1. Urinary system 2 Kidneys. 2 Kidneys. 2 ureters. 2 ureters. Urinary bladder. Urinary bladder. Urethera. Urethera.

2. Kidney Cortex---Dark brown and granular. Cortex---Dark brown and granular. Medulla---6-12 pyramid-shape regions (renal pyramids) Medulla---6-12 pyramid-shape regions (renal pyramids) The base of pyramid is toward the cortex (corticomedullary border) The base of pyramid is toward the cortex (corticomedullary border) The apex (renal papilla) toward the hilum that perforated by 12 openings of the ducts of Bellini in region called area cribrosa. The apex is surrounded by minor calyx. The apex (renal papilla) toward the hilum that perforated by 12 openings of the ducts of Bellini in region called area cribrosa. The apex is surrounded by minor calyx. Pyramids are separated by cortical columns of Bertin Pyramids are separated by cortical columns of Bertin 3or4 minor calyces join to form 3or 4 major calyces that form renal pelvis. 3or4 minor calyces join to form 3or 4 major calyces that form renal pelvis.

3. A hemisected vew of the kidney

4. Cortical arch Renal corpuscles (red dots). Renal corpuscles (red dots). Convoluted tubules (cortical labyrinth). Convoluted tubules (cortical labyrinth). Medullary rays (cortical continuation of pyramids). Medullary rays (cortical continuation of pyramids). NB. Lobe of the kidney is formed of : NB. Lobe of the kidney is formed of : a- Renal pyramid. a- Renal pyramid. b-Cortical columns. b-Cortical columns. c-Cortical arch c-Cortical arch *Each medullary ray with part of the cortical labyrinth surrounding it form kidney lobule.

6. Uriniferous tubule

7. Is the functional unit of the kidney. Is the functional unit of the kidney. Is formed of: Is formed of: 1- Nephron. 1- Nephron. 2-Collecting tubule. 2-Collecting tubule. They are densely packed. They are densely packed. They are separated by thin stroma and basal lamina. They are separated by thin stroma and basal lamina.

8. Nephron There are 2 types: There are 2 types: a-Cortical nephrons. a-Cortical nephrons. b-Juxtamedullary nephrons. b-Juxtamedullary nephrons. *It is formed of : 1-Renal corpuscle. 1-Renal corpuscle. 2-Proximal tubule. 2-Proximal tubule. 3-Thin limbs of Henle ’ s loop. 3-Thin limbs of Henle ’ s loop. 4-Distal tubule 4-Distal tubule

9. Renal corpuscle Glomerulus (tuft of fenestrated capillaries) Glomerulus (tuft of fenestrated capillaries) Bowman ’ s capsule (Parietal layer, urinary or glomerular space and visceral layer or podocytes). Bowman ’ s capsule (Parietal layer, urinary or glomerular space and visceral layer or podocytes). Mesangial cells (intraglomerular & extraglomerular). Mesangial cells (intraglomerular & extraglomerular).

10. Renal cortex Renal corpuscle

16. Filtration barrier Endothelial wall of the capillaries. Endothelial wall of the capillaries. The basal lamina (inner and outer laminae rarae and middle lamina densa). The basal lamina (inner and outer laminae rarae and middle lamina densa). Visceral layer of Bowman ’ s capsule (podocytes) Visceral layer of Bowman ’ s capsule (podocytes) Podocytes have primary (major) processes and secondary (minor) processes (pedicles). Podocytes have primary (major) processes and secondary (minor) processes (pedicles). Between pedicles (on the surface of capillaries) there are filtration slits that have slit diaphragm Between pedicles (on the surface of capillaries) there are filtration slits that have slit diaphragm

18. Proximal tubule It has 2 regions: It has 2 regions: 1-Pars convoluta (Proximal convoluted tubule). 2-Pars recta (descending thick limb of Henle ’ s loop). It is composed of simple cuboidal epith.with acidophilic cytoplasm. The cells have striated or brush border and lateral interdigitations. They have well-defined basal lamina.

19. Cell of proximal tubule

20. Thin limb of Henle ’ s loop It has 3 regions: It has 3 regions: 1-Descending thin limb. 1-Descending thin limb. 2-Henle ’ s loop. 2-Henle ’ s loop. 3-Ascending thin limb. 3-Ascending thin limb. NB. It is longer in juxtamedullary nephron than in cortical nephron. * It is composed of simple squamous epith.

