Urinary system
General outline
? component
urinary organs,kidneys
micturition organs,ureter,bladder and urethra
? function
? discharge metabolite
? regulate the balance of water and electrolyte
? endocrine function,renin,erythropoietin,
prostaglandin
Renal anatomic structure
? Fibrosa
? Parenchyma
Cortex
Cortical labyrinth
Medullary ray
Medulla
Renal pyramids
Renal columns
Renal histological structure
? nephron
Renal corpuscles
? collecting duct
? juxtaglomerular apparatus
Renal tubules
Glomerulus
Bowman’s capsule
Kidney
Renal cortex Renal medulla
Structure of Renal corpuscle:
Glomerulus
afferent arteriole
capillary network
mesangial cells
efferent arteriole
Bowman’s
capsule
parietal layer,simple squamous Epi.
capsular cavity,filtrate
visceral layer,podocytes
(primary and secondary processes,slit membrane)
Renal
corpuscle
Podocyte
Renal corpuscle Glomerulus
Functions of Renal corpuscle:
? Produce filtrate (primary urine)
? Filtration membrane
fenestrated endothelium
basement membrane
slit membrane of podocyte(filtration barrier)
? relevant factors of filtrate
molecular weight
charges
Filtration
membrane
Renal tubules:
proximal
convoluted tubule
straight tubule
thin segment
distal
straight tubule
convoluted tubule
Henle’s loops
Proximal tubule
? LM,simple cuboidal or pyramid Epi,
acidophilic cytoplasm
no discrete cell margin;
brush border;
longitudinal striation
? Location,cortical labyrinth
Convoluted segments of proximal
and distal tubules
?EM,apical canaliculi and vesicles
numerous lysosomes,Mi.
many lateral interdigitations
microvilli on the surface
membrane invaginations
abundant Na+-K+ATPase
? Function
? reabsorb water,glucose,amino acid,
protein,vitamin and inorganic salts etc,
? secrete ammonia and some metabolic
substances
thin segment
? location,medullary ray and renal pyramids
? LM,simple squamous Epi.; pale cytoplasm,
? EM,a few microvilli; less organelles
? Function,water,and ions pass through easily
Thin segment and straight
segment of distal tubule
Distal tubule
? location,medullay ray and renal pyramids
? LM,simple cuboidal Epi;
clear cell boundary;
pale cytoplasm;
nuclei near lumen;
without brush border;
have longitudinal striation
? EM,a few microvilli;
many membrane invagination;
many mitochondria;
abundant Na+-K+ATPase
? Function,reabsorb Na+ and water;
excrete K+; secrete NH3
Distal straight tubules and
collecting tubules
Convoluted segments of proximal
and distal tubule
Collecting tubules:
? location,medullary ray and renal pyramids
? components,arched collecting tubules;
straight collecting tubules;
papillary ducts
? simple cuboidal Epi simple columnar Epi.,
papillary ducts line tall columnar Epi;
pale staining; distinct borders;
rare microvilli and Mi.
? function,similar to that of distal convoluted
tubules
Straight segment of distal
tubule and collecting tubule
Juxtaglomerular apparatus:
? located in a triangle area at the vascular pole of
the renal corpuscles
? consist of juxtaglomerular cells,macular densa
and extraglomerular mesangial (polar cushion)
cells
? function,control water and electrolyte balance;
regulate blood pressure;
produce erythropoietin
Juxtaglom
-erular
apparatus
Juxtaglomerular cells
? smooth muscle cells of the afferent arteriole
transform into the epithelial cells
? cytoplasm,a few myofibrils;
PAS-positive granules contained renin;
abundant RER,ribosomes and
well developed Golgi apparatus;
? function,secrete renin and erythropoietin
Juxtaglomerular
cell
Macular densa
? transformed from the cells of distal tubule
which near the vascular pole of the renal corpuscle
? the cells become taller and narrow,arranged
compactly; pale cytoplasm; nuclei located at the
apex
? a chemical (Na+ ) sensor
Macular densa
Extraglomerular mesangial cells
? resemble the intraglomerular mesangial cells
? gap junctions between the component of the
juxtaglomerular apparatus
? transmit information
Features of renal blood circulation
? blood flow is large
? two sets of capillary network
? the diameter of afferent arterioles is larger
than that of efferent,so as to facilitate filtration
?the vasa recta are parallel to the Henle’s loop,so
aid water reabsorption and urine concentration
Blood vessels
of kidney
Micturition organs
(ureter,bladder,)
? mucosa
Epi,transitional Epi
Lamina propria,L.C.T.
