Chapter 24 - The Urinary System Flashcards
nephros, renalis
kidney
urinary system organs
kidneys
ureters
urinary bladder
urethra
urinary system functions
maintains purity of blood and other body fluids by disposing of waste products
regulates blood volume and chemical makeup
urea
from breakdown of amino acids
uric acid
from nucleic acid turnover
creatinine
formed by creatine phosphate
Kidneys - external gross anatomy
reddish brown, bean shaped - retroperitoneal
right kidney is slightly inferior to left
lateral surface is convex, medial is concave
cushioning by fat layers
hilus
area where blood vessels, nerves pass
renal capsule
surrounds each kidney (dense CT layer)
maintains shape
Kidneys - internal gross anatomy 2 parts
cortex
medulla
cortex
outer region renal corpuscles (filters)
medulla
inner region
renal columns surround and separate the pyramids
medullary pyramids
base and apex are striated
lobes
pyramid + cortical tissue
renal sinus
space in medial portion of kidney
opening to hills
contains renal vessels, nerves, fat, renal pelvis, and calices
renal pelvis
flat tube, superior portion of ureter
calyx
extension of renal pelvis
major or minor tubes that surround papillae (apex) of the pyramids
Arteries - kidneys
rich blood supply ~20-25% of heart’s systemic output
renal arteries deliver blood to kidneys
each renal artery divides into 5 segmental arteries
each segmental artery divides into lobar arteries, which divide into inter lobar arteries
Veins - kidneys
Trace artery pathways in reverse with the exception of lobar and segmental veins
renal veins exit kidney and empty into IVC
nerves - kidneys
renal plexus
sympathetic innervation
Uriniferous tubule
structural and functional unit of the kidney
crowded together into kidney
surrounded by loose CT (interstitial CT)
2 major parts of uriniferous tubule
nephron
collecting duct
nephron
formed by a renal corpuscle, proximal convoluted tubule, loop of henle, and distal convoluted tubule
Kidneys produce urine by (3)
filtration
reabsorption
secretion
filtration
blood filtrate enters nephron
reabsorption
nutrients, water, ions are returned to blood
secretion
undesired substances move from blood to urine
Nephron parts (4)
renal corpuscle
proximal convoluted tubule
loop of Henle
distal convoluted tubule
renal corpuscle
filtration
located in cortex
glomerulus
glomerulus
ball of capillaries with many pores
surrounded by glomerular capsule (Bowman’s capsule) with capsular space
has filtration membrane
proximal convoluted tubule
located in cortex, most active in reabsorption and secretion
loop of Henle
descending limb = narrowest part
ascending limb = thick segment with a small portion of thin segment
distal convoluted tubule
located only in renal cortex
performs some reabsorption and secretion
conserves body fluids
nephron classes
cortical
juxtamedullary
cortical
located mostly in cortex
juxtamedullary
renal corpuscles are located at cortex-medulla border; have long loops of Henle
collecting tubules (ducts)
each receives urine from many nephrons
runs into medulla and combines with others to form papillary ducts, which empty into calicos
conserve body fluids; site where ADH acts
ADH
increases permeability, causing more water to be reabsorbed
Ureters
One per kidney
carry urine from kidneys to bladder
enters bladder obliquely (prevents blackflow)
distention causes contraction (peristaltic waves
Layers of the Ureters (3)
mucosa
muscularis
adventitia
Urinary bladder
collapsible, distensible, and muscular stores and eliminates urine males: anterior to rectum females: anterior to vagina and uterus full bladder holds ~1 pint of urine
Urethra
thin-walled tube, drains urine from body
composed of smooth muscle and inner layer of mucosa
internal urethral sphincter
located between bladder and urethra, involuntary control
external urethral sphincter
located at distal end of urethra, voluntary control
Micturition
emptying the bladder
detrusor muscle contracts, assisted by abdominal wall muscles
controlled by brain
Incontinence
inability to control micturition
Brain and micturition
urine accumulates
bladder wall stretches and activates stretch receptors
sensory signals sent to pons
parasympathetic neurons signal detrusor muscle to contract
Pathway
blood renal corpuscle proximal convoluted tubule loop of hence distal convoluted tuble collection tubule (duct) papillary duct minor calyx major calyx renal pelvis ureter bladder urethra micturition
Disorders of Urinary system
renal calculi (kidney stones)
pyelitis
pyelonephritis
Autosomal dominant polycystic kidney disease (ADPKD)
renal calculi
kidney stones
minerals in urine crystallize
most can pass but some become too big and obstruct a ureter
pyelitis
infection of renal pelvis and calices
pyelonephritis
infection of entire kidney
Autosomal dominant polycystic kidney disease (ADPKD)
genetic disorder
cysts (fluid-filled sacs) form and enlarge
No obvious symptoms until age 30-40
