CM - RENAL FUNCTION

retroperitoneum

kidneys are located on the posterior abdominal wall in the are known as

1-1.5 million

each kidney contains approximately how many nephrons?

nephrons

functional units of kidneys

glomerulus

proximal convoluted tubule

distal convoluted tubule

descending & ascending loop of henle

collecting ducts

parts of nephrons

renal artery

supplies blood to the kidneys

1200 ml/mins

total renal blood flow

600-700ml/mins

renal plasma flow

cortical nephron

removes waste and reabsorps nutrients in the kidneys

juxtaglomerular nephrons

concetrates urine in the kidneys

hydrostatic pressure

type of pressure created by varying sizes of the arterioles

oncotic pressure

pressure cause by higher protein conc

albumin

protein that is a major contributor to oncotic pressure

renal artery

afferent arteriole

glomerulus

efferent arteriole

peritubular capillaries

vasa recta

renal vein

order of blood flow in the Nephrons

glomerulus

bowman's capsule

PCT

DLH

ALH

DCT

collecting ducts

renal calyses

ureter

bladder

urethra

order of urine formation

podocytes

intertwining foot processes in the kidneys are known as

shield of negativity

the ability of kidneys to repel molecules with negative charge

juxtaglomerular cells

secretes renin enzyme

afferent arteriole

juxtaglomerular cells are found in

macula densa

sensor of change in blood pressure within the glomerulus

distal convoluted tubule

macula densa is found in

renin-angiotensin-aldosterone system (RAAS)

system that responds to the changes in the blood pressure and regulates the changes

sodium

primary electrolyte affected when RAAS is activated

angiotensinogen

bloodborne substrate for renin enzyme

angiotensin I

product formed from enzymatic rxn of renin with angiotensinogen; inert form of angiotensin

angiotensin II

product formed from enzymatic rxn of ACE with angiotensin I, active form of angiotensin and a powerful vasoconstrictor that corrects renal blood flow

renin

acts as both hormone and enzyme

angiotensin converting enzyme

an enzyme that activates angiotensin I into angiotensin II

lungs

ACE is produced by what organ

clearance test

best indicator of overall glomerular fxn

inulin clearance

gold standard/reference method for clearance test known as a polymer of fructose

creatinine clearance test

most commonly used clearance test

creatinine

waste product of muscle metabolism

24 hrs urine

best specimen for clearance test

urea clearance test

earliest known clearance test

C= urine creatinine/plasma creatinine x volume of urine/24 hrs x 1.73/A

creatinine clearance test formula

improperly timed specimen

greatest source of error in clearance test

cystatin c

produced by all nucleated cells; marker for long-term monitorin of renal fxn

beta 2 microglobulin

dissociates from human leukocyte antigens (MHC class I); better marker of reduced renal tubular fxn; identify end-stage renal disease and early rejection of kidney transplant

GFR=173 x serum creatinine x age x 0.742 (if female) x 1.212 (if black/african-american)

eGFR MDRD formula

serum creatinine

ethnicity

age

sex

parameters in MDRD (4)

BUN

age

serum creatinine

ethnicity

serum albumin

sex

parameters of MDRD (6)

c= (140-age) x weight/72xS. x 0.85 (if female)

cockroft and gault formula

95% water

5% solutes

urine composition

active transport

mechanism of tubular reabsorption that requires energy and must be combined with carrier protein

passive transport

movement of substances from area of higher concentration into lower concentration

glucose, amino acids, salts, chloride urine

substance transported through active transport

proximal convoluted tubules

glucose, amino acid, and salts are reabsorps in the

ascending loop of henle

substance that reabsorps chloride

sodium

reabsorps PCT and DCT

PCT, ADH ALH

substance that reabsorbs water

water, urea, sodium

substance that reabsorbs water, urea, and sodium

renal threshold

plasma concentrate at which active transport stops

160-180 mg/dl

glucose renal threshold

110-130 mmol/l

sodium renal threshold

DLH & ALH

renal concetrates begins at

osmosis

water is removed in the DCT through

sodium & chloride

reabsorbs in the ALS

osmolality

movement of water across semipermeable membbrane

anti-diuretic hormone

hormone responsible for renal concentrates

osmolality

measures only the number of particles

1-3:1

normal urine to serum ratio

freezing point depression

first principle in clinical osmometers

vapor pressure osmometers

principle of the dew point or temperature at which vapor condences to a liquid

>800m0m

urine: serum ratio: 3:1

neurogenic DI

<400 mOsm

urine:serum ratio: 1:1

specific gravity

measures number and sizes of particles

fishberg

patients deprived of 24 hrs

mosenthal

compare volume and specific gravity of day and night samples

free water clearance

use to determine the ability of the kidney to respond to the state of body hydration

osmolar clearance

indicates how much water must be cleared each minute to produce a urine with the same osmolality as the plasma

same plasm

urine osmolality x urine volume/plasma osmolality

osmolar clearance formula

osmolar clearance - urine volume

free water clearance formula

renal tubular acidosis

condition where the kidney is unable to produce an acid urine

PAH (para amino hippuric acid) test

most commonly used test for renal secretion

PSP (phenolsulfonphthalein) dye excretion test

obsolete test for renal secretion