C7: Urinary Tract Flashcards
which tissue do the kidneys arise from?
what are the 3 stages of development?
mesoderm
- pronephros
- mesonephros
- metanephros
decribe the pronephros
when do they form
- form early in the 4th wk of embryonic development
- non-functioning/rudimentary
decribe the mesonephros
when do they form?
what structure do they eventually become
- form late in the 4th wk of embryonic development
- function as interim kidneys
-eventually form the mesonephric duct (wolffian duct)
what does the mesonephric duct form in M and W?
when are ureters formed?
M: epididymis, vas deferens, ED
W: mullerian duct which forms the vagina and uterus
Form ureters for M and W @ 4 wks gestation
decribe the metanephros
when do they form and when do they start functioning
- permanent kidneys
- form @ end of 5th wk… function @ ~8wks
when do they kidneys migrate from pelvis to abdo? wks
why does this occur?
12-15 wks
-due to rapid caudal growth (not really migration)
where does the bladder develop from?
which structure does it connect to in utero?
urogenital sinus
-connects to allantois
what does the allantois become?
where does it develop?
develops in yolk sac
-becomes urachus…. urachus becomes the median umbilical ligament
(urachus is the opening or pathway the bladder moves through to go from lower abdo to pelvis…. should seal off)
when does the bladder become a true pelvis organ?
after puberty
describe the location of the kidneys
- retroperitoneal in the perirenal space
- oblique to the paravertebral gutters
- parallel to psoas
- posterior and lateral to IVC and AO
describe the location of the poles of the kidney
- upper poles are posterior and medial
- medial margins are more anterior than lateral margins
where do the ureters enter the bladder?
relationship to iliacs?
- posterolateral aspect
- anteior to iliacs
where are the ureters the narrowest?
length?
UPJ… ~8mm
30cm length
(UVJ is ~2mm)
are ureters retroperitoneal?
yes
describe the location of the bladder
extraperitoneal
- empty: true pelvis
- full: into false pelvis
for M:
-superior to prostate
norm width and AP of adult kidney?
how different can the 2 kidneys be in length?
w: 4-5cm
AP: 3cm
1.5cm different (L usually longer)
list the protective layers of the kidney and describe them inner to outer
- fibrous capsule
- perirenal fat (adipose)
- continous with renal sinus - renal fascia (gerotas fascia)
- anchors kidneys and adrenals to post. abdo wall
- seperates perirenal space from pararenal space - pararenal fat
- outside gerotas fascia
what is ptosis
when kidney falls due to tear in fascia (renal fascia)
what is the kid parenchyma? what is it composed of?
functional tissue
-made of cortex and medulla
what is the renal cortex
describe its location, what tissue does it contain and what function does it carry out?
- outer part below the real capsule
- columns of Bertin project b/w the renal pyramids towards the sinus and each have their own interloper artery and vein
- contains nephrons (functional units of kidney)
- site of urine production
what is the renal medulla
- inner part
- contains pyramids (8-18)
describe how the renal pyramids are positioned in the kidney
when are pyramids considered enlarged?
base directed towards the cortex and apex directed towards renal sinus
-when they’re thicker than cortex
what is the renal sinus?
which structures does it contain?
- fatty central portion which is continuous with perirenal fat
- contains calyces, renal pelvis, vessels and nerves
what are the functions of the minor and major calyces?
how many of each?
minor (8-18): receive urine from pyramids
major (2-3): join to form renal pelvis which leaves the sinus as the uereter
another term for the major calyces
infundibula
list the structures that enter and leave the renal hilum from anterior to posterior
- Renal vein
- renal artery
- ureter
- third branch of renal artery
what are the uerters? how do they transport urine
what are there 3 point of narrowing?
-muscular mucosal lined tubes that carry urine through peristalsis and gravity
- UPJ -ureteropelvic junction, where ureters insert into kid
- pelvic brim
- UVJ - ureterovesicular junction- entrance to bladder (narrowest point, where stones get lodged)
what are the folds within the bladder? how do they appear in empty vs full state
rugae
- empty: wrinkled
- full: smooth
capacity of bladder?
what post void volume is non significant
300-500 ml
<100ml
what is the trigone?
wheres it located?
