Renal Function

What is known as the bowman’s capsule?

the glomerulus

What is located in the cortex of the kidney?

proximal and distal convoluted tubules

What is composed of the the thin descending limb and the ascending limb?

loop of henle

What is formed by two or more convoluted tublues?

the collecting duct

What are the 3 basic renal processes?

glomerular filtration

tubular reabsorption

tubular secretion

What is filtered and secreted but not reabsorbed?

NH3

glucose

amino acids

NH3

What is filtered and a portion reabsorbed?

NH3

glucose

amino acids

glucose

What is filtered and completely reabsorbed?

amino acids

What filters incoming blood?

glomerular filtration

What are factors that facilitate filtration?

high pressure in the glomerular capillaries

semipermeable glomerular basement membrane

size of particles that influence what can filter through

How much is filtered out of the kidneys every minute?

1200-1500 mL

How is blood filtered per minute measured?

glomerular filtration rate GFR

How much of protein-free,cell-free fluid is filtered out in the glomerulus?

125-130 mL

What receives the cell and protein free filtrate and returns the valuable products back into circulation?

proximal convoluted tubule

What is tubular reabsorption?

the active process for when substances move from tubular lumen to the peritubular capillary plasma

What is tubular secretion?

describes the movement of substances from peritubular capillary plasma to the tubular lumen

describes when the tubule cells secrete products of their metabolism into the filtrate in the tubular lumen

What is the hairpin-like loop between proximal tubular and distal convoluted tubule?

loop of henle

What does the loop of henle maintain?

hyperosmolality that develops in the medulla

What makes small adjustments to achieve electrolyte and acid-base balance?

distal convoluted tubule

What is produced by the adrenal cortex and stimulates sodium reabsorption in the distal tubules and K and H ion secretion?

aldosterone

What is secreted by the posterior pituitary in response to increased blood osmolality, stimulates water reabsorption, and makes the distal collecting tubules permeable?

AVP

What is the final site for concentrating or diluting urine?

collecting duct

What acts on the collecting duct to control reabsorption of water and sodium?

AVP and aldosterone

What gets reabsorbed in the collecting duct?

Cl and urea

T/F: collecting ducts are highly permeable

true

What plays an important tole in maintaining osmolality of the renal medulla?

urea

What is the waste product formed due to degradative metabolism of nucleic acids, amino acids, and proteins?

nonprotein nitrogen compounds (NPNs)

What can be synthesized outside the liver and is converted from ammonia to avoid toxicity?

urea

What is the first source of muscle fuel?

creatinine

What is the primary waste product of purine metabolism and is readily filtered by the glomerulus?

uric acid

What regulates water loss or conservation?

AVP

What happens to the renal tubules in dehydration?

reabsorb water at their maximum rate

What happens where there is excess water in the system?

excretion of large amounts of diluted urine

What is the primary extracellular cation and is controlled only by excretion?

sodium

What is the main intracellular cation, competes with H ions in exchange for Na, and is filtered by glomerulus and reabsorbed?

potassium

What is the principle extracellular anion that is involved in maintenance of extracellular fluid balance and is passively reabsorbed with Na?

chloride

What is in higher concentrations in intracellular fluid than extracellular fluid, is protein or non-protein bound, and is homeostatically controlled by PTH?

phosphate

What is the 2nd most predominant intracellular cation, can be protein and non-protein bound, and the ionized version is filtered freely?

calcium

What is the major intracellular cation that is an enzyme cofactor and the ionized form is filtered and reabsorbed?

magnesium

What is the initial component of RAAS that is produced by the renal medulla and catalyzes synthesis of angiotensin?

renin

What acts on erythroid progenitor cells in bone marrow?

erythropoietin

Chronic renal insufficiency of what is often associated with osteomalacia?

1,25-dihydroxyvitamin D

What is produced by the kidneys to increase renal blood flow, sodium and water excretion, and renin release?

prostaglandins

Creatinine clearance equation

(UCR/PCR) x (VUR/mins) x (1.73/A)

What does the national kidney foundation recommend eGFR be reported with?

serum creatinine level

What was one of the 1st formulas to predict GFR but did not correct for body surface area?

Cockcroft-gault formula

What modifications have been made in the diet of renal disease?

takes into consideration body surface area

underestimates GFR in healthy

overestimates GFR in underwieght

What was made in 2009 to create a more accurate formula with less weight bias?

CKD-EPI

What can be creatinine only or include cystatin C?

