Renal Anatomy and Histology Flashcards
Ureter relation to testicular/ovarian arteries and common iliac
Ureter passes posterior to the testicular/ovarian arteries and anterior to the common iliac at its bifurcation into internal/external
Ureter in relation to uterus
Passes underneath the uterus
Right kidney vs left kidney location
Both located about T12-L3
Right kidney is lower because liver pushes it down
4 procedures the ureter could possibly be damaged
Pelvic dissection
Ligation of uterine vessels
Ligation of gonadal vessels
Dissection of bladder/vagina
Renal nutcracker syndrome
Superior mesenteric artery compresses the left renal vein while it passes underneath
Hematuria, proteinuria, nausea/vomiting, left sided varicocele
Blood supply from aorta through kidney and back to inferior vena cava
Aorta–>Renal artery–> Segmental artery–> interlobar artery–> arcuate artery–> cortical radiate artery–> afferent arteriole–> glomerulus–> efferent arteriole–> peritubular capillaries and vasa recta–>cortical radiate v–> arcuate v–> interlobar v–> renal v–> IVC
Sympathetic innervation to kidneys
Lesser and least splanchnic nerves
-Synapse in aorticorenal ganglia
Lumbar splanchnic nerves as well
Parasympathetic innervation to kidney
Vagus nerve
Urine forming and carrying units made of
Nephron - consists of renal corpuscle and renal tubules
-Juxtamedullary (in medulla) and cortical (in cortex) nephrons
Glomerulus endothelium
Fenestrated
Descending vs ascending vasa recta
Ascending is fenestrated
Descending is continuous endothelium
Mesangial cells
Structural support for glomerular loops
Phagocytic cells
Prevents glomerular distension due to high glomerular BP
Secrete growth factors and cytokines in response to injury
What indicates a damaged glomerular basement membrane
Albuminia- albumin in urine
What are the components of the filtration membrane
Glomerular fenestrations
Glomerular basement membrane
Podocyte foot processes
Parietal layer of bowmans is what type of epithelium
Simple squamous
Proximal convoluted tubule
Only in renal cortex
Most active tubule in resorption and secretion
Simple cuboidal–>simple columnar
Abundant microvilli and mitochondria
Loop of henle thin descending segment
Simple squamous w/o brush border
Main function is water reabsorption
Loop of henle ascending segment
Thick:
Simple cuboidal w/numerous microvilli
Impermeable to water
25% sodium reabsorption
Na/K/2Cl (NKCC2) cotransporter establishes the concentration gradient in the interstitium
Increase in K concentration in the cells causes back diffusion of K into the tubular lumen, allowing a lumen-positive electrical potential to drive reabsorption of cations (Mg, Ca) via the paracellular pathway
Thin:
Relatively impermeable to water, other ions/solutes
Distal convoluted tubule
Only found in renal cortex
Simple cuboidal epi
Angiotensin II influences Na reabsorption
Impermeable to water
10% NaCl reabsorbed
Na/Cl cotransporters transport NaCl out of lumen
Ca reabsorbed by calcium channels regulated by PTH
Tubular fluid is diluted here
Macula densa
Tight nuclei at distal end of thick ascending loop of henly
Monitors Na levels
Signal release of renin if Na is low
Collecting tubules/ducts
Final urine osmolarity determined here by water reabsorption
Target of both ADH and aldosterone increasing water reabsorption and Na reabsorption, respectively
Lined with simple cuboidal epithelium, simple columnar at distal end
Several ducts join together to form larger papillary ducts that then drain into renal minor calyx
Principal cells
Target of aldosterone
Intercalated cells
Involved in H+ and bicarbonate transfer
Cortex contains:
Renal corpuscles, convoluted and straight tubules of nephron, portions of collecting ducts
Medulla contains
Renal columns and pyramids, loops of henle, collecting tubules
Transitional epithelium- keeping barrier to urine
Contains umbrella cells in superficial layer which have urothelial plaques made up of largely uroplakin proteins
When bladder is distended, these plaques move to surface and form impermeable barrier to the hypertonic urine
When it is empty, these plaques are endocytosed and stored
Bladder location
Anterior to uterus and rectum, sitting within pelvis
Can expand into abdomen when very full
Female urethra length, UTI
It is shorter than male, therefore more susceptible to UTI
E. coli usually
Male Prostatic vs membranous vs spongy urethra epithelium
Prostatic-Transitional
Membranous- pseudostratified/stratified columnar
Spongy urethra- pseudostratified/stratified columnar proximal, stratified squamous distally
Female proximal vs intermediate and distal urethra epithelium
Proximal- transitional
Intermediat/distal- nonkeratinized stratified squamous
Polycystic kidney disease
Cysts that form crush tissue and impede drainage
Eventually leads to kidney failure and BP dysregulation
Hypertension, renal hemorrhage, UTI
Dialysis or kidney transplant only options
Schistosoma hematobium
Parasitic blood flukes
Genitourinary tract disease
Chronic infection can cause fibrosis and calcification of bladder
Risk for bladder cancer
Proximal tubule reabsorption
Active reabsorption 85% sodium bicarbonate 65% NaCl 65% K+ 100% glucose and amino acids Passive reabsorption Water Carbonic anhydrase highly active here Na/K ATPase maintains low intracellular Na levels This is where drugs such as diuretics, NSAIDs, Abx are secreted into the lumen from the blood
Collecting tubule reabsorption
Epithelial Na channel ENaC
-responsible for 2-5% Na reabsorption which creates electrical gradient that facilitates K+ secretion down the concentration gradient
Most important area of K+ secretion by kidney
This is where diuretic-induced changes in K+ balance occur- more Na delivered to collecting tubule means more K+ secretion
Proton pumps increase urine acidity here *
Aldosterone effect on collecting tubule
Increases the expression of ENaC and basolateral Na/K ATPase–>increases Na reabsorption and K+ secretion–> water retention and increase in blood volume and BP
Where does ADH have its effect
On the collecting tubule
Controls permeability of tubule to water by regulating expression of aquaporin-2 channels
Alcohol inhibits ADH release
