Fluid, Electrolyte, Acid-Base Balance Flashcards
What is respiratory acidosis?
Ventilation fails to keep up with CO2 production
-results in lowered pH
What is renal compensation?
—adjustment of pH by changingrate of H+ secretion by renal tubules
What is a physiological buffer?
a system that controls output of acids, bases, or CO2
What are the two protein side groups involved in protein buffering? what of the functions of each group?
- Carboxyl (-COOH) releases H+
- (-NH2) side groups bind to H+
The pH of a solution is determined solely by___
the amount of hydrogen ions
How is Calcium homeostasis regulated?
By PTH, Calcitriol, and calcitonin(in children)
-cause bone deposition and resorption also intestinal absorption and excretion
What are the stimuli for aldosterone secretion?
- Hyponatremia
- Hyperkalemia
- hypotension
What is dehydration? What can cause it?
- More water than sodium is lost
- ECF osmolarity rises
- caused by lack of drinking water, diabetes, ADH hyposecretion, sweating, diuretics
why do cells maintain very low intracellular Ca2+ levels
-to prevent Calcium phosphate precipitation
What are the two main physiological buffers in the body?
The urinary system
the Respiratory system
What is the Bicarbonate buffer formula?
CO2 + H2OH2CO3 HCO3− + H+
What gives proteins the ability to buffer?
the side groups of their amino acid residues
Homeostatic balances are maintained by the collective action of what 8 body systems?
- Urinary
- Respiratory
- Digestive
- Integumentary
- Endocrine
- nervous
- cardiovascular
- lymphatic
What is a buffer?
any mechanism that resists changes to pH
The most abundant solute particles in the body are?
Electrolytes
What are the side effects of fluid excess?
Pulmonary and cerebral edema and death
What are the two major fluid compartments in the body? what % of fluid is within them?
- Intracellular Fluid 65%
- Extracellular fluid 35%
How does ADH decrease blood osmolarity?
By stimulating the renal collecting duct to reabsorb more water this causes a drop in blood osmolarity as H2O is increased
How does the phosphate system neutralize acid in the urinary system
H+ ions from the blood are sent into the tubular fluid and phosphates react with H+ and switch it with Na2
____ governs fluid intake
Thirst
Which system neutralizes the most acid or base? why?
the urinary system because it actually expels the H+ other systems only reduce concentration
What role do the kidneys play in the bicarbonate buffer system?
They excrete Bicarb to lower ph and excrete H+ to raise pH
What is short term thirst inhibition?
Inhibition caused by:
- cooling of the mouth
- Distension of stomach and small intestines
- only lasts 30-45 minutes
- prevents over drinking
What are the three homeostatic balance systems in the body?
- Fluid balance
- Electrolyte Balance
- Acid-Base Balance
how does progesteroneeffect sodium levels?
Reduces Na+ reabsorption
What is sensible water loss?
Observable loss such as urine, feces, and sweat
What is the most significant solute in determining total body water and distribution of water amoung fluid compartments?
Sodium
Bases are defined as
Any chemical that accepts H+
What are the three types of water loss?
- Sensible
- Insensible
- Obligatory
Water moves by ___
osmosis
What are the major cations of ECF?
- Na+, Ca2+
What are the two types of Hyperkalemia and what are their effects?
- Quick onset from crush injury: makes nerves and muscles abnormally excitable
- Slow onset: inactivates voltage-regulated Na+ channels, nerves and muscles become less excitable
What are some functions of Phosphates?
- Components of Nucleic acids, phospholipids, ATP, GTP, cAMP, and creatine phosphate
- Act as buffers
- activates metabolic pathways by phosphorylating enzymes and substrates
What is the main function of Mg2+?
Serves as a cofactor for enzymes, transporters, and nucleic acids
What is preformed water?
Water that is eater or drunk
What is metabolic alkalosis?
High pH from overuse of bicarb. or loss of stomach acid
The most dangerous types of electrolyte imbalances are___
Potassium imbalances
What is fluid deficiency?
When fluid output exceeds intake
What is Volume depletion? what can cause it?