? muscle layer,smooth muscle
? adventitia,fibrosa
serosa
Bladder
Ureter
General outline
? component
urinary organs,kidneys
micturition organs,ureter,bladder and urethra
? function
? discharge metabolite
? regulate the balance of water and electrolyte
? endocrine function,renin,erythropoietin,
prostaglandin
Renal anatomic structure
? Fibrosa
? Parenchyma
Cortex
Cortical labyrinth
Medullary ray
Medulla
Renal pyramids
Renal columns
Renal histological structure
? nephron
Renal corpuscles
? collecting duct
? juxtaglomerular apparatus
Renal tubules
Glomerulus
Bowman’s capsule
Kidney
Renal cortex Renal medulla
Structure of Renal corpuscle:
Glomerulus
afferent arteriole
capillary network
mesangial cells
efferent arteriole
Bowman’s
capsule
parietal layer,simple squamous Epi.
capsular cavity,filtrate
visceral layer,podocytes
(primary and secondary processes,slit membrane)
Renal
corpuscle
Podocyte
Renal corpuscle Glomerulus
Functions of Renal corpuscle:
? Produce filtrate (primary urine)
? Filtration membrane
fenestrated endothelium
basement membrane
slit membrane of podocyte(filtration barrier)
? relevant factors of filtrate
molecular weight
charges
Filtration
membrane
Renal tubules:
proximal
convoluted tubule
straight tubule
thin segment
distal
straight tubule
convoluted tubule
Henle’s loops
Proximal tubule
? LM,simple cuboidal or pyramid Epi,
acidophilic cytoplasm
no discrete cell margin;
brush border;
longitudinal striation
? Location,cortical labyrinth
Convoluted segments of proximal
and distal tubules
?EM,apical canaliculi and vesicles
numerous lysosomes,Mi.
many lateral interdigitations
microvilli on the surface
membrane invaginations
abundant Na+-K+ATPase
? Function
? reabsorb water,glucose,amino acid,
protein,vitamin and inorganic salts etc,
? secrete ammonia and some metabolic
substances
thin segment
? location,medullary ray and renal pyramids
? LM,simple squamous Epi.; pale cytoplasm,
? EM,a few microvilli; less organelles
? Function,water,and ions pass through easily
Thin segment and straight
segment of distal tubule
Distal tubule
? location,medullay ray and renal pyramids
? LM,simple cuboidal Epi;
clear cell boundary;
pale cytoplasm;
nuclei near lumen;
without brush border;
have longitudinal striation
? EM,a few microvilli;
many membrane invagination;
many mitochondria;
abundant Na+-K+ATPase
? Function,reabsorb Na+ and water;
excrete K+; secrete NH3
Distal straight tubules and
collecting tubules
Convoluted segments of proximal
and distal tubule
Collecting tubules:
? location,medullary ray and renal pyramids
? components,arched collecting tubules;
straight collecting tubules;
papillary ducts
? simple cuboidal Epi simple columnar Epi.,
papillary ducts line tall columnar Epi;
pale staining; distinct borders;
rare microvilli and Mi.
? function,similar to that of distal convoluted
tubules
Straight segment of distal
tubule and collecting tubule
Juxtaglomerular apparatus:
? located in a triangle area at the vascular pole of
the renal corpuscles
? consist of juxtaglomerular cells,macular densa
and extraglomerular mesangial (polar cushion)
cells
? function,control water and electrolyte balance;
regulate blood pressure;
produce erythropoietin
Juxtaglom
-erular
apparatus
Juxtaglomerular cells
? smooth muscle cells of the afferent arteriole
transform into the epithelial cells
? cytoplasm,a few myofibrils;
PAS-positive granules contained renin;
abundant RER,ribosomes and
well developed Golgi apparatus;
? function,secrete renin and erythropoietin
Juxtaglomerular
cell
Macular densa
? transformed from the cells of distal tubule
which near the vascular pole of the renal corpuscle
? the cells become taller and narrow,arranged
compactly; pale cytoplasm; nuclei located at the
apex
? a chemical (Na+ ) sensor
Macular densa
Extraglomerular mesangial cells
? resemble the intraglomerular mesangial cells
? gap junctions between the component of the
juxtaglomerular apparatus
? transmit information
Features of renal blood circulation
? blood flow is large
? two sets of capillary network
? the diameter of afferent arterioles is larger
than that of efferent,so as to facilitate filtration
?the vasa recta are parallel to the Henle’s loop,so
aid water reabsorption and urine concentration
Blood vessels
of kidney
Micturition organs
(ureter,bladder,)
? mucosa
Epi,transitional Epi
Lamina propria,L.C.T.
? muscle layer,smooth muscle
? adventitia,fibrosa
serosa
Bladder
Ureter
