Water, Electrolyte and Acid-Base Balance

what happens if fluid is not kept in balance

cells and tissues break down or stop

what fluid is in the inside of cells

intracellular fluid

what fluid is in the outside of cells

extracellular fluid

what are the two things that allows water to move through compartments

cell plasma membranes and capillary walls

how does water move from digestive tract to blood capillaries

osmosis absorption

how does water move from blood capillaries to tissue fluid

filtration

how does water move from tissue fluid to lymphatic capillaries

osmosis reabsorption

how does water move from tissue fluid to cells

osmosis absorption

how much water do you typically gain and lose per day

2500ml

what are the two sources of water

metabolic and performed

how is water produced by metabolically

aerobic respiration

what are the four ways water is lost

urine

breath

sweat

cutaneous transpiration

how is cutaneous transpiration different from sweating

not glandular secretion

how does dehydration impact blood volume and pressure

decreases

how does dehydration impact solute concentration

increases

what receptors respond to the rise in osmolarity of blood during dehydration

osmoreceptors

what do osmoreceptors respond to during dehydration when BP drops

angiotensin II

what part of the brain produces antidiuretic hormone during dehydration

hypothalamus

what does antidiuretic hormone do

promotes water conservation

what part of the brain produces conscious sense of thirst

cerebral cortex

rehydration technique where water cools and dampens mouth

short-term inhibition of thirst

rehydration technique where water is absorbed from small intestines into blood

long-term inhibition of thirst

when does the conscious sense of thirst cease

ceasing of hypothalamic osmoreceptor response

what is affected if water and ions are reabsorbed back into body

fluid volume and composition

where do water and ions go if they are not reabsorbed

excreted in urine

what is a key ion that affects fluid balance

sodium

what are two elements that are needed to be absorbed or excreted together to maintain normal osmolarity of body fluids

water and sodium ions

what happens to blood osmolarity when sodium concentration increases

blood osmolarity increases

what causes dehydration

more water is excreted than sodium

what is the osmotic pressure level compared to fluid level during dehydration

hypertonic

what is it called when proportionate amounts of water and sodium are lost

volume depletion

what is the osmotic pressure level compared to fluid level during volume depletion

isotonic

what is it called when more water is reabsorbed than sodium

water intoxication

what is the osmotic pressure level compared to fluid level during water intoxication

hypotonic

what is volume depletion caused by

excessive diarrhea and severe burns

what is water intoxication caused by

losing large amount of water and sodium and replacing it with no electrolytes

what is the most abundant solutes in fluid balance

electrolytes

what is the function of electrolytes

govern water distribution and content

what are included in electrolytes

salts, acids and bases

what is the electrolyte concentration in the ICF if it is abundant in ECF

lower in ICF

what is the electrolyte concentration of sodium

high ECF, low ICF

what is the electrolyte concentration of potassium

low ECF, high ICF

what is the electrolyte concentration of chloride

high ECF, low ICF

what is the electrolyte concentration of calcium

low in ECF and ICF

what is the function of sodium as electrolyte

depolarization phase of action potential

what is the most significant electrolyte in determining water balance and distribution in body

sodium

what is the function of potassium as electrolyte

repolarization phase of action potential

what is the function of chloride as electrolyte

formation of stomach acid

what is the function of calcium as electrolyte

activation of muscle contraction

what is the salt-retaining hormone

aldosterone

what directly stimulates the adrenal cortex to secrete aldosterone

hyponatremia and hyperkalemia

what type of blood pressure stimulates aldosterone secretion

hypotension

where does aldosterone act in

nephron loop, DCT and collecting duct

what is the overall affect of aldosterone

decreased water volume and lower pH

what is the normal blood and tissue fluid pH range

7.35 to 7.45

what does all of metabolism depend on that is very sensitive to pH

enzymes

what acid comes from anaerobic fermentation

lactic acid

what acids come from fat catabolism

fatty acids and ketones

what acid comes from carbon dioxide

carbonic acid

how is pH level determened

by hydrogen ion concnetration

what does H+ stand for

hydrogen ion

which side of pH scale is basic

14

term for any chemical that releases H+ in solution

acids

term for any chemical that accepts H+ in solution

bases

substance system that removes or releases H+ depending on its concentration

chemical buffers

how are buffer systems able to bind or release H+

composed of weak acids and weak bases

which major chemical buffer system involves carbon dioxide and carbonic acid

bicarbonate buffer system

what happens to the bicarbonate buffer system when carbon dioxide increases

reaction pushed to right lowering pH

what happens to bicarbonate buffer system if carbon dioxide decreases

reaction pushed to left raising pH

which major chemical buffer system involves phosphate containing compounds

phosphate buffer system

what happens to phosphate buffer system when increasing H+ and moving to right

lower pH

what happens to phosphate buffer system when decreasing H+ and moving to left

raises pH

where is phosphate buffer systems important in

renal tubule

which major chemical buffer system accounts for 3/4 of all chemical buffering in body fluids

protein buffer system

how is protein buffering ability due to

side groups of amino acid residues

what does carboxyl (-COOH) do for protein buffer systems

side groups release H+ when pH increases

what does amino (-NH2) do for protein buffer systems

side groups bind H+ when pH decreases

what happens to hydrogen ions and pH when carbon dioxide levels are high in blood

H+ increases and pH decreases

which receptors stimulate increase in pulmonary ventilation

peripheral and central chemoreceptors

how does acidity levels in blood even out through respiratory control

hyperventilation, more carbon dioxide is expired

what happens to hydrogen ions and pH when carbon dioxide levels are low in blood

H+ decreases and pH increases

how does alkaline levels in blood even out through respiratory control

hypoventilation, less carbon dioxide expired

is the urinary or respiratory systems more efficient for neutralizing acid

urinary system

why is urinary system more efficient for balancing acid levels

direct effect by removing H+ ions

what part of urinary system secretes H+ and removes it from capillary fluid

renal tubules

what level of pH is considered acidosis

below 7.35

what level of pH is considered alkalosis

above 7.45

what is the main physiological effect of acidosis

hyperpolarization makes nerve and muscle stimulation difficult

what is the main physiological effect of alkalosis

nerves and muscles overstimulated

what levels of pH is considered fatal

below 6.8 and above 8

what occurs when rate of pulmonary ventilation does not keep up with rate of CO2 production

respiratory acidosis

where does respiratory acidosis occur

emphysema

what happens when the rate of pulmonary ventilation exceeds rate of CO2 production

respiratory alkalosis

what results from increased production of acids and the body loses base from body through diarrhea or laxative overuse

metabolic acidosis

what happens due to overuse of bicarbonates resulting in loss of stomach acid

metabolic alkalosis

Long-term inhibition of thirst is mainly associated with:

a decrease in blood osmolarity

Low blood pressure (hypotension) and low sodium levels (hyponatremia) promote the secretion of _____ from the adrenal cortex.

aldosterone

Which of the following is FALSE regarding dehydration?

there is a decrease in blood osmolarity

true or false: Blood plasma osmolarity is higher than intracellular fluid osmolarity.

false

true or false: Tissue (interstitial) fluid is part of the intracellular fluid (ICF).

false