Urinary System. School of Medicine, Zhejiang University 2017/5/25

Transcription

1 Urinary System School of Medicine, Zhejiang University 2017/5/25

2 Components ---kidney : produce urine ---ureters, bladder, urethra: conduct, store and remove the urine ---functions: remove waste products of metabolism regulate the homeostasis secrete some bioactive factors: ---renin ( 肾素 ) ---erythropoietin( 促红细胞生成素 ) ---prostaglandin ( 前列腺素 )

3 1. Kidney ---bean-shaped, 10-12cm in length, 5-6cm in width, 3-4cm in thickness ---hilum: BV, LV, N and ureters enter or out *renal pelvis ( 肾盂 ) : funnel-shaped expension of upper end of ureter *renal calices ( 肾盏 ) : branches of renal pelvis minor calices major calices

4 1) General structure: ---capsule: DCT ---cortex: dark stained medullary ray cortical labyrinth renal columns ---medulla: slight stained renal pyramid(10-18) renal papillae: *renal lobe: one renal pyramid and its bounding cortical tissue *renal lobule: renal tissue including one medullary ray and cortical tissue surround it medulla Cortical labyrinth Medullary rays

5 --- parenchyma( 实质 ) nephron=renal corpuscle + renal tubule ( 肾单位 = 肾小体 + 肾小管 ) renal corpuscle =glomerulus + renal capsule(beginning part of renal tubule) ( 肾小体 = 血管球 + 肾小囊 ) uriniferous tubules=renal tubule+ collecting tubule( 泌尿小管 = 肾小管 + 集合管 ) ---interstitium: CT, BV, N

6 Renal corpuscle Glomerular capsule Glomerulus Proximal tubule Renal tubule Distal tubule uriniferous tubules Thin loop Collecting tubules

7 2) Nephron: structural and functional unit 1 renal corpuscle: cortical and juxtamedullary nephron renal glomerulus: renal capsule

8 1renal corpuscle: spherical, 200um in D, two poles: vascular pole and urinary pole ---glomerulus: afferent arterioles capillary network efferent arterioles *capillary network: (fenestrated capillary) /endothelial cell: pore, nm, no diaphragm /basal lamina: 330nm(pore with 4-6 nm)

9 *intraglomerular mesangium( 球内系膜 ) /mesangial cell: ( 球内系膜细胞 ) ---small, irregular, with processes ---small dark N ---EM: RER, Golgi, lysosome, phagocytic vesicles, cytoskeleton-mf, MT,IF and secretory granules /functions: i. produce ground substance ii. phagocytosis iii. contract iv. secrete renin and enzymes /matrix: -type IV collagen -glycoprotein: sulphate chondritin, heparin and dermatan

10 ---renal capsule: two layers capsule formed by beginning part of renal tubule which is enlarged and invaginated /parietal layer: simple squamous epi. /visceral layer: podocytes /renel capsular cavity: the space between two layers

11 *podocyte: ( 足细胞 ) cells with many processes ( primary and secondary processes-foot processes) Foot processes: interdigitated with each other and embraced the capillaries, slit pore: -narrow intercellular space between foot processes -25 nm, with 4-6 nm diaphragm-slit membrane ---function: produce filtrate by filtration

12 *filtration barrier or membrane: ( 滤过屏障 / 滤过膜 ) the structure for filtration is called filtration barrier or membrane, including: fenestrated endothelial cell: negative ions basal lamina: type IV collagen, proteoglycan, lamininnegative ions (sulphate heparin) slit membrane ---nephrin(size selective filter: negative ions ---function:produce crude urine (180L/day)

13 (2) renal tubule: a.proximal tubule:( 近端小管 ) 50-60µm in D, 14 mm long ---structure LM: EM: Pyramidal/cuboidal eosinophilic round N brush-liked border microvilli(apical canaliculi and vesicle) longitudinal striation plasma membrane infold (rich in Na+ K+ ATPase) no clear boundary lateral extension ---Function: i. Re-absorption : -85% ions and water -All of glucose, amino acid, polypeptide, proteins and vitamin -50% bicarbonate salt and sulphate salt ii. secrete H +, NH 3, hippuric acid and creatinine ( 肌酐 )