- Proportionate amounts of water and sodium are lost
- Total body water decline
- Caused by bleeding, vomiting, diarrhea, burns, Addison disease
What are the two main side effects of dehydration and what do they trigger next?
- Reduced blood volume and pressue
- increased blood osmolarity
- Both work to trigger the hypothalamus
What are the causes and symptoms of hypercalcemia?
- Causes: alkalosis, hyperparathyroisium, hypothyroidism
- reduces membrane Na+ permeability, inhibits depolarization of nerve and muscle cells
- muscular weakness, depressed reflexes, cardiac arrhythmias
What is a chemical buffer system?
Mixtures composed of weak acids and weak bases that are able to restore pH in fractions of seonds
What are the causes and symptoms of Hyponatremia?
- large volumes of sweat and urine are lost
- sodium not replaced
- reduced urine volume as a result
How does dehydration effect water output?
It causes output to slow due to the action of ADH
What are the forms of phosphates found in the body
Labled as Pi collectivley
- Phosphate(PO4-3)
- Monohydrogen Phosphate (HPO4-2)
- Dihydrogen Phosphate(H2PO4-)
What is the difference between a strong aid and a weak acid?
Stong acid ionize freely weak acids only sightly ionize
Water output is controlled by ____
Variation in urine volume
What is the phosphate buffer system?
a solution of monohydrogen phosphate and dihydrogen phosphate
How is Chloride homeostasis achieved?
It is closley related to Na+ aka salt is both Na+ and Cl-
When Ca2+ in within cells how is it managed?
It is kept inactive in the Smooth ER
What is respiratory compensation?
—changes in pulmonary ventilation to correct changes in pH of body fluids by
expelling or retaining CO2
What are the two categories of acid-base imbalance?
Respiratory and metabolic
What are the major electrolytes of ECF?
Sodium salts
What is a compensated metabolic imbalance?
When the kidneys compensate for pH imbalances of respiratory system or the respratory system compensates for pH imbalances of the kidneys
What are the three types of extracellular fluid and their respective % of total body water?
- Plasma and Lymphatic fluid 8%
- Interstitial fluid 25%
- trans-cellular fluid 2%
What are the two types of fluid excess disorders?
- Volume excess
- Hypotonic hydration
A majority of the chemical buffering done in the body is carried out by the ___
protein buffer system 3/4th of buffering
Sodium concentration is coordinated by?
Aldosterone”salt retaining hormone”
What is the major electrolyte of ICF?
Potassium salts
How does aldosterone cause sodium retention?
- Binds to nuclear receptors
- Activates transcription genes for sodium-potassium pump
- Causes tubules to reabsorb more sodium and secrete more potassium
- water and chloride passively follow
What is the major anion in ECF?
Cl-
How does Parathyroid hormone effect phosphate levels?
- By increasing the excretion of phosphate
- Calcium and phosphate bind together so with less phosphate available more calcium becomes available
What is long term thirst inhibition?
Inhibition due to:
- Absorption of water to reduce osmolarity
- requires 30+ minutes
How does ammonia act to neutralize acids in tubular fluid?
By combinding with H+ and Cl- to form ammonium chlorideweak acid
How do Natriuretic peptides effect sodium reabsorption?
-They inhibit sodium reabsorption as well as renin and ADH secretion
-causes the elimination of more Na+ and water thus lowering BP
-
What occurs in the hypothalamus once it is triggered by dehydration?
- Osmoreceotirs respond to angiotensis II from low BP and to the low osmolarity of ECF
- Produces and releases ADH
- C. cortex causes thirst
- Salivation is innhibited
What is the Bicarbonate buffer system?
A solution of carbonic acid and bicarbonate ions
What is the major anion in ICF?
PO4 -3
Osmosis from one fluid compartment to another is determined by _________ of each compartment
Relative concentrations of solutes
Sodium salts account for _____ of osmolarity in ECF
90-95%
How do glucocorticoids effect sodium level?
Promotes Na+ reabsorption
How does Estrogen effect sodium levels?
