Urinary System: Division Of Histology And Embryology

Urinary system Division of histology and embryology

Components 

Kidneys



Ureters



Bladder



urethra

Functions of kidneys Regulate the fluid and electrolyte balance of body  Remove waste products of metabolism from body  Function as endocrine organs: 

Synthesize and secrete erythropoeitin , renin Activate vitamin D

Kidney

Kidney structure capsule

Renal column

Medullary ray hilum Renal medulla (pyramid) Renal pelvis

Major calyx

ureter

Minor calyx Renal cortex

Kidney

(HE)

Renal cortex: Cortical labyrinth Medullary ray

Renal medulla

Renal cortex (HE)



Cortical labyrinth



Medullary ray

Kidney lobe and kidney lobule 

A kidney lobe: A medullary pyramid and the associated cortical tissue



A kidney lobule: A medullary ray and the surrounding cortical labyrinth

Kidney 

Covering membrane: Connective tissue capsule



Parenchyma:



Interstitium:

Uriniferous tubules Connective tissue Blood vessels,Lymph vessels Nerves…

Uriniferous tubule Renal corpuscle

(components)

Proximal convoluted tubule

Nephron

Renal Henle’s loop Uriniferous

tubule

tubule Distal convoluted tubule Collecting tubule

Henle’s loop

Thick descending limb

Henle’s loop

Thin descending limb Thin segment

Thin ascending limb

Thick ascending limb

Cortical nephron and juxtamedullary nephron

Cortical nephron Juxtamedullary nephron Renal corpuscle nephron Renal tubule

Cortex (Cortical labyrinth)

Renal corpuscle Vascular pole

Glomerulus

Bowman’s capsule

Urinary pole

Glomerulus (SEM) Afferent arteriole Effernt arteriole

Renal corpuscle (SEM)

Renal corpuscle (HE)

Renal corpuscle Glomerular capillary: fenestrated capillary Bowman’s capsule: parietal layer visceral layer

Podocyte (SEM) primary process secondary process (pedicel) slit pore filatration slit membrane

Mesangium

(mesangial cell)

Function: remove the particles and clean the membrane

provide support of the capillary wall

Filtration barrier 1) Endothelium of the glomerular capillaries Lamina rara interna

2) The basement membrane Lamina densa

Lamina rara externa

3) The filtration slit membrane

Filtration barrier

Renal tubule Distal convoluted tubule

Proximal convoluted tubule

Henle’s loop

Proximal convoluted tubule

Proximal convoluted tubule A simple cuboidal epithelium Cell shape: cuboidal cell with brush border Nucleu: small,round,located in the base Cytoplasm: strong acidophilic

Proximal convoluted tubule cell ultrastructure Microvilli Canaliculi and vesicles Membrane folds Mitochondria Natrium/kalium ATPase Cell junction Membrane interdigitation

Proximal convoluted tubule

Proximal convoluted tubule (SEM)

Proximal convoluted tubule Functions: Urine absorption Water and electrolyte absorption Amino acid,sugar and small protein absorption Large protein absorption Secrete Hydrogen ion, Ammonia, creatinine

Henle’s loop

Thick descending limb

Henle’s loop

Thin descending limb Thin segment

Thin ascending limb

Thick ascending limb

Thick descending limb

Thin segment A simple squamous epithelium

Thick ascending limb

Distal convoluted tubule A simple cuboidal epithelium Cell shape: small cuboidal cell lacking brush border Nucleu: small,round, located in medium Cytoplasm: less acidophilic

Distal convoluted tubule cell ultrastructure

Few microvilli Few canaliculi and vesicles Few interdigitation Extensive membrane folds Numerous mitochondria

Distal convoluted tubule functions Absorb Na and secrete K Secrete Hydrogen and Ammonium into tubular urine

Hormone regulation Aldosterone: increase the absorption of Na and water increase the secretion of K Antidiuretic hormone: increase the absorption of water

Collecting tubule and duct Arched collecting tubule Cortical collecting tubule Medullary collecting tubule Papillary duct A simple epithelium: Squamous cuboidal columnar high columnar

Cortial collecting tubule

Papillary duct

Collecting tubule cell ultrastructure Few microvilli Few organells No interdigitation No membrane fold

Collecting tubule Function Absorb Na and water Secrete K

The activity is controlled by the aldosterone and ADH

Cortex (Cortical labyrinth)

medulla

Renal tubules

Juxtaglomerular complex

1. juxtaglomerular cell 2. Extraglomerular mesangial cell 3. Macula densa

Juxtaglomerular complex Juxtaglomerular cell Origin: smooth muscle cell of the afferent arteriole Secretion: renin (hormone) Angiotensinogen angiotensinI angiotensinII aldosterone

Juxtaglomerular complex macula densa Origin: part of the distal tubule wall Function: sensitive to the Cl content of tubular fluid

Juxtaglomerular complex

Extraglomerular mesangial cell

Blood supply of kidney Renal artery Interlobar arteries Arcuate arteries Interlobular arteries

Blood supply of kidney interlobular artery afferent arteriole glomerulus efferent arteriole

(cortical nephron) efferent arteriole ↓ postglomerular capillary ↓ Interlobular vein

(juxtamedullary nephron) efferent arteriole→ postglomerular capillary straight arteriole

Interlobular vein straight venule

Blood supply of kidney Renal artery Interlobar arteries Arcuate arteries Interlobular arteries

Renal interstitium Interstitial cell: Medullipin-Ⅰ

liver

Medullipin-Ⅱ Blood pressure

Ureter 

Mucosa



Muscular layer



adventitia

Ureter mucosa Epithelium: transitional epithelium Lamina propria: connective tissue

Bladder

Bladder

Transitional epithelium