This was done as a Student presentation on the kidney. Here following topics are covered. Macroscopic structure of the urinary system Microscopic anatomy of the urinary system Functions of the nephron Renal blood supply Kidneys and blood pressure regulation Structure of ureters and urinary bladder to perform its function Renal failure

1. Kidney Excretion & Reproduction Module Student presentation 2007/08 Batch Faculty of Medicine University of Peradeniya All what you have to know about the kidney

2. Sub topics…. 1.2.Macroscopic structure of the urinary system 3.4.5.Microscopic anatomy of the urinary system 6.7.8.Functions of the nephron 9.10.11.Renal blood supply 12,13,14.Kidneys and blood pressure regulation 15,16,17.Structure of ureters and urinary bladder to perform its function 18,19,20.Renal failure

3. MACROSCOPIC STRUCTURE OF THE URINARY SYSTEM Group No 1-2

4. URINARY SYSTEM Urinary system consists of Two kidneys Two ureters Bladder Urethra

5. KIDNEYS Size – 3 x 6 x 12 cm Weight – 130 g Shape – Bean shaped Location – Lie on the posterior abdominal wall, retroperitoneally. T12 – L3 vertebral level Right is slightly below than the left.

6. RELATIONS RIGHT KIDNEY Superiorly - Right adrenal gland Anteriorly - Right lobe of the liver, Second part of the duodenum, Hepatic flexure of the colon Posteriorly – Posterior abdominal wall muscles. (Psoas major, Quadratus lumborum, Transversus abdominis)

7. RELATIONS LEFT KIDNEY Superiorly – Left adrenal gland Anteriorly – Spleen, Stomach, Pancreas, Jejunum, Splenic flexure of the colon. Posteriorly – Diaphragm, Posterior abdominal wall muscles. (Psoas major, Quadratus lumborum, Transversus abdominis)

8. External Features Each kidney is enclosed by (from inside to outside respectively), Renal capsule – fibrous connective tissue Perirenal fat Renal fascia - fibroelastic connective tissue

9. External Features Hilum of the kidney, Concave medial border of the kidney Structures enter / leave through the hilum (from anterior to posterior), Renal vein Renal artery Ureter and Renal nerves and Lymphatics.

12. URETER 25 – 30 cm long and 3 mm in diameter Continuous with renal pelvis In abdominal cavity, lies on psoas major muscle Enters the pelvic cavity anterior to the sacroiliac joint Passes obliquely through the posterior wall of the bladder and penetrates it

13. Narrowest parts of the ureter At the junction between the pelvis and abdominal part of the ureter At the pelvic brim At the ureteric orifice of the bladder

14. BLADDER Empty bladder lies entirely in the pelvic cavity It has a shape of a flattened 3 sided pyramid.

15. Areas & surfaces Apex – sharp, pointed forward to the top of pubic symphysis. Base – triangular posterior surface facing backward in front of rectum or vagina. Trigone – lowest area of the base lies between 2 ureteral orifices and internal urethral orifice. Neck – urethral opening. Two inferolateral surfaces and superior surface.

17. MICROSCOPIC ANATOMY OF THE URINARY SYSTEM Group 3,4,5

19. Urinary bladder

22. HISTOLOGY OF THE KIDNEY

24. Kidney is made up of 10-18 lobes Lobes are made up of medullary pyramids. Bases of pyramids are enveloped by cortex. Cortex contain renal corpuscles , proximal & distal parts of tubules. Apices of renal pyramids are known as renal papilla. Renal papilla open to the renal pelvis via a branch of a renal pelvis called a calyx. Renal sinus-fatty supporting tissue between medullary pyramids

25. PELVICALYCEAL SYSTEM Whole urinary collecting system within the kidney

26. NEPHRON

27. NEPHRON Renal corpuscle Renal tubules

28. RENAL CORPUSCLE GLOMERULUS BOWMAN’S CAPSULE

30. BOWMAN’S CAPSULE Single layer of flattened cells resting on a basement membrane. GLOMERULUS Globular network of anastomosing capillaries. Glomerular capillaries are invested by visceral layer of Bowman’s capsule. These cells are called Podocytes. They have finger like projections .

