urinary system Flashcards
what are the functions of the urinary system (8)
excretes waste in urine
regulate blood volume
regulate blood composition
regulates BP
regulates blood pH
regulate blood glucose levels
produces calcitriol
produces erythropoietin
what are 4 metabolic waste products
urea, creatinine, uric acid, bilirubin
what is urea
breakdown of amino acids
what is creatinine
breakdown of creatine phosphate in muscles
what is uric acid
catabolism of nucleic acids
what is bilirubin
catabolism of hemoglobin
what is catabolism
the breakdown of larger moleculse into smaller, to produce energy
through what chemical ions do the kidneys regulate blood composition
sodium, potassium, calcium, chloride, and phosphate ions
what are the 2 types of blood acidosis
metabolic acidosis - kidneys not functioning enough
respiratory acidosis - not enough CO2 being blown out
which electrolyte is in the intracellular fluid
potassium
which electrolyte is in the extracellular fluid
sodium
what (3) electrolytes are responsible for bone health
calcium
magnesium
phosphate
which kidney is more inferior
why
the right
because of the liver
at which angle are the kidneys
obliqued 30 degrees anteriorly
at what vertebral level are the kidneys
T12 - L3
which end (sup/inf) of the kidney is more posterior?
the superior end is more posterior
which ribs partially protect the kidneys?
11 and 12
where do the ureters enter the bladder
through the floor, close to the midline
where is the renal hilum directed
30 degrees from the coronal plane
towards the aorta
what does an RPO 30 degrees oblique best demonstrate
the left kidney
how does RPO 30 deg oblique demonstrate the right kidney?
in profile
what is 1
the right kidney
what is 2
the left kidney
what is 3
ascending colon
what is 4
descending colon
what is 5
the abdominal aorta
what is 6
the inferior vena cava
what structures are anterior to the right kidney (4)
right lobe of liver
descending duodenum
hepatic flexure
ascending colon
what structures are anterior to the left kidney (4)
tail of pancreas
stomach
splenic flexure
descending colon
where (peri wise) are the kidneys
retroperitoneal
what are the 2 capsules around the kidney
renal capsule
adipose capsule
what is the innermost capsule of the kidneys
renal capsule
what does the adipose capsule do
protect
hold kidneys in place
what is nephron ptosis
the dropping of the kidneys from supine to erect
what body type would have the greatest amount of nephro-ptosis
asthenic
(has the least fat)
what is the outermost capsule of the kidneys
the renal fascia
what does the renal fascia do
connect kidney to
abdominal wall, lumbar vertebrae, and diaphragm
to what extent do the kidneys experience respiratory excursion from full inspiration to full expiration **
up one inch
does the renal cortex include the renal columns
yes!!
what do the renal columns do
anchor the renal cortex
which is the outer layer of the kidneys
the renal cortex
how many renal pyramids is typical
8-18 renal pyramids
what is the renal medulla
the inner layer of the kidneys
8-18 pyramids, renal papilla
how many minor calyces does a person have (per kidney)
8-18
the same number as that of pyramids
at what point is filtrate considered urine? why?
at the minor calyces
the concentration can no longer change
how many major calyces is typical (per kidney)
2-3
what is the drainage order of the kidneys
pyramids (in medulla)
minor calyces
major calyces
renal pelvis
ureter
what type of arteries run through the renal columns
interlobar arteries
give numbers for the structures following the flow of urine
minor calyces (8-18)
major calyces (2-3)
renal pelvis (1)
ureter (1)
why is the right kidney so dark
not picking up contrast (dark)
therefore no filtration happening
therefore pathology present
what is the functional unit of the kidney
the nephron
how many nephrons are in each kidney
1 million
where are nephrons located
in the renal cortex and renal medulla (pyramid) of the kidneys
what are the 2 parts of the nephrons
renal corpuscle
renal tubule
what is the renal corpuscle