- triangular area of b/w openings of ureters and urethra… doesnt change shape
- located on base/posteior surface of bladder
what is the bladder neck?
does it change shape?
urethral orifice
…doesnt change shape
wheres the apex of the bladder located?
does it change shape?
which ligament attaches here?
the anterior and superior part of the bladder… yes changes shape
-median umbilical ligament
what are the 4 layers of the bladder wall?
- Mucosa
+ inner layer, contains the rugae - Submucosa
+ connective tissue - muscle
+ made of detrusor muscle
+has 3 layers
+ forms sphincter muscles - serosa
+ peritoneal covering
how thick should the bladder wall measure
full: 3mm AP
empty: 6mm AP
what is the urethra?
how is it different in M and W
membranous canal leaving the bladder at the trigone
W: canal pierces the urogenital diaphragm
M: longer and had 3 areas (prostatic, membranous, penile)
where do the renal arteries branch off AO?
how does the RRA travel?
- from the lateral aspect bell the level of the SMA
- posterior to IVC
describe the divisions of the renal arteries
- Renal arteries divide into several branches before entering the kidney… then…
- The renal arteries divide into interlober arteries which travel b/w pyramids
- Interlobar divide into arcuate arteries which are at the base of the pyramids
- Arcuate A divid into interlobular arteries which travel into the renal cortex
- Interlobular divide into afferent arterioles that carry blood to the glomerulus of the nephron
what is the CMJ
what measurement is it a marker for?
corticomedullary junction- border b/w the cortex and medulla where the arcuate artery is located… will appear echogenic and pulsatile
-for measuring the cortical thickness
how does the echogenicity of the kid cortex compare to liver?
how should pyramids be spaced in the kidney?
isoechoic to or slightly LESS echogenic to the liver (compare at same depth)
-equidistant
when are the renal pelvis and infundibulum not seen on US?
if they are collapsed due to lack of hydration
which structures can commonly be mistaken for the renal arteries?
crux of diaphragm
how will kid cortex of neonates/infants appear on US
- isoechoic or more echogenic than liver
- thin compared to pyramids
- lobular contour that goes away by 6yrs
how will the size of kidney pyramids of neonates/infants appear on US
-larger than adults
how will kid sinus of neonates/infants appear on US
indistinctive due to little fat
how do kidneys sit in the abdo of children compared to adults?
when should children show adult kid patterns?
lower in the abdomen
-should show by 6 months
do we often visualize ureters?
no, not unless dilated
What’s the relationship of the R kid to the hepatic flexure and the diaphragm
Hepatic flexure is anterior to kidneys and diaphragm is posteriorto the kidney
If the ureters are dilated, or if there’s hydronephrosis, what should you look for?
Jets in the bladder to see if its blocked
If there’s a mass in the bladder, what should you check the kidneys for?
Hydronephrosis
What is the modality of choice for evaluating the bladder?
Cystoscopy
What waste does the kidney remove from the blood?
Metabolic waste- CO2, urea, Uris acid, creatine
List the main functions of the kid
Removes metabolic waste
Balances H20 and electrolytes
Maintains blood pressure
Where is the location of the nephron
Partially in the cortex and medulla
What’s the main function of the nephron
Filters blood and produces urine
- helps control blood concentration and volume
- regulates pH
What are the 2 types of nephrons
Juxtamedullary (deep)
Cortical (superficial)
What are the 2 main parts of the nephron
- Renal Corpuscle
- contains a network of capillaries (glomerulus)… and a membrane with filtration slits (Bowman’s capsule) - Renal tubule
- contains the proximal convoluted tubule, distal convoluted tubule, loop of henle and collecting duct
How does the nephron filter the blood
Through osmosis and active transport
Describe the route that blood takes to get to the nephron
Renal artery>interlobar artery> accurate artery> interlobular artery> afferent artery> Glomerulus
What are the 3 processes involved in urine formation
- Glomerular filtration
- tubular reabsorption
- Tubular secretion
Describe how glomerular filtration works
Where does it occur?
