the urinary system Flashcards
ureters
transport urine from kidneys to urinary bladder
urinary bladder
temporary storage reservoir for urine
urethra
transports urine out of body
kidneys
maintain the body’s internal environment
- regulating total water volume and total solute
- regulating ions concentrations in extracellular fluid (ECF)
- ensuring long-term acid-base balance
- excreting metabolic wastes, toxins, drugs
- producing erythropoietin (regulating rbc) and renin (regulates BP)
- activating vitamin d
- carrying out gluconeogenesis if needed
retroperitoneal
in the superior lumbar region
-right kidney is crowded by liver and is lower than left
adrenal gland
sits atop each kidney
-convex lateral surface
renal cortex
granular appearing superficial region
renal medulla
deep to cortex composed of cone-shaped medullary pyramids
papilla
tip of pyramid points internally
renal pelvis
funnel shaped tube continuous with ureter
minor calyces
cup shaped areas that collect urine draining from pyramidal papillae
major calyces
areas that collect urine from minor calyces
- empty urine into renal pelvis
urine flow
renal pyramid –> minor calyx –> major calyx –> renal pelvis –> ureter
pyelitis
infection of renal pelvis and calyces
pyelonephritis
infection or inflammation of entire kidney
- infections in females are usually caused by fecal bacteria entering urinary tract
- severe cases can cause swelling of kidney and abscess formation and pus may fill renal pelvis
renal arteries
deliver about one fourth of cardiac output to kidneys each minute
arterial flow
renal –> segmental –> interlobar –> arcuate –> cortical radiate
venous flow
cortical radiate –> arcuate –> interlobar –> renal veins
nephrons
are the structural and functional units that form urine
- renal corpuscle
- renal tubule
renal corpuscle
glomerulus
glomerular capsule
glomerulus
- tuff of capillaries composed of fenestrated epithelium (lots of holes colander)
- Allows for efficient filtrate formation
filtrate: plasma-derived fluid that renal tubules process to form urine
glomerular capsule
cup-shaped, hollow structure surrounding glomerulus
2 layers:
* parietal layer- simple squamous epithelium
* visceral layer - clings to glomerular capillaries, branching epithelial podocytes
- extensions terminate in foot processes
- filtration slits between foot processes allow filtrate to pass into capsular space
renal corpuscle
- proximal convoluted tubule
- nephron loop (loop of henle)
- distal convoluted tubule (drains into collecting duct)
- proximal convoluted tubule
simple cuboidal epithelial cells with dense microvilli that form brush border
- functions in reabsorption and secretion
- nephron loop (loop of henle)
u-shaped structure consisting of two limbs
* descending limb; simple squamous epithelium
* ascending limb; cuboidal or columnar cells
- distal convoluted tubule
simple cuboidal cells
function more in secretion than reabsorption
collecting duct
- receive filtrate from many nephrons
- ducts fuse together to deliver urine through papillae into minor calyces
1. principal cells: maintain water and Na+ balance
2. intercalated cells: help maintain acid-base balance of blood
2 major groups of nephrons
- cortical nephrons
- make up 85% of nephrons - juxtamedullary nephrons
- long nephron loops deeply invade medulla
- important in production of concentrated urine
renal tubules are associated with 2 capillary beds
- capillaries of the glomerulus
- capillaries are specialized for filtration
- different from other capillary beds because they are fed and drained by the arteriole
- afferent arteriole arises from cortical radiate arteries
- efferent arteriole feed into either peritubular capillaries or vasa recta
Blood pressure in glomerulus is high because; afferent arterioles are larger in diameter than efferent arterioles - peritubular capillaries
- low pressure, porous capillaries adapted for absorption of water and solutes
- arise from efferent arterioles
- cling to adjacent renal tubes in cortex
- empty into venules
- vasa recta; form concentrated urine