21. Renal medulla

22. Distal tubule It has 3 regions: It has 3 regions: 1-Ascending limb of Henle ’ s loop (low cuboidal epith.). 2-macula densa (tall &narrow cells). 3-Pars convoluta (distal convoluted tubule) formed of low cuboidal epith. NB. Because distal convoluted are much shorter than proximal convoluted tubules, any section of renal cortex presents many more sections of proximal convoluted tubules. *Distal tubules drain into collecting tubules. *Aldosterone hormone increase the active rebsorbtion of sodium from the lumen of tubule into interstitium.

23. Distal tubule cells.

24. Juxtaglomerular apparatus

25. It has 3 components: It has 3 components: A-The macula densa of distal tubule. A-The macula densa of distal tubule. B-Juxtaglomerular cells of afferent glomerular arteriole (modified smooth muscle of tunica media). They secrete renin,angiotensin-converting enzyme and angiotensin. B-Juxtaglomerular cells of afferent glomerular arteriole (modified smooth muscle of tunica media). They secrete renin,angiotensin-converting enzyme and angiotensin. C-The extraglomerular mesangial cells. C-The extraglomerular mesangial cells.

26. Juxtaglomerular apparatus

27. Collecting tubules Are composed of simple cuboidal epithelium. Are composed of simple cuboidal epithelium. They aren ’ t part of nephron. They aren ’ t part of nephron. They have 3 regions: They have 3 regions:1-Cortical.2-Medullary. 3-Papillary (ducts of Bellini) they open in area of cribrosa. *They are formed of: a-principle cells. And b-intercalated cells. And b-intercalated cells. *They are impermeable to water except in presence of antidiuretic hormone.

28. Cells of collecting tubule

29. Renal interstitium It is a very flimsy, scant amount of CT contains. It is a very flimsy, scant amount of CT contains. 1-Fibroblasts. 1-Fibroblasts. 2-Macrophages. 2-Macrophages. 3-Interstitial cells (their nuclei are elongated and they contain lipid droplets). They secrete medullipin I, which is converted in the liver into medullipin II, that lowers blood pressure. 3-Interstitial cells (their nuclei are elongated and they contain lipid droplets). They secrete medullipin I, which is converted in the liver into medullipin II, that lowers blood pressure.

30. Calyces Each calyx accepts urine from the renal papilla of a renal pyramid. Each calyx accepts urine from the renal papilla of a renal pyramid. They are lined with transitional epith., lamina propria and smooth muscle. They are lined with transitional epith., lamina propria and smooth muscle. Minor calyces merge to form major calyces (with same lining tissue as minor calyces). Minor calyces merge to form major calyces (with same lining tissue as minor calyces). Major calyces open into renal pelvis. Major calyces open into renal pelvis.

31. Renal papilla and minor calyx.

32. Ureter 1.Mucosa is formed of transitional epith. And lamina propria. 1.Mucosa is formed of transitional epith. And lamina propria. 2.Muscularis (muscular coat) is formed of 2 layers of smooth muscle: 2.Muscularis (muscular coat) is formed of 2 layers of smooth muscle: A-Inner longitudinal. B-Outer circular. * 3.Adventitia (fibrous CT covering).

33. Ureter

34. Urinary bladder It has the same structure as the ureter EXCEPT: It has the same structure as the ureter EXCEPT: The dome-shaped cells have plaques (rigid, thickened regions of plasmalemma) The dome-shaped cells have plaques (rigid, thickened regions of plasmalemma) Between plaques there are normal cell membrane (interplaque regions). Between plaques there are normal cell membrane (interplaque regions). It has 3 layers of smooth muscle, inner and outer longitudinal and middle circular. It has 3 layers of smooth muscle, inner and outer longitudinal and middle circular. Its outer covering is serosa. Its outer covering is serosa.

35. Urinary bladder

36. Female Urethra Female urethra is short and lined by : Female urethra is short and lined by : 1-Transitional epith. Near the bladder. 2-Pseudostratified columnar epith. And stratified squamous non-keratinized epith. 3-Subepth.fibroelastic CT that contains glands of Littre (mucus secreting glands). 4-Smooth muscle (inner longitudinal and outer circular layer).

37. Male Urethra It is long and is divided into 3 regions: It is long and is divided into 3 regions: 1-The prostatic urethra — lined with transitional epith. 2-Membranous urethra---lined with pseudustratified columnar and stratified columnar epith. 3-Penile (spongy) urethra---lined with pseudostratified columnar, stratified columnar and stratified squamous non-keratinized epith. * Its lamina propria contains mucus secreting glands of Littre.