CKD-EPI 2021 equation

What is a low MW protein that has a steady state production by most tissues and is freely filtered by glomerulus, reabsorbed, and catabolized by the proximal tubule?

cystatin C

What rises faster than creatinine in AKI?

cystatin C

What is biologic variation?

random fluctuation around a hemostatic setting point

Within subject bv is for:

single individuals

Between subject bv is for:

multiple individuals

What bv is seen in creatinine?

within subject is less than the between subject

What is the bv with cystatic C?

between subject must smaller than within

What is a small, non-glycosylated peptide on the surface of most cells?

B2-microglobulin

Elevation of what indicates organ rejection?

B2-microglobulin

What is a low MW protein that is a nephrotoxin and is associated with acute skeletal and cardiac muscle injury?

myoglobin

What is the function of myoglobin?

bind and transport oxygen from the plasma membrane to the mitochondria of muscle cells

What happens when myoglobin release from skeletal muscle is sufficient to overload the proximal tubules and causes acute renal failure?

rhabdomylosis

What describes the presence of albumin in the urine and an important aspect for DM?

albuminuria

Why so albuminuria occur?

because of glomerulosclerosis which increases glomerular permeability

What is a 25-kDa protein expressed by neutrophils and epithelial cells including those in the proximal tubule?

Neutrophil Gelatinase-Associated Lipocalin

What is the first FDA-cleared test used to determine if critically ill patients are at risk of developing moderate to severe AKI in the next 12 hours?

nephrocheck

What is considered an abnormal amount of RBCs?

>2 RBS/hpf

What is considered an abnormal amount of WBCs?

>5 WBS/hpf

What is a cast?

precipitated, cylindrical impression of the nephrons

What is a Tamm-horsfall cast?

mucoprotein from the ascending loop of henle

What is an RBC cast diagnostic for?

glomerular inflammation

What is a WBC cast diagnostic for?

inflammation of the nephrons

What is a waxy casts mean?

pathological, tubular inflammation or deterioration

What is a fatty cast?

abnormal lipid inclusions

What is a broad cast indicate?

severe renal stasis

What crystals are produced in acid pH?

calcium oxalate

amorph urates

uric acid

cholesterol

cystine

What crystals are made in alkaline pH?

amorph phosphates

calcium carbonate

triple phosphate

ammonium biurate

What are pathological crystals?

leucine

tyrosine

cystine

sulfonamides

cholesterol

What are glomerular diseases?

disorders or diseases that directly damage the renal glomeruli which may exhibit normal function for awhile

What has a rapid onset of hematuria and proteinuria?

acute glomerulonephritis

What levels are seen in acute glomerulonephritis?

decreased GFR

anemia

elevated BUN and serum creatinine

oliguria

Na and water retention

CHF

What is ofter seen with recent beta hemolytic streptococci infection?

acute glomerulonephritis

What can go undetected at first and only sees minor decreases in renal function, sight proteinuria and slight hematurie?

chronic glomerulonephritis

What causes nephrotic syndrome?

different diseases that result in injury and increased permeability of the glomerular basement membrane

What is seen in nephrotic syndrome?

massive proteinuria and hypoalbuminemia

hyperlipidemia and lipiduria

What is a result of tubular diseases?

decreased excretion or reabsorption of certain substances

reduced urinary concentrating capability

What type of RTA is it when the renal tubules are unable to keep up the pH gradient between blood and tubular fluid?

Distal RTA

What type of RTA is it when there is decreased bicarb reabsorption that results in hyperhcloremic acidosis?

proximal RTA

What is generally seen in RTA?

abnormally low serum values for phosphorus and uric acid

glucose and amino acids in urine

some proteinuria

What happens when there is a sudden, sharp decline in renal function due to acute toxic or hypoxic insult to kidneys?

acute kidney injury

What type of AKI has a defect in blood supply before the kidney, cardiovascular system failure and hypovolemia?

prerenal AKI

Acute tubular necrosis is the most common what?

intrinsic AKI

What AKI has a defect in post kidney urinary tract, lower urinary tract obstruction and rupture of the urinary bladder?

postrenal AKI

What happens to renal function in chronic kidney disease?

gradual decline over time

A GFR >90 indicates what stage of CKD?

stage 1

kidney damage with normal or increased GFR

A GFR of 60-89 indicates what stage of CKD?

stage 2

kidney damage with normal or decreased GFR

A GFR of 45-59 indicates what stage of CKD?

stage 3A

moderately decreased GFR

A GFR of 30-44 indicates what stage of CKD?

stage 3B

moderate to severely decreasd GFR

A GFR of 15-29 indicates what stage of CKD?

stage 4

severely decreased GFR

A GFR of <15 indicates what stage of CKD?

stage 5

kidney failure

What stage is end-stage renal disease with patients undergoing chronic dialysis?

5D