- Afferent arterioles carry blood to the glomerulus, then an increased in BP forces H20 and dissolved substances through the membrane
- this H20 and dissolved substances pass into the Bowman’s capsule its then called filtrate
- then the filtrate passes through an opening in the Bowman’s into the renal tubule
Do RBCs pass through the membrane and into the Bowman’s capsule?
No
How do the RBCs leave the glomerulus?
Through the efferent arterioles
What is filtrate composed of?
Blood plasma without protein
Describe the process of tubular reabsorption
Where does it occur?
- nutrients in the filtrate are reabsorbed back into blood
- reabsorption occurs via the peritubular capillaries at the PCT, ascending and descending loop of henle
Describe the process of tubular secretion
Where does the path of the fluid travel?
- waste is secreted into the DCT
- controls blood pH
Urine> collection duct> pyramid> renal pyramid
Where is the juxtaglomerula apparatus located?
Which how cells are located in the JA?
-At the point where the DCT, afferent and efferent arterioles come into contact
-granular cells (afferent arterioles)
And
-macular densa cells (DCT)
Where are granular cells located? what do they release
Where are macular cells located? What do they inhibit
-Afferent arterioles
+release renin
-DCT
+ inhibit renin
What’s the main function of the JA?
Regulate BP
What’s the function of ADH? Where and when is it released
- helps with water retention
- released when the blood volume is low
- secreted by the posterior pituitary
What’s the function of Aldosterone? Where and when is it released
- Acts on PCT to control the rate of sodium reabsorption (increases sodium levels)
- released by adrenal cortex when there’s a decrease in blood volume
Is aldosterone influenced by the renin-angiotensin system?
Yes
What’s the function of renin? Where and when is it released
- stimulates the production of angiotensin
- released by the JA in the kidneys when BP is lowered
Angiotensin stimulates the release of what hormone>?
Aldosterone
How much kidney function do you need to lose to see a change in blood test values?
60%
What is a serum creatinine blood test?
When will values be elevated?
How is it related to glomerular filtration levels?
Where is it secreted?
- increased values with renal failure, nephritis and obstruction
- directly related
- kidneys
+MORE sensitive than bun test
What is a bun blood test
Is it as sensitive as serum creatinine
What do increased and decreased levels indicate?
- blood urea nitrogen is the end product of protein metabolism that’s formed in the liver
- value will reflect protein intake and renal excretory capacity
- not as sensitive as serum creatinine
- increased indicate renal dysfunction and dehydration and increased protein metabolism
- decreased: hepatic damage, malnutrition, over hydration
What is a serum electrolyte blood test?
What do increased and decreased levels indicate?
Checked for electrolyte levels in blood
Increased: acute renal failure, glomerulonephritis
Decreased: chronic and acute renal failure (depending on cause)
What amount of RBCs in urine are abnormal?
When would levels be elevated?
Any amount (called hematuria)
-detected in inflammation, tumours, pyelonephritis, calculi
What does WBCs in the urine indicate
Infection, inflammation and necrosis
What is pyuria?
What does it indicate
Pus in the urine
Indicates infection
What’s proteinuria, what amount is abnormal?
When would it be seen?
Protein in urine
Even trace amounts are abnormal
Seen in nephritis, polycystic disease, stones, carcinomas
What does pH of the urine refer to?
What does it mean if urine is acidic or alkaline?
Strength of urine
Acidic: increased hydrogen ions
Alkaline: decreased ions
What is specific gravity urine test?
When would you have low levels/
-measures kidneys ability to contracted urine
Low: renal failure and pyelonephritis
High: increased levels in decreased urine output (dehydration)
What’s the upper limit of norm for a hypertrophied column of bertin?
> 3cm
Is the blood still oxygenated when it passes through the efferent arterioles?
Yes
When does the arterial blood in the kidney become deoxygenated?
As it passes through the peritubular capillaries