31. GLOMERULAR FILTRATION BARRIOR Glomerular endothelium Basement bembrane Podocytes

33. RENAL TUBULES Extend from Bowmen’s capsule to collecting duct. PCT Loop of Henle DCT

35. PROXIMAL CONVOLUTED TUBE Longest , most convoluted tube. Found in renal cortex. Simple cuboidal epithelium. Brush border fills the lumen in a section. Cytoplasm pink stained due to mitochondria. Less cells in a section than DCT

38. Loop of Henle is closely associated with parallel capillary loops-vasa recta, peritubular capillaries

42. DCT SHRTER Less convoluted Found in cortex No brush border Large lumen comparing to PCT Small cells. More cells in a section

44. COLLECTING TUBULES Terminal part of DCT. Several get together & form a Collecting duct

46. COLLECTING DUCT Descend through the cortex in parallel bundles called medullary rays. Lined by columnar epithelium. Pale stained. No brush border Consist of 2 cell types intercalated cells(I cells) principal cells

48. principal cells pale cytoplasm. Short microvillus actively reabsorb Na+ ,K+ ,H2O Intercalated cells dark cytoplasm due to concentrated mitochondria ribosome & vesicles. secrete H+ & reabsorb HCO-3 .maintain acid base homeostasis

51. RENAL VASCULATURE

52. JUXTAGLOMERULAR APPARATUS

53. Juxtaglomerular cells smooth muscle cells of afferent arteriole sensitive to blood pressure in afferent arteriole Release enzyme renin Macula densa modified DCT epithelium sensitive to [Na+] within DCT low [Na+] stimulate release of renin from juxtaglomerular cells

54. Lasis cells extra glomerular mesengial cells release erythropoitin

56. URETER Transitional epithelium (urothelium) Muscular tube inner longitudinal muscle layer outer circular muscle layer Impermeable to urine. Prevent water leaking toward concentrated urine.

59. URINARY BLADDER Transitional epithelium Wall has 3 muscle layers (Detrusor muscles)

61. URETHRA In male 3 parts Prostatic urethra urothelium Membranous urethra stratified squamous epithelium Spongy urethra (penile urethra) stratified epithelium or pseudostratified columnar epithelium

64. Acknowledgments Wheater’s functional histology (fifth edition) www.ELSEVIR.com academic.kellogg.cc.mi.us http://biology.clc.uc.edu/Fankhauser/Labs/Anatomy_&_Physiology

65. Functions of different parts of the nephron Groups 6,7,8

66. The functional unit of the kidneyNEPHRON (Site of urine formation)

67. Parts of the nephron Distal Convoluted tubule Bowman’s capsule Collecting tubules Proximal Convoluted tubule Glomerulus Thick ascending limb of Loop of Henle Collecting duct Thin descending limb of Loop of Henle Thin ascending limb of Loop of Henle Hairpin bend of Loop of Henle To bladder

68. Renal processes Tubular Reabsorption Glomerular Filtration Tubular Secretion Excretion

69. Bowman’s capsule Glomerular Filtration The capsular epithelium(podocytes) surrounding the outer surface of the capillary basement membrane forms a part of the glomerular filtration membrane.

71. Podocytes are also involved in regulation of glomerular filtration rate (GFR).

72. When podocytes contract, they cause closure of filtration slits. Decreases the GFR(by reducing the surface area available for filtration)

76. Tubular Secretion of Organic acids and bases Metabolic products such as Bile salts, Oxalate,Urate and Catecholamines are rapidly removed from the body by the PCT. In addition, the PCT secretes harmful drugs or toxins. Eg: Penicillin, Salicylates

77. Cortex H20 300 mOsm/L 20% of water is reabsorbed H20 Medulla 1200 mOsm/L Loop of Henle-Descending limb

78. Na+, K+, Cl-, Ca+2, HCO3-, Mg+2 Thick Thin Loop of Henle-Ascending limb

79. Ca+2, Mg+2 (Paracellular pathway) Na+ K+ 2Cl- 3Na+ 2K+ Na+ H+ Basolateral membrane Tubular Lumen

80. Early Distal Convoluted Tubule(DCT) Impermeable to water and urea K+ NaCl (5%) Dilutes the tubular fluid

81. Late Distal Tubule Two types of cells Principal cells Secretes K+ and Reabsorbs Na+ Na 3Na 2K K Lumen

83. The H+/ATPase pump can secrete H+ against a very high conc. gradient.CA HCO3- + H+ H2CO3 H2O + CO2 CA=Carbonic Anhydrase

