Renal Flashcards
what is the major job of the kidney?
regulate comp of body fluids/remove metabolic waste to ensure homeostasis
what is the functional unit of kidney?
nephron
what is the glomerulus?
tuft of capillaries surrounded by special type of basement membrane
what happens in glomerulus?
filtration (water/small molecules <5000 daltons are filtered into Bowman’s capsule)
why is filtrate not = to urine?
cuz of reabsorption and secretion steps
some major kidney fxns?
fluid electrolyte balance, excretion of metabolic wastes, excretion of drugs/toxins, reg acid-base balance, role in reg BP, erythropoiesis, vit. D activation
Most Na filtered by kidney gets _____
reabsorbed
majority Na reabsorbed and not regulated called ____ and this happens in _____
basal; proximal tubule
portion of Na reabsorption that can be regulated happens in:
distal convoluted tubule (aldosterone regulated)
almost all K is reabsorbed in _____
proximal tubule
any K in urine is ____ in the distal tubules in exchange for Na
secreted
ex. of metabolic wastes?
urea, creatinine, uric acid
how can diet increase urea production? Where does urea come from?
amino acids (ammonia), high protein intake, stress state, low energy diet (first priority is protein/a.a. breakdown for gluconeogensis), protein of low biological value
Vitamin D activation -OH steps happen in:
kidney and liver
important screening/diagnostic tests
BP, urinalysis (random urine protein or albumin, urine osmolality), serum urea, serum electrolytes, radiological procedures, assessment of GFR
what is ACR?
urine albumin to creatinine ratio
what is PCR?
urine protein to creatinine ratio (^ when CKD)
what is GFR?
volume of fluid filtered from renal glomerular capillaries into Bowman’s space per unit time
assessment of GFR is currently done by: ____ + _____
serum creatinine + eGFR
what is creatinine?
breakdown product of phosphocreatine (high energy reserve) in muscle
what factors determine how much creatinine is in serum?
1) produced in amounts proportional to muscle mass (going into blood) 2) depends on GFR (going out of blood)
why not just use serum creatinine?
too many other factors like muscle mass, age, sex, ethnicity, etc.
2 examples of formulas for GFR?
cockroft Gault and MDRD
CKD is characterized by:
progressive decline in kidney fxn occuring over mths/years, irreversible but can slow progression, dialysis/transplants extend life in kidney failure
etiology of CKD
DM, uncontrolled hypertension (damaging blood vessels in kidney), glomerulonephritis (inflammation in glomeruli), vascular disease (atherosclerosis affecting arteries), polycystic disease (genetic), lupus erythematosus (arthritis)
pathophysiology of CKD:
gradual decrease in fxning nephrons, cause may initially adversely affect either glomeruli or tubules, fewer remainng functional nephrons try to compensate by ^ in size and fxn, eGFR gradually decreases
signs and symptoms of CKD?
early on may be polyuria or nocturia but becomes oliguria/anuria/dysuria, foamy urine that is tea coloured, fatigue, itching, anemia, swelling of hands and feet, shortness of breath, bad taste in mouth, cold intolerance, nausea/vomiting/anorexia due to uremia, CNS symptoms
what causes CNS symptoms?
untreated uremia (buildup of urea/other byproducts of protein metabolism)
as GFR decreases, serum Phosphate ____, serum Ca ____, secretion of PTH ____
increases; decreases; increases
secondary decrease in Ca absorption?
impaired renal hydroxylation of 25-OH cholecalciferol
contributors to renal osteodystrophy (bone pain and fractures) are:
acidosis, excess PTH, altered vit D metabolism
treatment for CKD:
control BP, detect microalbuminuria and treat with drug therapy, control HbA1c, cease smoking, reduce dyslipidemia, nutr care, dialysis, renal transplants
2 types of dialysis:
hemodialysis and peritoneal dialysis
this dialysis involves an artificial kidney machine or dialyzer to remove unwanted substances from blood stream (permanent access to bloodstream), there are diff forms of vascular access
hemodialysis
rates and amounts of fluid/waste products removed can be varied by using diff:
membranes, blood flow rates, dialysate concentration
v total blood volume causes:
hypothalamus stimlate release of antidiuretic hormone from posterior pit gland –> ^ water reabsorption
regulation of BP is through ____ system
renin-angiotensin
what is urine osmolality?
ability of kidney to concentrate or dilute urine
ideal nuclear medicine method marker?
endogenous, freely filtered, not secreted/reabsorbed, inexpensive to measure
approx eGFR for young adults is:
120-130 mL/min/1.73m^2
malnutrition potential begins at stage ___ of CKD
3
why add glucose in dialysate?
prevent hypoglycemia
excess fluid is removed in hemodialysis by ___
ultrafiltration
what is the peritoneum?
membrane that lines ab cavity and surrounds ab organs, forming sac
how does peritoneal dialysis work?
dialysate enters peritoneal space thru catheter penetrating ab wall –>clamped so fluid remains in peritoneum, drain after given amount of time
peritoneal dialysis relies on exchange with _____ in the ____
circulating plasma ; capillaries
peritoneal similar to hemodialysis principles except:
dialysate contains enough glucose to make it hypertonic relative to plasma, causing fluid to flow into peritoneal cavity