chapter 17 fluid and electrolytes Flashcards
two-thirds of the total volume of water, found within individual cells
intracellular fluid
remaining third of the total volume of water?
extracellular fluid
Includes: tissue fluid, blood plasma and specialized fluids
What are the two ways that water moves?
filtration and osmosis
process of filtration in capillaries?
plasma is forced out into tissue spaces (another compartment) and then is called tissue fluid
process of osmosis in cells?
water will move through cell membranes from the area of greater concentration to the area of lesser concentration.
Where does most of the water that the body requires come from?
ingestion of liquids
1600 ml per day
The daily water total from food
700 ml per day
what is the last source of water?
metabolic water-product of cell respiration
200 ml per day
total intake of water per day?
2500 ml or 2.5 liters
Where does most of the water loss from the body come from?
urine
1500 ml per day
total output of water?
2500 ml per day
How much water is lost in sweat?
500 ml per day
how much water is lost in exhaled air (vapor)?
300 ml per day
how much water is lost in feces?
200 ml per day
What is osmoreceptors?
detect changes in the osmolarity of body fluids
What is osmalarity
the concentration of dissolved materials present in a fluid
less fluid-higher osmolarity
more fluid- lower osmolarity
dehydration= higher osmolarity in blood
How is the hypothalamus involved in water balance?
because of its production of antidiuretic hormone (ADH)
What is ADH( Anti-diuretic hormone) and how does it regulate water?
from the posterior pituitary gland, it increases the re absorption of water by the kidney tubules
which returns to the blood to preserve volume and urinary output decreases
What is Aldosterone and how does it regulate water?
increases the re absorption of Na+ ions by the kidney tubules
water from the renal filtrate follows Na+ ions back to the blood
When is Aldosterone secreted?
when the Na+ ion concentration of the blood decreases or whenever there is a significant decrease in blood pressure
What are other factors that contribute to water loss?
Excessive sweating, hemorrhage, diarrhea or vomiting, severe burns and fever
What is water intoxication?
osmolarity of blood decreases caused by overconsumption of fluids and there is too much water in proportion to electrolytes
side effects: dizziness, abdominal cramps, nausea and lethargy
Which hormone helps excrete the excess water of the kidneys?
Atrial natriuretic peptide
which is secreted by the atria when blood volume or blood pressure increases
How does ANP contribute to water regulation?
it decreases the re absorption of Na+ ions by the kidneys
which increases urinary output of sodium and water
also ADH will diminish during this process
What are electrolytes?
chemicals thar dissolve in water and dissociate into their positive and negative ions
What are your positive ions (cations)?
Na+ (sodium)
K+ (potassium)
ca2+ (calcium)
mg2+(magnesium)
fe2+ (Iron)
h+ (hydrogen)
What are your negative ions (anions)?
Cl- (chloride)
HCO3- (bicarbonate)
SO4 (sulfate)
HPO4 (phosphate)
and protein anions
How does Aldosterone regulate the concentration of electrolytes?
increases the reabsorption of Na+ ions and the excretions of k+ ions by the kidneys
How does ANP regulate the concentration of electrolytes?
increases the excretion of na+ ions by the kidneys and lowers the blood sodium level
which hormones regulate the blood levels of calcium and phosphate?
Parathyroid hormone (PTH) and calcitonin
PTH increases reabsorption of these calcium and phosphate from bones to blood and by small intestine
calcitonin promotes the removal of calcium and phosphate from the blood to the bones
What is the most abundant cation and anion in ECF?
sodium (na+) cation
Chloride (Cl-) anion
what is the most abundant cation and anion in ICF?
K+ (potassium) cation
HPO4 (phosphate) anion
Sodium (na+)
creates much of the osmotic pressure of ECF
essential for electrical activity of neurons and muscle cells
Potassium (K+)
creates most of osmotic pressure in ICF
essential for electrical activity of neurons and muscle cells
Calcium (Ca+2)
98% found in bones and teeth
maintains excitability of neurons and muscle cells
essential for blood clotting
Magnesium (mg+2)
50% found in bone
more abundant in ICF than in ECF
essential for ATP production and activity of neurons and muscle cells
Chloride (Cl-)
Diffuses easily in and out of cells
helps regulate osmotic pressure
Part of HCl in gastric juice
Bicarbonate (HCO3)
part of the bicarbonate buffer system
Phosphate (HPO4 -2)
85% found in bones and teeth
primarily an ICF anion
part of dna, rna, atp phospholipids
part of phosphate buffer system
Sulfate (so4 -2)
part of some amino acids and proteins
Normal ph of blood?
7.35-7.45
intracellular fluid ph
6.8-7.0
What is a buffer system?
is to prevent drastic changes in PH of body fluids by chemically reacting with strong acids or bases that would change the PH
consist of a weak acid and a weak base
Bicarbonate buffer system
most important buffer system to keep blood ph from changing
two components = carbonic acid (weak acid) and sodium bicarbonate (weak base)
strong acid reacts with sodium bicarbonate to produce salt and a weak acid
strong base reacts with carbonic acid to produce water and a weak base
important in both the blood and tissue fluid
Phosphate buffer system
2 components= sodium dihydrogen phosphate (weak acid) and sodium monohydrogen phosphate (weak base)
same as bicarbonate except phosphate is used
important in the regulation of the ph of blood by the kidneys
protein buffer system
Most important one for intracellular fluids
carboxyl group may act as an acid because it can donate a hydrogen ion
amine group may act as a base because it can pick up hydrogen ion
how does the respiratory system affect PH?
it regulates the amount of CO2 present in body fluids
What is respiratory acidosis?
decrease rate or efficiency of respiration
ex:Asthma, emphysema, pneumonia, paralysis of respiratory muscles
compensation: kidneys excrete H+ ions and reabsorb Na+ ions and HCO3 - ions
What is respiratory alkalosis?
increased rate of respiration
ex: anxiety, high altitude
compensation: Kidneys retain h+ ions and excrete na+ ions and HCO3- ions
what is metabolic acidosis?
caused by kidney disease, ketosis, diarrhea or vomiting
compensation: increased respiration to exhale CO2 to decrease H+ ions formation to raise PH to normal range
What is metabolic Alkalosis?
caused by over ingestion of bicarbonate medications, gastric suctioning
compensation: decreases respirations to retain CO2 which increases formation of H+ ions to lower PH to normal range
How do kidneys help regulate the Ph of extracellular fluid?
excreting or conserving H+ ions and by reabsorbing (or not) Na+ ions and HCO3 - ions
Why are the renal mechanisms important?
Kidneys have the greatest capacity to buffer an ongoing Ph change
takes longer to get working than respiratory compensation but lasts longer than respiratory mechanisms
What are the effects of Acidosis?
detrimental to the central nervous system, causing confusion, disorientation and coma
What are the effects of alkalosis?
affects both the CNS and PNS causing irritability and muscle twitches, which can lead to severe muscle spams and convulsions
