AUBF [LEC] - Renal Functions Flashcards
functional unit of the kidney
nephron
4 main components of the urinary system
Kidney
Ureters
Bladder
Urethra
where blood would be filtered, then the filtrate flows to the ureter
kidney
if this fills, you will feel the urge to urinate
bladder
directs it towards the external orifice of the genitalia
urethra
smallest part of the kidney that can perform all these functions
nephron
how many nephrons per kidney
1-1.5 million
2 types of nephron and their percentage
cortical (85%)
Juxtamedullary (15%)
tuft of capillaries that will allow the unwanted substances to be removed
glomerular filtration
100% reabsorbed by the renal tubules to maintain blood pH
bicarbonates
most potent blood buffer
bicarbonates
pH level of blood
7.35 - 7.45
human kidney receives __% of the blood
25% or 1/4
blood enters the nephron via _____ ____
afferent arteriole
blood flows through the glomerulus and into the ___ ____
efferent arteriole
the main source of of blood that enters the nephron
renal artery from left ventricle of heart
blodo from the efferent enters the ___ ___ and the ____ (for immediate reabsorption)
peritubular capillaries , vasa recta
average size of the kidney
1.74 m2
total renal blood flow per min
1200 ml/min or 1.2 Liters per minute
total blood volume
5 liters
total renal plasma flow per min
600-700 mL/min (half because composition of blood is 50% plasma)
nephron: long loop, glomerulus closer to cortex medulla, efferent supplies vasa recta
juxtamedullary nephron
nephron: short loop, glomerulus further from cortex medulla, efferent supplies peritubular capillaries
cortical nephron
cortical radiate artery will become smaller to ___
afferent arteriole
where tubular secretion may happen
distal convoluted tubule
after blood filtration, what artery will be used
efferent arteriole
in order of tubular reabsorption flow
- proximal convoluted tubules
- descending loop of henle
- ascending loop of henle
- distal convoluted tubule
- collecting ducts
when blood goes back tot he heart, what blood vessel is utilized
renal vein
after the collecting duct, it goes to the ___ ___ then ___ ___ then ____ ___ which is the triangular area then ___
- minor caluces
- major caluces
- renal pelvis
- ureter
difference between peritubular capillaries vs vasa recta
peritubular - surrounds proximal and distal
vasa recta - surrounds loop of henle
nonselective filter of plasma substances with a molecular weight of less than 70k
glomerulus
4 factors influencing filtration process
cellular structure of the glomerulus
hydrostatic pressure
oncotic pressure
feedback mechanism of RAAS
simply imagine that this is the blood pressure or the force exerted by the body that affects the filtration process
hydrostatic pressure
pressure produced by the solutes like the albumin in the blood
oncotic pressure
space in the bowman’s capsule
bowman’s space
3 layers that the plasma filtrate must pass in the glomerulus
- capillary wall membrane
- basement membrane (basal lamina)
- visceral epithelium of the Bowman’s capsule
___ increase capillary permeability but do not allow passage of large molecules and blood cells in glomerulus
pores
what causes further restriction of large molceules in the glomerulus
basement membrane
podocytes - thin membranes covering filtration slits
foot like processes that enchanes the filtration
podocytes
first part in the glomerulus where urine accumulates
bowman’s space
what do you call it pag nakapass siya sa tatlogn layers ng glomerulus but babalik parin becuase of ____
shield of negativity (presented by albumin)
regulates the blood flow to and within the glomerulus
Renin-Angiotensin-Aldosterone System (RAAS)
responds to changes in the blood pressure and plasma sodium content
RAAS
helps the urine formation because if there is low blood pressure and low plasma sodium, mababa ung daloy ng dugo sa katawan
RAAS
CIte the steps of RAAS
- low blood pressure, plasma sodium
- Renin secretion
- Angiotensin 1; (angiotensinogen)
- Angiotensin 2 (angiotensin converting enzymes)
- Vasoconstriction
- Proximal convoluted tubule for sodium reabsorption
- angiotensin 2 activates aldosterone in renal cortex; then goes to distal convoluted tubule for sodium reabsorption
- ADH produced in hypothalamus in posterior pituitary gland goes to collecting duct for water reabsorption
concentrating ability of the kidney
tubular reabsorption
substances are removed from the glomerular filtrate and returned to the blood
tubular reabsorption
2 types of cellular mechanism involvled in tubular reabsorption
Active transport -passive transport
plasma concentration where the active transport stops
renal threshold
glucose renal threshold
160-180
substances reabsorbed in the PCT
glucose
amino acid
salts
most important substances are reabsorbed here as early
PCT
type of transport of glucose, amino acids, salts in PCT
active transport
actively reabsorbed in ascending loop of henle
chloride
actively reabsorbed in proximal and distal CT
sodium
t/f: all renal tubules are capable of water reabsorption except descending loop of henle
