1. Xue Zhou Department of Histology & Embryology, Sichuan University
Urinary System 泌尿系统
Xue Zhou
Department of Histology & Embryology,
Sichuan University

2. Function
1. Excretion metabolic waste products
2. Maintaining the balance of fluid
and electrolyte
3. Secretion of some substances

3. Composition
Kidney----main organ
Ureter
Excretory ducts Urinary bladder
Urethra

4.      Kidney 肾
Structure
bean shaped
Nephron---function unit
Parenchyma
Collecting tubule
Interstitial tissue: a little loose connective tissue

5. Renal corpuscle Nephron Renal tubule Uriniferous tubule
minor calyx
major calyx
renal pelvis
ureter
medullary ray
cortical labryinth
renal column
renal pyramid
(Medulla)
renal papilla
cortex
Cortex
Nephron
Renal corpuscle
Renal tubule
Collecting tubule
Uriniferous tubule

6. // The structural & functional unit;
Nephron 肾单位
// The structural & functional unit;
// Include renal corpuscle, proximal
tubule, thin segment , distal tubule;
// Produce urine.
Proximal straight tubule
Henle’s loop Thin segment
Distal straight tubule

7. Structure and function of each segment
① Renal corpuscle 肾小球
Function:
filtration of blood plasma to
form primary urine.

8. Structure spherical body Renal glomerulus Renal capsule Vascular pole
Urinary pole

9. Renal corpuscle, HE

10. Renal glomerulus, SEM

11. A. Renal glomerulus 肾血管球
√afferent arteriole
√efferent arteriole
Which one should be thicker? Why?
√capillary which type?
fenestrated capillary

12. Fenestrated capillary & Podocytes

13. B. Renal capsule( a double layered capsule)
肾小囊
·Parietal layer 壁层:
simple squamous epi connect
with proximal tubule
·Visceral layer 脏层:
podocytes（足细胞）, primary &
secondary process, filtration slit

14. Fenestrated capillary & Podocytes

15. Fenestrated capillary, TEM

16. Filtration barrier, TEM

17. Filtration barrier 滤过屏障
// The structure separate the cap blood
from the capsular space.
// It consists of fenestrated endothelial cell,
basement membrane & filtration slit
membrane.
// Filtrate blood plasma to form primary
urine.

19. slit
B.M
Endo.
water
cation
glucose
anion
白蛋白
protein

20. Primary urine waste products 180L/day water electrolytes
nutrients: glucose,
amino acids…
Primary urine waste products
180L/day water
electrolytes
A lot of nutrients, water, electrolytes will be reabsorbed by following segments.

21. ② Proximal tubule 近端小管
the largest, longest segment of nephron
Function:
reabsorption %H2O, NaCl,
all G, AA, proteins
excretion--- H+, NH4+…

22. Proximal convoluted tubule

23. Proximal convoluted tubule, EM

24. simple cuboidal epi with classical structure of reabsorption.
 Proximal convoluted tubule 近曲小管:
simple cuboidal epi with classical structure
of reabsorption.
EM LM
Free surface microvill,tubular pits brush border
Lateral margin lateral process unclear border
Basal end infolding,mitochondria basal striations
All above increase the surface of cell greatly,permit reabsorbing rapidly from tubule lumen and giving away reabsorbing substances to interstitial tissue quickly.

25. ③ Thin segment 细段
Small sized tubule line with simple
squamous epithelium.
Function:
urine concentration by it’s thin wall
and hyperosmat of medullary
interstitial tissue.

26. ④ Distal tubule 远端小管:
Simple cuboidal epithelium.
This segment is thinner and shorter than proximal tubule.
Function:
In the influence of aldosteron(醛固酮)
regulate the acid-base equilibrium
of body:
reabsorption Na+, Cl- and water;
excretion K+, H+, NH4+ .

27. ⑤ Collecting tubule 集合小管
Simple cuboidal or columnar epithelium.
LM: lumen--- largest
cytoplasm--- lightest
cell border--- clearest
Function:
collecting urine of nephron, regulating the
concentration of urine as distal tubule.

28. Juxtaglomerular apparatus 球旁复合体

29. *Modified smooth muscle cells in the wall of afferent arteriole.
①Juxtaglomerular cell 球旁细胞
*Modified smooth muscle cells in the
wall of afferent arteriole.
*Large and pale epitheoid cells
*Secretion rennin(肾素) into blood for
regulation the blood pressure and the
function of distal & collecting tubule.

30. ②Macula densa 致密斑
*The epithelium of distal tubule become
columnar and form a elliptic spot.
*Sense the urine Na+ concentration in
lumen & influence the function of
Juxtaglomerular cell.

31. ③Extraglomerular mesangial cell 球外系膜细胞
A group of cells, lying between
the macula densa & afferent,
efferent arterioles.
The function is not well understood.

32. I. The Development of Urinary System
nephrotome,nephrogenic cord urogenital sinus
pronephros
mesonephros urinary
bladder and urethra
metanephros (epithelium)
(permanent kidney)

34. The Metanephros
5th week
caudal to the mesonephros
permanent
functional
ureteric bud
two sources
metanephric mesoderm

38. mesonephric duct metanephric mesoderm
ureteric bud metanephric tubules
ureter, renal tubules
renal pelvis,
major & minor calyces,
collecting tubules one end another end
communicate invaginated
by capillaries
collecting tubule nephron

39. Horse-shoe Kidney
Ectopic Kidney

40. Ectopic Kidney

41. Horse-shoe kidney

42. Polycystic kidney

43. Polycystic kidney

44. Double Ureters

45. Double Ureters

46. Double ureters