properties of blood and homeostasis Flashcards
total H20 in body?
40L
% water by volume women?
%52
% water by volume men?
%63
intracellular compartment (3)
found inside cells
%63 by volume
-higher in K+ (potassium)
extracellular compartment (3)
found outside of cells
%37 by volume
-higher in Na+
transcellular fluid
membranes
fluids found within body cavities lined with special epithelia
hydrostatic pressure
results from fluid volume and force
osmotic pressure
pressure resulting from unequal amount of dissolved solutes which cannot cross a semipermeable membrane
osmosis
diffusion of water
thirst mechanism results from?
rising osmotic pressure of extracellular fluids, primarily CSF
inhibitor of thirst mechanism
act of drinking and resulting distension of stomach wall both serve to inhibit the thirst mechanism (negative feedback)
what is primary means of regulating H2O balance
urine formation (in moderate environment)
regulation of water output/loss
membranes of distal convoluted tubules/collecting ducts remain impermeable to water, leading to urine formation unless posterior pituitary hormone secretes ADH, causing nephrons to reabsorb H20
what does ADH cause nephrons to do?
reabsorb H20
electrolyte intake/gain (3)
- achieved by healthy eating & drinking
- response to thirst mechanism provides motivation
- some furnished through metabolic processes
electrolyte loss is result of?
occurs through normal perspiration/fecal elimination
regulation of electrolytes is achieved by…
the kidneys through influx of various hormones
aldosterone (4)
- primary regulator of Na+
- inversely regulates K+
- causes increase in Na+ reabsorption*
- causes increase in K+ secretion*
parathyroid hormone
secretion of PTH causes increase in blood Ca2+ concentration
calcitonin
released by thyroid hormone in response to high Ca2+ concentration
what is normal blood PH
7.35-7.45 slightly alkaline
acids/bases
acids: liberators of hydrogen
bases: retainers of hydrogen
explain acid/base strength
electrolytes that ionize more completely (acids) or electrolytes that combine more readily (bases) are termed strong
3 regulations of hydrogen ion concentrations (3)
- acid base buffer
- respiratory center
- kidneys
acidosis
blood PH LESS than 7.35
alkalosis
blood PH greater than 7.45
acid buffer base system (2)
- bodies first response against PH changes
- chemicals that readily combine with acids/bases (when in excess) to maintain blood PH
respiratory center
- secondary defense to PH due to slow response (several minutes)
- increases rate/depth of breathing
kidney function
-secondary defense to PH due to slow response (1-3 days)
dehydration
condition in which water loss is greater than water gain (output exceeds intake)
diuretic
any substance that increases urinary output
electrolyte
inorganic compound/molecule that dissociates in water and releases ions into the solution.
RESPIRATORY ACIDOSIS result of
cause: accumulation of CO2
- decreased rate/depth of breath, obstruction of airway, decreased gas exchange
METABOLIC ACIDOSIS result of
cause: accumulation of non-respiratory acids
- kidney failure to excrete acids, excessive production of keto acids as in diabetes mellitus
RESPIRATORY ALKALOSIS result of
cause: excessive loss of CO2
- Hyperventilation from fever, poisoning, altitude, anxiety
METABOLIC ALKALOSIS result of
cause: loss of non respiratory acids
- gastric drainage, vomiting with loss of gastric secretions
