Anatomy, Embryology, and Imaging of the Kidney Flashcards Preview

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Flashcards in Anatomy, Embryology, and Imaging of the Kidney Deck (36):

What are the top, bottom, left, and right sides of the kidney called?

The superior and inferior poles.
The lateral and medial borders.


Average length of a human kidney?
How does the left vary from the right?

Average length is about 11cm, but depends on the size of the person.
The right kidney is a little "squashed" by the liver.


About how much kidney function must a person lose before symptoms appear?
(How does this affect determining acute vs. chronic kidney injury?)

About 90%.
(Because both acute and chronic injury can have a rapid onset of symptoms, it can be difficult to determine acute vs. chronic from timeline alone.)


How does chronic kidney injury often change the size of the kidneys?

Chronically injured kidneys are often smaller with scarring/fibrosis.


How can the cortex appear altered on ultrasound of a chronically injured kidney?

The cortex of a chronically injured kidney will often have more areas of echodensity.


What vertebral levels do the kidneys typically span?

T12 - L3


If you were biopsy-ing a kidney, would you go from the front?

Nope, there's lots of stuff to hit. Better to go from the back, hitting the part of the kidney not protected by the ribs. (though there are still a few splanchnic nerves one could hit...)


What are the renal "papilla"?

Each pyramid, composed of medulla, ends in a papilla draining into a minor calyx.


Where are the renal sinuses?

Between the minor calyces.
(they're often filled with fat and have blood vessels running through them)


What are the renal columns?

Extensions of the cortex between the pyramids. Not much action there.


What are the medullary rays?

A number of structures, but notably, collecting ducts that drain down into larger ducts. (more on these next lecture)


What's downstream of the minor calyces?

Minor calyces -> major calyces -> renal pelvis -> ureter.


Should you be able to see the renal calices on normal x-ray? What if you do?

No. If you do, it suggests a problem like a big "staghorn" kidney stone.


What does a ureter / other renal outflow obstruction look like on ultrasound? What is this process called?

Dilated renal pelvis/calyces (which are echo-lucent).
This is called hydronephrosis.


How many major branches does each renal artery give off? What's the term for the arteries at this level?

Each renal artery gives off 5 "segmental" arteries - 4 anterior and 1 posterior.


About how much kidney function will be lost if one segmental artery is completely occluded?



What are the names of the "levels" of arteries after segmental arteries?

Segmental -> interlobar arteries -> arcuate arteries -> interlobular arterioles.


How would you treat a severe kidney bleed (eg. from trauma)?

Coil embolization of the segmental artery upstream of the bleed.


3 layers of the ureter wall?

Mucuous coat


How does the ureter opening into the bladder help prevent reflux?

The superior part of the ureter extends into the lumen of the bladder, such that when the bladder is distended it compresses and closes the opening to the ureter.


Anatomy review: What is the name of the structure in the bladder where the ureters enter?

The trigone.


3 causes of obstruction of the ureter "from within"?

Kidney stones.
Blood clots.


Can lots of things cause an external obstruction of a ureter?

He highlighted iliac artery aneurysm as an example.


3 portions of the male urethra?



What germ layer, and what part of it, gives rise to the kidneys?

Intermediate mesoderm.


What are the excretory organs that exist in humans from week 3-5?

Pronephros - don't worry about them.


What's the second excretory organ to develop in the embryo?

The mesonephros.
(these become testes/etc. in males, regress in females)


What embryonic structure gives rise to final, adult nephrons?

The metanephrons.


When does metanephron development cease?

Week 36 -thus some premature babies will have underdeveloped kidneys.


How do the metanephric blastema and the mesonephric duct talk to eachother to form a kidney?

Metanephric blastema induces ureteric bud.
Ureteric bud promotes blastema differentiation into glomeruli and tubules (mesenchymal -> epithelial transformation).
The ureteric tips and cap mesenchyme are special...


A lot of branching and budding happens when forming the calyces and inducing the million future nephrons.



What might happen if a ureteric bud branches before penetrating the metanephric blastema?

It can give rise to a second ureter for that kidney, or a whole new third kidney.


What's the syndrome that results from in utero kidney dysfunction?
What's the primary deficit that drives the defects?

Potter's syndrome: kidney dysfunction -> oligohydramnios, i.e. not enough amniotic fluid.
(forehead, ears, nose, fingers, lungs are adversely affected)
(injecting saline to take the place of missing amniotic fluid has yielded promising results, but the kids will still need kidney transplants)


Does the arterial supply change as the kidneys ascend to their final position?

Yes. They stimulate new vessel budding from the aorta as they travel up, eventually getting to the renal aa.


What's a horseshoe kidney? Why doesn't it ascend all the way?

Left and right kidney are fused at the inferior pole.
It can't ascend all the way because it gets stuck on the inferior mesenteric artery.


How can supernumerary renal arteries cause a problem?

They can cause external obstruction of the ureter.
And if a surgeon doesn't realize that it's there, it can be a problem.