false, ascending loop of henle
passively transported by PCT and ascending
Urea
t/f: Urea is passively reabsorbed even though we dont want it because there is high concentration of it in the urine
true
passively reabsorbed in the ascending
sodium
begins in the Descending and Ascending Loop of Henle
Renal concentration
Water is removed by osmosis in the _____
Descending Loop of Henle
Na and Cl are reabsorbed in the _____
Ascending Loop of Henle
unidirectional flow of the urine, to ensure that the urine would flow towards the collecting ducts and the other way around na pabalik sa glomerulus
countercurrent mechanism
selective reabsorption process
countercurrent mechanism
serves to maintain the osmotic gradient of the medulla
countercurrent mechanism
involves the addition of substances form the blood
tubular secretion
Involves the passage of substances from the blood in the peritubular capillaries to the tubular filtrate
tubular secretion
2 major functions of tubular secretion
- eliminate waste products not filtered by the glomerulus
- regulation of acid base balance through secretion of H ions
determined to be a glomerular filtration test except _____ because it is part of tubular reabsorption test
Free water clearance test
measures the rate in milliliters per minute at which the kidneys are able to remove a dilterbale substance from the blood
GFR
unit used in GFR
ml/min
charactersitics of substance to be tested
- not reabsorbed/secreted by tubules
- stable for 24 hrs
- constant plasma level
- available in body
- availability of test
urea clearance test requires __ sample
2 hour sample
___ is naturally found as the most organic abundant in urine and it can be a factor to differentiate urine from other bodily fluids
urea
earliest clearance test
urea clearance test
t/f: in urea clearance test, the patient must be properly hydration to prevent more than 40% reabsorption of urea
true
problem in urea clearance test
reabsorbed by the tubule
t/f: urea clearance test is now an obsolete test
true
most accurance clearance test in the past
inulin clearance test
synthetic substance from fructose that is not originally part of hte systemic circulation
inulin
disadvantage of inulin clearance test
infused at constant rate
creatinine clearnac etest requires __ sample
24 hour urine sample
endogenous procedure for evaluating glom filtration
creatinine clearance test
body surface area factor
1.73
ref range for male creatining clearance
107 - 139 ml/min
ref range for female crea clearance
87 - 107 ml/min
used for routinely screening patients as part of a metabolic profile and to monitor patients already diagnosed with renal disease or at risk for renal disease
Est. GFR
MDRD
modification of diet in renal disease
formula for GFR
175 x serum crea^-1.154 x Age^-0.203 x 0.742 for females or x 1.212 for black race
produced by all nucleated cell at constant reate
cystatin C
substance that is endofenous kasi naturally found by all nucleated cells
Cystatin C
Filtered readily by the glomerulus and reabsorbed and broken down by the renal tubular cells
Cystatin C
advantage of Cystatin C
Independent of muscle mass
clearnace test recommended for pedia, elders, diabetic, crit ill
cystatin C
Missociates from human leukocyte antigen at constant rate
B2M
Removed rapidly from the plasma by glomerular filtration
B2M
Most sensitive indicator of a decrease in GFR
Beta 2-Microglobulin
salts and water are reabsorbed in the tubules
tubular reabsorption test
Used to determine the ability of the tubules to reabsorb essential salt and water that have been non-selectively filtered by the glomerulus
concentration test
Urine concentration is largely determined by the body’s state of hydration
tubular reabsorption test
2 obsolete test in tubular reabs
mosenthal
fishberg
high spec gravity of urine
1.018
Measures only the number of particles in a solution
osmolality
factor for GFR female
0.742
factor of black in GFR
1.212
comparison of day time and night time urine test
mosenthal test
in mosenthal test, spec gravity at night can be as high as _
1.018
test that deprives the person of water for 24 hours
fishberg test
in fishberg test, at 16th hour, the spec gravity should be ___
1.025
2 colligative properties tested in tubular reabsorption test
freezing point osmometers
vapor pressure osmometers
uses reagent strips
spec grav determination
same reagent formula for crea clearnace but basis is osmolality and the use of osmometers
free water clearance
tranditional but not used anymore test for tuular secretion and renal blood flow
PSP - phenolsulfonpthalein excretion test
most commonly associated with tubular secreitona dnrenal blodo flow that replaced PSP
PAH - P-aminohippuric acid
exogenous substances used and it is a test for kidney function
indigo carmine test
uses oral acid load of ammonium chlroide
titratable acidity and urinary ammonia
reference range of titratable acidity and urinary ammonia
70 mEq/day of acid in the form of titratable hydrogen ions or ammonium ions
