urinary Flashcards
kidney
produces urine
filters blood of toxins, waste products that accumulate through circulation
ureter function
transports urine
smooth muscle tube
urinary bladder function
stores urine
urethra function
conducts urine to the external environment
functions of urinary system
regulate blood volume and ionic composition
regulate blood pressure (by renin + reg of amount of water lost)
regulates blood pH - excretion of H+
excretes nitrogenous waste, toxins, + drugs
location of the kidney
retroperitoneal
L = T12-L2; R = L1-L3
surrounded by perirenal fat, renal fascia, and pararenal fat
adrenal glands
located on superomedial surface of each kidney
also covered by renal fascia
perirenal fat
layer directly around kidney
renal fascia
layer around perirenal fat
descends into pelvic cavity with opening between two sides
very thin
acts as barrier to any fluid from kidneys
pararenal fat
layer around renal fascia
cortex
outer layer of kidney
majority of nephron
medulla
inner layer of kidney
includes pyramid and renal columns
loop of Henle of nephrons + collecting duct
capsule
external layer of kidney
dense, fibrous structure
protection
pyramid
within medulla
pyramidal shapes formed by tubes conducting fluid towards urethra
renal columns
regions of medulla in between pyramids
lobe
includes individual pyramid + half of renal column on either side
+ cortex above
renal papilla
apex of pyramid
where tubes drain into; leads to calyx
calyx
collecting structure
minor collects from renal papilla →major → renal pelvis
renal pelvis
open space
connected to all calyces
drains into urethra
renal hilum
where structures enter/exit kidney
kidney blood supply
renal artery carries oxygenated blood → branches into 5 segmental arteries (feed into each of 5 segments in kidneys) → branch into interlobar arteries = travel into spaces between lobes → branch at base of each lobe into two arcuate arteries = supply base of pyramid from both sides → interlobular arteries supply cortex
veins parallel arteries; carry deoxygenated blood; run anterior to artery (runs anterior to pelvis)
cortical circulation
interlobular arteries extend into cortex between lobules → branch into afferent arterioles = form renal corpuscles in nephrons
nephron
basic functional unit of kidney
~1 million/kidney
(only need ~10% to be functional)
anatomy of nephron
renal corpuscle = capillary bed → PCT → Loop of Henle (thick desc → thin desc → thin asc → thick asc) → DCT → collecting tubule → into papilla
function of nephron
blood is filtered in renal corpuscle
blood cells + large proteins retained by filter
low molecular weight proteins, ions, metabolites, dissolved wastes pass through into PCT
water, ions, and useful substances are reabsorbed into renal tubule
cortical nephrons
mainly in cortex
small part of loop of Henle sits in medulla
efferent arteriole forms capillary bed around tubules
juxtamedullary nephrons
sits at junction between cortex + medulla
loop of Henle extends deep into medulla
important for regulation of urine concentration
vasa recta carry away water to preserve salt gradient
renal corpuscle
afferent arteriole carries blood into corpuscle → forms glomerulus = capillary bed
blood filters through filtration layer into Bowman’s space → PCT
= filtrate
mesangial cells
cells within capillary bed
Bowman’s capsule
outer membrane of corpuscle
parietal layer
podocytes
cells covering surface of glomerulus capillaries
visceral layer
filtration layer
- fenestrations of endothelial cells
- basal lamina of glomerulus
- podocyte filtration slits
proximal convoluted tubule
reabsorption of organic nutrients, ions, water as required by body
cells have villi + microvilli projecting into lumen = ↑ SA for absorption
loop of Henle
thin limb = reabsorption of water (thin wall = diffusion)
thick limb = reabsorption of Na+ + Cl- (proteins require to transport)
distal convoluted tubule
secretion of ions, acid, toxins
variable reabsorption of ions + water
under control of aldosterone = what passes through membrane
collecting duct
variable reabsorption of water + ions
under control of ADH = influences permeability of tube wall
papillary duct
delivers urine to calyces
urine concentration
movement of filtrate down loop of Henle in juxtamedullary nephrons → create salt gradient
low [salt] in CD filtrate causes water to be reabsorbed
allows retention of water + elimination of solutes
juxtaglomerular apparatus
macula densa, juxtaglomerular cells, arterioles
increases filtration rate + elevates blood pressure
macula densa
cells lining distal tubule near arterioles
compare electrolyte concentration between eff and aff arterioles
juxtaglomerular cells
smooth muscle cells around afferent arterioles
can constrict to attenuate blood flow = change pressure
secrete renin → elevates blood pressure
urinary tract
ureter → urinary bladder → urethra
ureter
mucosa = transitional (thick squamous) epithelium + lamina propria (vasculature)
submucosa = smooth muscle (both concentric + longitudinal)
outer connective tissue layer
peristalsis moves urine towards bladder
passes deep to vessels feeding gut but anterior to iliac vessels
pulls blood vessels from other organs to feed wall
urinary bladder
mucosa = transitional epithelium + lamina propria
submucosa
detrusor muscle
covered by visceral peritoneum
ureters enter inside of bladder at ureteral openings
lots of rugae: folds and pockets that accommodate large amount of extensibility
transitional epithelium
allows large expansion of bladder wall
trigone
triangular area between ureteral openings and neck leading to urethra
lots of receptors = sensitivity
internal urethral sphincter
mainly in males (less developed in females)
smooth muscle with circular fibers
urethra
mucosa = stratified squamous epithelium + lamina propria (lots of mucous epithelial glands)
smooth muscle
carries urine from bladder to external environment
prostate gland
only in males
inferior to bladder, around urethra
external urethral sphincter
skeletal muscle
in urogenital diaphragm
sites of ureteric constriction
ureteropelvic junction (transition from renal pelvis to ureter)
crossing of the iliac vessels (anteriorly)
ureterovesical junction (where ureter enters bladder)
kidney stones
calcification of solute-rich filtrate
very painful → rough + jagged surface pushed through narrow calyces + ureter
innervation of kidneys
symp: T10-L1
parasymp: vagus
= carries afferent signals of pain from kidney stone = referred pain in posterior wall ~L1 level
+ cross over into genitals
innervation of ureters + bladder
ureter: lower spinal levels (T11-L2)
bladder: L1-L2 (pelvic cavity)
referred pain
