
Resulting in increased water loss In urine
Leading to decrease in blood volume
major hormones controlling renal sodium chloride. ( Na+ and CI- )
Angiotensin II ; stimulates release of aldosterone
Aldosterone : Increase sodium reabsorption
Atrial Natriuretic peptide: Greater glomerular filtration rate and greater loss of sodium chloride in water
Major hormone regulating water loss is Antidiuretic hormone (ADH)
Water intoxication
Occurs when excess body water causes cells to swell dangerously
Occurs when a person consumes water faster then the kidneys can excrete it
Ions formed when Electrolytes disassociate and dissolve
Control osmosis of water between fluid compartments
Help maintain the acid-base balance
Carry electrical current
Serve cofactors
What has different concentrations of electrolytes and protien ions
Blood plasma= contains many protien ions , Interstitial fluid= contain few protien ions and intracellular fluid
Concentration of ions is expressed in units
milliequivalent per liter
( mEq/liter )
Sodium Electrolyte
Most important cation in extracellular fluid
Used for impulse transmission, muscle contraction, fluid and electrolyte balance
Chloride Electrolyte
Most important anion in extracellular fluids
Helps regulate osmotic pressure between compartments
Forms HCI in the stomach
Regulates CI- balance controlled by aldosterone
Potassium Electrolyte
Most important cation in Intracellular fluid
Involved in fluid volume, impulse conduction, muscle contraction and regulating pH
Aldosterone regulates plasma level
Bicarbonate Electrolyte
Second most common anion in intracellular fluid
Major member of the plasma acid-base buffer system, most important buffer system
Kidneys reabsorb or secrete it for final acid-base balance
Calcium Electrolyte
Most abundant ion in the body
Mostly concentrated in extracellular then in intracellular, always moving inward into the cell
structural component of bones and teeth
Used for blood coagulation, neurotransmitters release, muscle tone, excitability of nerves and muscles
Level in plasma regulated by parathyroid hormone
Phosphate Electrolyte
Very common anion common in the buffering system, intrecelluarly
Occurs as calcium phosphate salt
Regulated by parathyroid hormone and calcitriol
Magnesium Electrolyte
Most common in intracellular fluids
so an intercellular cation
Activates enzymes involved in carbohydrate and protien metabolism
Used in myocardial function, transmission in the CNS and operation of the sodium pump
pH of arterial blood
Ranges form 7.35 to 7.45 Maintained by several mechanisms -buffer systems -exhalation of carbon dioxide -kidney excretion of H+
Buffer system includes
Protien buffer system: most abundant in intracellular fluid and blood plasma.
Sodium causes
136- 148
Hyponatremia: low sodium Hypernatremia: increased sodium or dehydration
Potassium causes
3.5-5.0
Hypokalemia:excess loss & Hyperkalemia: excessive potassium intake
Calcium causes
9.0 -10.5 mg/l
Hypocalcemia: & Hypercalcemia
When pH rise and falls in protien buffer system
Rises, COOH group disassociates to act like an acid
falls: The free amino group acid disassociates to act like a base
Hemoglobin
RBC acts as a buffer
Carbonic acid-bicarbonate buffer system
Based on the bicarbonate ion which acts as a weak base, and carbonic acid which acts as a weak base
If pH rises and falls in carbonic acid bicarbonate buffer system
falls; the HCO3- removes excess H+
rises: H2CO3 can provide H+
Phosphate buffer system
Between dishydrogen phosphate and mono hydrogen phosphate systems
important within cell
Exhalation of carbon dioxide
CO2 mixes with water in the blood to form carbonic acid.
Leads to less acid production and rise in pH
with increased exhalation of CO2 pH rises, decreases, pH falls
Kidney secretion of H+
removes nonvolatile acids.
Proximal convoluted tubules and collecting ducts of the kidneys secrete H+ into the tubular fluid, removing it from the blood
Acidosis
blood pH is below 7.351
Alkalosis
blood pH is above 7.45
Respiratory acidosos
blood pH drops due to excessive retention go CO2 leading to excess H2CO3
Respiratory alkalosis
blood pH rises due to excessive loss of CO2, hyperventilation
Metabolic acidosis
Too much acid in blood
Arterial blood levels of HCO3( bicarb) falls
Metabolic Alkalosis
Arterial blood levels of HCO3 rises
Dehydration and hypernatremia
Inadequate fluid intake, loss of more water than Na+
Hypokalemia
chronic use of laxatives, drugs that cause K+ loss