responsible for actually filtering the blood
what are the 2 parts of the renal corpuscle
glomerulus
bowmans capsule
what is the glomerulus
a network of capillaries in the renal corpuscle
what is the Bowman’s/glomerular capsule
a double walled cup in the renal corpuscle
where is the filtration taking place
in the renal corpuscle
what are the 3 parts of the renal tubule
proximal convoluted tubule
loop of Henle (nephron loop)
distal convoluted tubule
how much of the resting cardiac output is being received by the kidneys
20-25%
which renal artery is longer
the right
because the abdominal aorta is to the L of the midsagittal plane
name the blood flow from renal arteries to nephron (6)
renal arteries
segmental arteries
interlobar arteries
arcuate arteries
cortical radiate arteries
afferent arterioles
how many segmental arteries does each kidney have
5
where do the interlobar arteries pass
through the renal columns
where are the arcuate arteries
the arch between the renal medulla and cortex
where do the cortical arteries run
radiate outwards into the renal cortex
what artery supplies the capillary network
glomerulus
what artery carries blood AWAY from the glomerulus
the efferent erterioles
where are the peritubular arteries
surrounding the tubular parts of the nephron
what is the different between the afferent and efferent arteries
the afferent arteries are BIGGER
what are the 2 types of nephrons
cortical and juxtamedullary
what percentage of nephrons are cortical nephrons
80-85%
what percentage of nephrons are juxtamedullary
15-20%
what is the difference between cortical and juxtamedullary nephrons
cortical - renal corpuscles in outer part of cortex
short loop of henle
juxtamedullary - renal corpuscles lie deep in the cortex
long loop of henle
why is the glomerulus “leaky”
large fenestrations (pores)
allows solutes to leak out, but NOT BLOOD CELLS
what are the layers of the Bowman’s casule
visceral (inner) layer
parietal layer
where is filtrate collected
in the capsular space of the Bowman’s capsule
what is between the PCT and DCT
loop of henle
what are the 2 parts of the loop of henle
descending and ascending loops
what 2 cell types does DCT have
principal cells
intercalated cells
what are principal cells
receptors for ADH and aldosterone
what are intercalated cells for
homeostasis of blood pH
what are the 3 steps to renal physiology
glomerular filtration
tubular reapsorption
tubular secretion
what is glomerular filtration
in the mlomerulus, blood plasma and dissolved substances get filtered INTO the glomerular capsule
what is tubular reabsoprtion
along the renal tubule, substances get reabsorbed back into the blood
what is tubular secretion
any substances left (waste) in the tubule make their way into the urine
why is the volume of fluid filtered in glomerular filtration so great
large surface area
thin porous filtration membrane (0.1mm thick)
high glomerular blood pressure
why is the glomerular blood pressure so high
afferent arteriole is larger than the efferent arteriole
what is GBHP
glomerular blood hydrostatic pressure
what is CHP
capsular hydrostatic pressure
what is BCOP
blood colloid osmotic pressure
what is hydrostatic pressure
pushes fluid OUT
what is osmotic pressure
pulls fluid IN
what does GBHP do
promotes filtration (pushes fluid from blood to Bowman’s capsule
what does CHP do
back pressure from fluid already in bowmans capsule
what does BCOP do
pulls fluid back into the blood
how strong is GBHP
55 mmhg
how strong is CHP
15 mmhg
how strong is BCOP
30 mmhg
NFP = ? (formula)
NFP = GBHP - CHP - BCOP
what is the average NFP
10 mmhg
what happens if GBHP passes below 45
no filtration occurs (NFP is 0)
what happens to the NFP when the afferent arteriole dilates
greater NFP
what happens to the NFP when the efferent arteriole dilates
lesser NFP
what is GFR word and desc
glomerular filtration rate
= the amount of filtrate formed by both kidneys each minute
what is used to measure how well the kidneys work
GFR
what is the average GFR for males and females
males 125mL/min
females 105mL/min
can you measure GFR in real life?