84. Action of Vasopressin(ADH) H2O

87. Reabsorb s Na+ from the lumen & secrete K+ ions.

89. High level of ADH (Ant diuretic hormone-Vasopressin) Increases water reabsorption Concentrates the solutes in urine

90. Summary

91. RENAL BLOOD SUPPLY-ANATOMY- Group 9,10,11

94. RENAL ARTERIES The aorta gives 2 branches at the L2 vertebral level, which supply kidneys. Left renal artery Right renal artery

96. SEGMENTAL BLOOD SUPPLY According to blood supply, each kidney is divided into 5 vascular segments. Each segment is supplied by one segmental artery. Segmental arteries do not anastomose with each other. Obstruction of a segmental artery leads to necrosis of that particular segment.

97. Segmental artery Lobar artery Interlobar artery Arcuate artery Interlobular artery Afferent glomerular arteriole DISTRIBUTION OF INTRARENAL ARTERIES

98. Interlobar arteries Arcuate artery Interlobular arteries BLOOD SUPPLY TO THE NEPHRONS

99. Afferent glomerular artery Glomerular capillary network Efferent glomerular arteriole GLOMERULAR CAPILLARIES Glomerulus is a special capillary network between 2 arterioles.

100. VASA RECTA & PERITUBULAR CAPILLARIES There are two types of nephrones. Cortical nephrones. Juxtamedullary nephrones. In cortical nephrones efferent arteriole gives rise to peritubular capillaries. In juxtamedullary nephrones it gives rise peritubular capillaries and vasa recta.

104. There are 3 types of capillary networks in kidney. Glomerular capillary plexus Peritubular capillary plexus Vasa recta

105. VENOUS DRAINAGE OF NEPHRONS Interlobular veins Arcuate veins Interlobar veins Intrarenal vein Renal vein INFERIOR VENA CAVA Peritubular capillaries drain into inter lobular veins. Ascending vasa recta can be drained into interlobular or arcuate veins.

106. Interlobular veins Arcuate veins Interlobar veins Intrarenal vein Renal vein INFERIOR VENA CAVA VENOUS DRAINAGE OF KIDNEYS

107. RENAL VEINS

108. SUMMARY.

109. Kidneys And Blood Pressure Regulation Groups - 12, 13, & 14

110. How the body regulates the blood pressure ? Two major parameters of Blood Pressure control 1. Total peripheral resistance 2. Cardiac output Arterial Blood Pressure = Cardiac Output X Total Peripheral Resistance

111. Mechanisms of controlling Blood Pressure Rapid Control  Baroreceptor  CNS ischemic mechanism  Chemoreceptors Combine to cause venoconstriction, increasing venous return, increase heart rate and contractility, arteriolar constriction Intermediate Control (during this time nervous mechanisms usually fatigue and become less important) Long-Term Control (Renal-body fluid pressure control mechanism -hours to days)  RAAS interaction with aldosterone – Regulating ECF volume

113. Renin Angiotensin Aldosterone System (RAAS)

114. How RAAS affect blood pressure regulation ? Increase in Blood volume Increase in venous return Increase in cardiac output BP = CO X TPR Increase in blood pressure

115. Vasoconstriction Resistence = 1 (radius)4 Increase Total Peripheral Resistance BP = CO X TPR Increase blood pressure

116. How the Renin is formed ? Juxtaglomerular Apparatus

117. Stimulations for Renin release 1. Low renal blood flow Stimulate intrarenal baroreceptors 2. Increased sympathetic activity 3. Low concentration of Na+ and Cl- in macula densa

118. Formation of Angiotensin 11

119. Action of Angiotensin 11

121. Action of Aldosterone

122. ADH (Vasopressin) and Blood Volume H2O H2O H2O Hypothalamus Ang II receptors SON PVN Maxillary Body Osmo receptors Increased osmolarity Optic chiasma Posterior Pituitary ADH Anterior Pituitary Vagal afferents Atrial volume receptors Volume Retention TPR