Estrogen mimics aldosterone
How does excessive sweating cause dehydration?
- Sweat is lost
- sweat gland produce more sweat
- Loss of fluid cause rise in osmolarity and drop in pressure and volume
- Blood reabsorbs tissue fluid to compensate
- ICF diffuses out to replace lost tissue fluid
What is metabolic water?
Water that is a byproduct of aerobic metabolism
What is Hypotonic hydration?
- AKA water intoxication/positive fluid balance
- More water than Na+ retained or ingested
- ECF becomes hypotonic
- Causes cellular swelling
What are the major cations of ICF?
K+ and Mg+
Explain the process of H+ secretion and neutralization in the kidneys
- Carbonic acid in the blood disassociates into CO2 and H2O then cross into tubule cell to reform into carbonic acid
- Carbonic acid moves to next cell where it ionizes once more
- H+ is sent out and Na+ from disassociated sodium bicarb(from filtrate) is taken in and sent to blood
- H+ binds with HCO3 from the remainder of the sodium bicarb. which reforms carbonic acid
- Carbonic acid is then separated by the CAH in the brush border of the tubule cell into H20 and CO2
- The CO2 is reabsorbed and the H2O) is excreted
What are the two types of thirst inhibition?
Short-term and long-term
Water gain comes fro what two sources?
- Preformed water
- Metabolic water
What is respiratory alkalosis
raised pH from hyperventilation
What are some causes and symptoms of Hypocalcemia?
- Causes: Vitamin D Deficiency, diarrhea, pregnancy, acidosis, hypoparathyroidism, hyperthyroidism
- Increases membrane Na+ permeability, causes nervous and muscular systems to become excitable
- results in tetany, laryngospasms, death
What does aldosterone target?
-receptors in the ascending nephron loop, the DCT, and the cortical part of the collecting duct
What do chloride imbalances result in?
a disturbance in acid base balance
Acids are defined as
Any chemical that releases H+
What are the causes and symptoms of Hypernatremia?
- excess IV saline
- Causes water retention, hypertention, and edema
What are the three major chemical buffers?
- Bicarbonate
- Phosphate
- Protein systems
What is metabolic acidosis?
-increased production of organic acids, ingestion of acidic drugs, or loss of base from diarrhea
What is obligatory water loss?
Output that is realtivley unavoidable such as expired air, cutaneous transpiration, sweat, fecal moisture, and minimum urine output
What is a chemical buffer?
a substance that binds to H+ and removes from solution or releases H+ into solution
How does alkalosis effect cells?
H+ diffused out of cells causing K+ to diffuse into cells
-This causes depolarization and over stimulation leading to spasms and death
How is Potassium homeostasis achieved?
Linked to Na+
What is insensible water loss?
unnoticed water loss such as expired breath and cutaneous transpiration
Sodium homeostasis is achieved by ___
regulating salt intake
Where is the phosphate buffer system used the most?
in the ICF and renal tubles
How does acidosis effect the cells?
H+ diffuses into cells and drives out K+ causing an elevation of K+ in the ECF
-elevated K+ causes membrane hyperpolarization and resulting effects
What is the equation for the phosphate buffer system?
H2PO4− HPO4 2− + H+
What are the causes and symptoms of Hypokalemia?
caused by sweating, chronic vomiting, diarrhea, aldosterone hyposecretion, alkalosis
-Makes nerves and muscles less excitable
What is volume excess?
- Retention of H2O and Na+
- ECF remains isotonic
- Caused by aldosterone hypersecretion or renal failure
What is a uncompensated pH imbalance
When the body cannot correct the imbalance without intervention
54% of magnesium is in the ___ and the rest is in ___
- Bone
- ICF
What is the protein that binds to Ca2+ to keep it inactive
Calsequestrin
What is the normal pH range of blood and tissue fluid?
- 4
7. 35-7.45
What is fluid excess?
A disorder of fluid balance where you begin to retain water
What is the minimum urine output?
400mL/Day
What are the two type of fluid deficiency?
- Volume depletion
- Dehydration
