Renal system Flashcards
what are the conditions in the internal environment controlled by the kidneys
concentration of waste products
concentration of ions
pH
volume and pressure
what are the functions of the renal system
regulates water homeostasis
regulates ECF volume
regulates concentration of most ECF ions
excretes waste products
regulates pH by adjusting urinary acid excretion
produces and activates hormones
how does the kidney react to hypoxia conditions
as blood carries RBC to kidneys, low O2 levels detected by Hif-alpha subunit > combines with Tif-beta to form hypoxia response element > produce erythropoietin > stimulate RBC production in bone marrow > increase O2 carrying capacity
structure of aquaporin 1
6 transmembrane domains
exists as tetramer with each subunit having its own water pore
what are the defence mechanisms against changes in ECF [H+]
buffer system: reversible reaction between HCO3- and H+
respiratory control: controlling concentration of CO2 in the blood > in turn control [H+]
renal control: regulate pH by excreting excess H+ and reabsorbing bicarbonate ions
how to find plasma clearance rate of a substance
(urine conc of a substance x urine flow rate) / plasma conc of a substance
commonly used substances for plasma clearance test
inulin, creatine, para-aminohippuric acid
causes of kidney failure
high blood pressure and diabetes
infection, toxic substances, autoimmune response
urinary tract obstruction
types of kidney failure
acute: rapid loss of renal function, condition may be reversible
chronic: progression in disease of kidneys; gradual loss in renal function; condition is not reversible
major consequences of renal failure
uremia: accumulation of waste products
salt and water retention
metabolic acidosis
anemia
endocrine disorder
disorder of mineral metabolism
difference between cortical and juxtamedullary nephrons
glomeruli of cortical lie in outer layer of cortex, while that of juxtamedullary lie on inner layer
loop of henle of cortical dip slightly into medulla while that of juxtamedullary plunges entirely through medulla
peritubular capillaries of juxtamedullary forms vasa recta, but not for cortical
what are the 3 basic renal processes
glomerular filtration > tubular reabsorption > tubular secretion
what is the pathway of substances to be filtered
pores between and fenestrations within endolethial cells of glomerular capillary > acellular basement membrane > filtration slits between the foot processes of podocytes in inner layer of Bowman’s capsule
what are the forces involved in glomerular filtration
glomerular capillary blood pressure (55): pressure exerted by blood within glomerular capillaries
plasma-colloid osmotic pressure (30): since plasma proteins cannot be filtered > conc of H2O in bowman’s capsule greater than glomerular capillaries > osmosis down concentration gradient > opposes filtration
bowman’s capsule hydrostatic pressure (15): pressure exerted by fluid in bowman’s capsule against glomerular capillaries
what are the mechanisms regulating GFR
auto regulation: prevent spontaneous changes in GFR
extrinsic sympathetic control: aimed at long term regulation of arterial blood pressure