14 LM/EM: microvilli

15 b. thin segment: ( 细段 ) /10-15 um, simple squamous epi, /facilitate the passage of water and ions /reabsorb Na + and Cl - and 5% water

16 c. distal tubule: ( 远端小管 ) ---structure: LM cuboidal slight-stained round N no brush-liked border less microvilli well-developed longitudinal striation ----plasma membrane infolding ---function: i. reabsorption of 8% water, Na + ions ii. excretion of K +, H +,NH 3 iii. regulated by aldosterone(adrenal gland) and antidiuretic hormone (vasopressin) (pituitary gland) EM

17 LM/EM:

18 3) collecting tubule: arched collecting tubules cortical collection tubules medullary collection tubules ---simple cuboidal epi. to simple columnar epi. ---slight stained ---have clear boundary ---reabsorb 4% water

19 泌尿小管各段上皮细胞结构模式图

20 4) juxtaglomerular(jg) apparatus ( 球旁复合体 ) 1 Juxtaglomerular cells 2 Macula densa 3 Extraglomerular mesangial cells 4 Peripolar cells

21 1. juxtaglomerular cell: ( 球旁细胞 ) ---a groups of modified SM cell of afferent arterioles ---structure: -larger, cuboidal in shaped, with round N -contain secretory granules

22 ---function: secrete renin 肾素 renin angiotensinogen angiotensin I angiotensin II contraction of SM of BV blood pressure adrenal gland aldosterone DT and CT reabsorb Na + and H 2 O Blood volume blood pressure

23 2. macula densa 致密斑 ---a group of cells derived from epi. of distal tubule ---cell becomes taller, narrow, with round N apical part arranged ---cells have processes connecting with other cells ---function: chemoreceptors- feel the Na + ions concentration

24 3. extraglomerular mesangial cell ( 球外系膜细胞 ) (polar cushion cell) ---similar to intraglomerular mesangial cell ---transfer the information 4. peripolar cell ( 极周细胞 ) ---structure: EM: -microvilli -junctional complexes -RER, Golgi, and granules ---function: regulate the reabsorption and secretion of renal tubule

25 5) renal interstitial: CT ---fibers: type I,III,IV collagen ---matrix ---cell: fibroblast, macrophage lipid-laden interstitial cell: -stellate cell with processes -osmiophilic lipid droplets: -function: i. involve in formation of F and matrix ii. secret prostaglandin Endothelium cell: i. secrete erythropoietin to promote erythropoiesis

26 6). Blood supply to the kidney Capsule capillary network Stellate veins Afferent arterioles Glomerulus Efferent arterioles capillary network Interlobular arteries Interlobular veins Arcuate arteries Arcuate veins Interlobar arteries Interlobar veins Renal artery Renal veins

27 6) Features Blood flow in the kidney i. Very large blood flow (1.2L/min) ii. To form capillary two times iii. Glomerular cap. have a high blood pressure iv. Form vasa recta loop near medullary loop v. More larger blood flow in renal cortex

28 2.Excretory Passages 1. Ureter 2. Bladder 3. Urethra Mucosa Muscularis Adventitia

29 Ureter:

30 Bladder: 1.mucosa 2. muscularis 3. fibrosa

31 Clinical Considerations A. Glomerulonephritis It is a type of nephritis characterized by inflammation of the glomeruli. It often occurs secondary to a streptococcal infection elsewhere in the body, which is thought to result in deposition of immune complexes in the glomerular basal lamina, damaging it and markedly reducing its filtering ability. B. Acute tubular necrosis C. Chronic renal failure

32 KEY POINTS General structure of the kidney. Composition of the nephron. Structure and function of the renal corpuscle. Filtration membrane Structure and function of the renal tubule and the collecting tubule. Composition, structural features and functions of the juxtaglomerular complex.