no EGFR is used instead
what things are needed to know an EGFR (4)
creatinine level (blood test)
age
gender
race (black or other)
GFR (increases/decreases) with age
decreases
what is the highest eGFR level that is great
90 or more
what eGFR range is needed to ask before injection
30-60
what level indicates renal failure (and you must be SO careful when injecting)
<30
what 2 things regulate GFR
- adjusting blood flow in/out of glomerulus
- altering glomerular capillary surface area
what body process requires a constant GFR
body fluid homeostasis
what happens when GFR fluctuates too high
may lose needed substances
what happens when GFR fluctuates too low
may not have enough filtration (waste products do not get excreted)
what 3 processes regulate GFR
renal autoregulation
neural regulation
hormonal regulation
what are the 2 mechanisms of renal autoregulation
myogenic mechanism
tubuloglomerular feedback
what is the myogenic mechanism
(normalizes GFR in seconds)
when BP rises, stretch receptors trigger constriction in the afferent arterioles
what does tubuloglomerular feedback do
detect increas of Na/Cl/water
inhibits nitric oxide in juxtaglomerular apparatus, constricting the afferent arterioles
where is the receptor for tubuloglomerular feedback
in the DCT
how/when does neural regulation work
emergency hemmorrhages or dehydration
constricts afferent and efferent to conserve blood for the heart and brain
what happens to most of the filtrate in the tubules
it is reabsorbed back into the bloodstream
what is the different between active and passive transport
active requires energy and passive does not
what percentage of water is reabsorbed
99%
how much urine is produced on average
1.8L (males)
solute reabsorption drives what
water reabsorption
water reabsorption happens via what
osmosis (passive)
what are the 2 categories of water reabsorption
+ their percentages
obligatory WRA 90%
facultative WRA 10%
where does obligatory WRA happen
PCT and descending loop of henle
does obligatory WRA require energy
no, passive
what does facultative mean
capable of adapting to a need
facultative WRA is regulated by what
ADH - antidiuretic hormone
where does facultative WRA happen
DCT and collecting ducts
what is tubular secretion
how we’re getting rid of waste projects (controls pH level)
where does tubular secretion happen
site other than filtration membrane
PCT, DCT, collecting ducts
what ions are secreted in tubular secretion
hydrogen and ammonia (urea)
how much water is reabsorbed
178-179 litres
how much water is secreted
1-2 litres
how much glucose shold be present in the urine
0 g
what does glucose in urine mean
indication for diabetes
where does the majority of water absorption happen
in the PCT
describe the descending loop (of Henle) permeability
impermeable to solutes, permable to water
describe the ascending loops (of Henle) permeability
impermeable to water
permeable to sodium and chloride ions
what is countercurrent multiplication
process where loop of Henle pumps NaCl OUT of ascending, allowing for more reabsorption of water
produces concentrated urine
by the end of the DCT, ___ % of water and solutes have been reabsorbed
95
what 2 things happen when blood pressure drops
renin-angiotensin-aldosterone system
ADH release
what is angiotensin II
a potent vasoconstrictor
explain the renin-angiotensin-aldosterone system
renin released from kidneys activates angiotensin I
ACE converts angio I to angio II
angio II contsricts arterioles (inc BP) and triggers adrenal release of aldosterone
aldosterone promotes Na reabsorption > water retention > increase BP
explain the role of the release of ADH when BP drops
promotes facultative water reabsorption in the kidney, back into the blood to increase BP
what happens when BP rises
atrial natriuretic peptide
how does ANP regulate high BP
released from heart when stretched (from too much blood volume)
dilates afferent arteriole
increases GFR, decreases BP
what is ANP
atrial natriuretic peptide
what is shown here
“the nephrogram pahse”
only in nephrons, IMMEDIATE
what is shown here
contrast in minor and major calyces
how many major calyces are shown here (on each side)
2 in each kidney
where are the ureters
retroperitoneal
anterior to psoas muscle
what portion of the ureter is the most anterior
the middle
how long are the ureters
10-12” long
what moves the urine to the urinary bladder
peristalsis, plus gravity
what is the UPJ
uteropelvic junction
“up” junction
what is the UVJ
uterovesicle junction
does the UVJ have an anatomic valve?
no
what is 2
ureter
what is 7
IVC
what 3 places do kidney stones get caught
UP junction
UV junction
pelvic brim where the iliac vessels cross anteriorly
RPO 30 deg oblique best demonstrates what
right UP junction
LEFT kidney
RPO 45 oblique
left UV junction
how to best demonstrate right UP junction
RPO 30 deg oblique
how to best demonstrate left kidney
RPO 30 oblique
how to best demonstrate left UV junction
RPO 45deg oblique
what is shown here
phleboliths - calcified vessel or vein
what does phlebo mean
veins
what are common calcified gastric veins, commonly shown in pelvic images
phleboliths
how much urine can the bladder hold
700-800 mls
what shape is the bladder
round
pear shaped when super full
what is the trigone of the bladder
the smooth part with no rugae
what does the trigone of the bladder contain
2 uretal openings
1 internal urethral orifice
does the bladder have rugae
all but the trigone does
what is this image used to view
if there’s any urinary reflux
(ureter has no valve)
why can urinary reflux be bad
because bladder infections could travel up to the kidneys
in females, the bladder is inferior to the ___
uterus
how long is the female urethra
4cm
how long is the male urethra
20 cm
what are the 3 distinct parts of the male urethra
prostatic
membranous
spongy
what is 10
bladder
what is 11
urethra
what is 15
pubic symphysis
what is 6
spongy urethra
what is 11
membranous urethra
what is 12
prostatic urethra
what is 20
urinary bladder
where does a transplanted kidney go
down in the pelvis, on the swapped side (?)
what is being shown here
calcified bones
osteolastic lesions
what levels do the kidneys go from
T12 to L3
