Urinary system Flashcards
Location of kidneys
lower thoracic and upper lumbar region
behind mesentery
Paranephric fat
located external to the renal fascia- the extraperitoneal fat of the lumbar region most obvious posterior to the kidney
Renal fascia
a membranous layer that encloses the kidneys, suprarenal glands, and perinephric fat, sends collagen bundles thru the connective tissue
Perinephric fat
surround the kidneys and their vessels
completely encases the kidneys
Suprarenal glands (adrenal glands)
Positioned between the diaphragm and superomedial aspects of kidneys
enclosed by renal fascia
right gland- contact the liver and IVC
Left gland-contacts the stomach, spleen, and pancreas
Hilum of kidney
the concave surface of the kidney where vessels and nerves enter and exit
renal vein, renal artery, renal pelvis, and ureter
Medulla of kidney
consists of 6+ renal pyramids which contain urine-collecting tubules
process filtrate, concentrate, and excretion
Cortex
composed of nephrons responsible of urine production thru filtration, resorption, and secretion
Where do the minor and major calices and renal pelvis drain?
ureters
Renal arteries
arise at the IV disk level between L1 and L2
located posterior to the renal veins
Renal veins
the longer left renal vein passes anterior to the aorta
drains into the IVC
How much blood filters thru the kidneys each minute?
1 liter
Nephrons
2 parts
corpuscles- site of filtration
tubules-responsible for resorption and secretion
Cortical nephron
has a short nephron loop and glomerulus further from the corticomedullary junction
efferent arteriole supplies peritubular capillaries
Juxtamedullary nephron
Has a long nephron loop and glomerulus closer to the corticomedullary junction
efferent arteriole supplies vasa recta
Urine excretion
urine leaves the collecting system
enters the renal pelvis
the remainder of the urinary system transports, stores, and eliminates urine
Ureters
oblique entry into the bladder prevents the backflow of urine as any increase in pressure within the bladder compresses its wall and closes the distal ureters
The ureters are normally constricted in 3 places
at the junction with the renal pelvis
site of crossing the pelvic brim
passage thru the bladder wall
What muscle is in the bladder wall
detrusor
3 layers of smooth muscle
Location of urinary bladder
retroperitoneal, enveloped by loose connective tissue, superior surface covered by peritoneum
Parts of bladder
apex-anterior end
fundus
body-lies between the apex and fundus
neck
Bladder function
stores and expels urine
Urethra
a thin-walled tube that extends from the urinary bladder to the exterior of the body
Female urethra
3-4 cm in length
Passes from the internal urethral orifice of the bladder to the external urethral orifice in the vestibule of the vagina
musculature surrounding the internal urethral orifice not organized into an internal sphincter
Trigone (female urethra)
smooth triangular region defined by the ureteric orifices and the internal urethral orifice
Male urethra
18-22 cm in lenth
Divided into 4 parts:
intramural (preprostatic)
prostatic urethra
intermediate (membranous) urethra
spongy (penile) urethra
Intramural (preprostatic)
surrounded by an internal urethral sphincter composed of sympathetically innervated smooth muscle
Prostatic urethra
Passes thru the prostate gland
Intermediate (membranous) urethra
surrounded by the somatically innervated external urethral sphincter
Spongy (penile) urethra
passes thru the length of the penis
UTIs
women are 30x more likely to get UTIs than men
1. length of the urethra
2. placement of the urethra
3. sexual contact
4. the skin of the perineum in women
5. other factors like contraception
Effects of the sympathetic nervous system on the urinary tract
vasoconstriction of renal vessels slows urine formation
internal sphincter of bladder contracted to maintain urinary continence
Effects of parasympathetic nervous system on the urinary tract
inhibits contraction of internal sphincter of bladder
contracts detrusor muscle of bladder wall, cause urination
Innervation of the kidneys and ureters
nerves to the kidneys and ureters arise from the renal nerve plexus and consist of sympathetic, parasympathetic, and visceral sensory fibers
How is the renal plexus supplied?
abdominopelvic splanchnic nerves
Pyelonephritis
an infection of the kidneys that has spread from the renal pelvis and calyces to the entirety of the kidney
Renal transplant
Site for the transplanted kidney is the iliac fossa of the greater pelvis, where it is firmly supported and short lengths of renal vessels and ureters are required to
Renal and ureteric calculi
excessive distension of the ureter due to a renal calculus (kidney stone) cause severe intermittent pain (ureteric colic)