123. Action of ADH

124. Arterial Volume receptors and Hypothalamic osmoreceptors Increase pressure due to Decrease osmotic pressure Increase in blood volume Distension of the atrial walls Hypothalamus Stimulation of receptors Decrease ADH secretion Dilatation of renal arterioles Decrease water reabsorption from the kidney More filtration of fluid in the kidneys Bring the Volume and BP back to normal

125. Action of ANP (AtrialNatriuretic Peptide)

126. Structure of ureters and urinary bladder to perform its function Groups-15,16,17

127. Ureters….. A .begin as a continuation of the renal pelvis B .run retroperitoneally C .just medial to tips of transverse processes of lumbar vertebrae towards the urinary bladder D. join the urinary bladder trigone at its posterolateral corners (behind the urinary bladder)

128. Ureters can pass urine from pelvicalyceal system to urinary bladder because it is a hollow tube macroscopicstructure and its function Ureter 25cm long , A Hollow muscular tube Function!!!

129. There is a very narrow and acute angle at the point where the ureters connect with the bladder Function!!! The acute angle between the ureter and bladder prevents back flow of urine to ureters from the bladder.

131. Comprising 3 – 6 layers of cells.

134. Wall of the ureter Consists of; Urothelium Lamina propria Two smooth muscle layers (in upper 2/3 ) -inner longitudinal layer -outer circular layer Lower 1/3 has also a outermost longitudinal layer

135. Muscle layers-wall of the ureter Outer circular layer Inner longitudinal layer Transitional epithelium

139. Urinary bladder Microscopic structure Mainly relates with its epithelium and wall Epithelium-Transitional epithelium Several cell layers (stretchable) Outer round cell layer (umbrella cells)

140. Structure of the wall of the bladder a. mucosa - transitional epithelium b. submucosa c. muscularis (called detrusor muscle) - 3 layers of smooth muscle -inner longitudinal layer -middle circular layer -outer longitudinal layer d. adventitia

141. Smooth muscle layers Microscopic structure of the wall of the urinary bladder

144. Renal failure or kidney failure is a situation in which the kidneys fail to function adequately

147. Other factors which may help differentiate acute and chronic kidney disease include the presence of anemia and the kidney size on ultrasound.

150. Edema, esp. lower extremity

151. Mental changes

152. Heart failure

153. Nausea, vomiting

154. Pruritus

155. Anemia

156. Tachypenia

158. Toxic overload of the kidneys.

159. Accidents, injuries or complications from surgery (where the kidneys are deprived of normal blood flow for an extended period of time.) e.g.- heart-bypass surgery.

162. Weakness

163. Fatigue

164. Neuropathy

165. Anorexia

166. Nausea

167. Vomiting

168. Seizure

169. Constipation

170. Peptic ulceration

171. Diverticulosis

172. Anemia

173. Pruritus

174. Jaundice

176. Hypertension

177. Polycystic kidney disease

178. Overuse of some common drugs, such as aspirin, ibuprofen, cocaine and acetaminophen

179. Glomerulonephritis

180. HIV nephropathy

181. Reflux nephropathy in children

183. Polycystic kidney disease

184. INVESTIGATION Chronic kidney failure is measured in five stages, which are calculated using a patient’s GFR, or glomerular filtration rate

189. Peritoneal dialysis uses the peritoneal membrane, the lining of the abdomen, to remove excess water, wastes, and chemicals from the body.10 A dialysate passes through the abdomen via a surgically placed catheter. Fluid, wastes, and chemicals pass from capillaries in the peritoneal membrane into the dialysate. After several hours, the waste-carrying dialysate is drained from the abdomen.

190. Kidney transplant

191. REFERENCE Davidson’s Clinical Medicine – 20th Edition (pg.491 – 496) http://www.wikipedia.com http://www.kidney.org http://www.umm.edu/ency/article/000471.htm http://www.fpnotebook.com/REN38.htm http://www.paems.org/eWebquiz/renal%20failure/Dialysis%20CEU.pdf http://www.loyolaems.com/sop/4med.htm#med8 http://www.chpnet.org/BIEM_Res/lectures.asp http://www.emedicine.com/emerg/topic501.htm http://http://www.medonline.com.br/med_ed/med1/iranejm.htm www.auburn.edu/~deruija/renal_part3/sld001.htm