Structure of the Urinary System

1. Structure of the Urinary System Jun Zhou （周俊） Department of Histology & EmbryologySchool of Medicine,Zhejiang University 20151201 1

2. 1. Overview • Anatomy of the Urinary System • 1) Kidneys • 2) Blood Circulation • 3) Ureters, Urinary Bladder, and Urethra • 3. Histology of the Urinary System • 1) Kidneys • 2) Nephrons and Blood Circulation • Cortex • Medulla • Juxtaglomerular apparatus • 4. Function of the Urinary System 2

3. Anatomy of the Urinary System 3

4. Functions of the Kidney • Regulation of body fluid osmolality • Regulation of electrolyte and water • Excretion of waste products • Regulation of acid and base • Production of hormones: Erythropoietin, Kinins and Renin, Prostaglandins，1,25-dihydroxycholecalciferol

5. Kidney • Position: in retroperitonealspace, • both side of spinal column • upper end lower end • left T11 L2 • rightT12 L3 T11 T12 L1 L2 L3

6. Relation: anteriorly— • left: stomach, spleen, pancreas, left colic flexure • right: liver, right colic flexure, descending part of duodenum Relation of the kidney: anterior view

7. Anatomy of the Urinary System – Kidneys 7

8. Anatomy of the Urinary System – Kidneys 8

9. Anatomy of the Urinary System – Kidneys Histological image of a kidney from a stillborn child. (It is small enough to section and photograph in its entirety.) SOURCE: Elsevier. Young et al. Wheater’s Functional Histology 5e – www.studentconsult.com 9

10. sup. sup. sup. and ant. post. inf. and ant. inf. inf. • Blood vessels and segments of kidney: ---Renal a. ---anterior and posterior trunks---5 segmental aa. ---5 segments: superior segment superior-anterior segment inferior-anterior segment inferior segment posterior segment

11. Anatomy of the Urinary System – Kidneys – Blood Circulation 11

12. Anatomy of the Urinary System – Kidneys – Blood Circulation 12

13. Anatomy of the Urinary System – Kidneys – Blood Circulation RENAL CORTEX Interlobular artery Afferent arteriole Glomerular capillary Efferent arteriole Interlobular vein Peritubular capillary Arcuate artery Arcuate vein Vasarecta Interlobar artery Interlobar vein RENAL MEDULLA Segmental artery RENAL PELVIS Renal artery START HERE Renal vein END HERE 13

14. Renal blood circulation （1）extensive, 1200ml/min （2）glomerular Cap. and peritubular Cap. network （3）Vasa recta associated with the Henle loops

15. Histology of the Urinary System – Kidneys A A B B 15

16. Histology of the Urinary System – Kidneys – Nephrons A A The structure of the nephron: B Collecting duct（集合管） 16

17. Histology of the Urinary System – Kidneys – Nephrons – Types 2 types of nephrons: 17

18. Histology of the Urinary System – Kidneys – Cortex: Renal Corpuscle B A A Each renal corpuscle is about 200 micrometers in diameter. B 18

19. Histology of the Urinary System – Kidneys – Cortex: Renal Corpuscle 19

20. Histology of the Urinary System – Kidneys – Cortex: Renal Corpuscle 20

21. Histology of the Urinary System – Kidneys – Cortex: Renal Corpuscle Capillary loops in the glomerulus. A A Surface of glomerulus – SEM. 21

22. Histology of the Urinary System – Kidneys – Cortex: Renal Corpuscle More detail on podocytes. A A 22

23. Histology of the Urinary System – Kidneys – Cortex: Renal Corpuscle Function of the Renal corpuscle: 23

24. Histology of the Urinary System – Kidneys – Cortex: Renal Corpuscle A B A Filtration system or barrier: Section through capillary of glomerulus. B 24

25. Histology of the Urinary System – Kidneys – Cortex: Renal Corpuscle The structure between capillary loops in the glomerulus: 25

26. Histology of the Urinary System – Kidneys – Cortex: Proximal Convoluted Tubule B A Proximal convoluted tubule： A B 26

27. Histology of the Urinary System – Kidneys – Cortex: Distal Convoluted Tubule Distal Convoluted Tubule: 27

28. Histology of the Urinary System – Kidneys –Collecting Ducts Collecting ducts: B 28

29. Histology of the Urinary System – Kidneys – Nephrons – Medulla: Renal Papilla A Renal papilla: Cross-section through renal papilla. B 29

30. Histology of the Urinary System – Kidneys – JGA Juxtaglomerular apparatus (JGA)（肾小球旁器） B A A B B 30

31. JG cells（球旁细胞） • Modified smooth muscle cells • Are located primarily in the wall of afferent arterioles • Synthesize renin(肾素）

32. Macula densa cells（致密斑） • tall, narrow,closely packed epi.cells of the distal tubule • elongated, closely packed nuclei (macula densa) • monitor the osmolarity and volume of the distal tubule and transmit information via gap junction(缝隙连接)

33. Extraglomerular mesangial cells (lacis cells) • (球外系膜细胞, 极垫细胞) • lie btw. the afferent and efferent arterioles • transmit information

34. Function: maintains blood pressure

35. Ureter （输尿管） • Position: From kidney to urinary bladder. • Eternal features: muscular canal, 25~30cm in length 3 parts---- abdominal part pelvic part intramural part 3 constrictions---- point conjoined with renal pelvis; point crossed with iliac artery; intramural part.

36. Urinary bladder （膀胱） • Position: located in the anterior poisition of the lesser pelvic cavity • Relations:

37. The external features • pyramid shape— • apex • fundus • body • neck • The structures • urinary trigone（膀胱三角） • ureteric orifices, • internal urethral orifice • interureteric fold（输尿管间襞）

38. Urinary bladder Mucosa：transitional epi.+lamina propria Muscularies：smooth muscle adventitia：CT，serosa（apical area)

39. The end. 39