Urinary Flashcards
what is excretion?
separating wastes from body fluids and eliminating them
how does the respiratory system carry out excretion?
CO2, small amounts of other gases, and water
how does the integumentary system carry out excretion?
water, inorganic salts, lactic acid, urea in sweat
how does the digestive system carry out excretion?
water, salts, CO2, lipids, bile pigments, cholesterol and other metabolic waste
how does the urinary system carry out excretion?
many metabolic wastes, toxins, drugs, hormones, salts, H+, and water
what is metabolic waste?
waste produced by the body
how is urea formed?
proteins -> amino acids -> NH2 removed -> forms ammonia (NH3)
then the liver converts NH3 to urea
what is uric acid?
product of nucleic acid catabolism
what is creatinine?
produce of creatine phosphate catabolism.
what does glomerular filtration make?
creates plasmalike filtrate of blood
what is tubular reabsorption?
removes useful solutes from filtrates and returns them to the blood
what is tubular secretion?
removes waste from blood and adds them to filtrate
how does water conservation occur?
the renal tubule removes water from the urine and returns it to the blood.
what are the three barriers to fluid movement?
endothelial cell of glomerular capillary, basement membrane, and filtration slit.
what are the forces in glomerular filtration?
blood hydrostatic pressure, colloid osmotic pressure, and capsular pressure.
how is the glomerular filtration rate controlled?
by homeostatic mechanisms: renal autoregulation, sympathetic control, and hormonal control.
how does the kidney autoregulate?
by myogenic mechanisms (smooth muscles), and tubuloglomerular feedback
what does the PCT do?
reabsorbs ~65% of the glomerular filtrate
when is the transport maximum reached?
when the transporters are saturated
what is tubular secretion important for?
acid-base balance, waste removal, and clearance of drugs and contaminants
which hormones are the DCT and collecting duct regulated by?
aldosterone, atrial natriuretic peptide, antidiuretic hormone.
what is renal clearance?
volume of blood plasma from which a particular waste is completely removed in 1 min.
what is osmoregulation?
maintenance of nearly constant osmotic pressure in the body
what is isotonic?
two solutions with the same osmotic pressure
what is hyperosmotic?
one solution has greater osmotic pressure than another
what is hyposmotic?
one solution has lower osmotic pressure than another
how does water move through the body?
digestive tract -> bloodstream -> tissues -> lymph nodes -> bloodstream
what do osmoreceptors respond to?
rising osmolarity of the ECF, reduced blood pressure, and angiotensin II.
what is aldosterone?
makes the kidney retain salt (comes from adrenal cortex)
what does ADH respond to?
dehydration, loss of blood volume, and rising blood osmolarity.
what is hypovolemia?
volume depletion of water and sodium but osmolarity remains normal
which hormones regulate sodium?
aldosterone and ADH
