chapter 17 urinary system
DESCRIPTION
Chapter 17 Urinary System. Components --- kidney : produce urine --- ureters --- bladder -cavity organs, conduct, store and --- urethra remove the urine ---functions: remove waste products of metabolism regulate the homeostasis - PowerPoint PPT PresentationTRANSCRIPT
Chapter 17 Urinary System
1. Components
---kidney : produce urine
---ureters
---bladder -cavity organs, conduct, store and
---urethra remove the urine
---functions:
remove waste products of metabolism
regulate the homeostasis
secrete some bioactive factors- renin, erythropoietin
*cavity organs:
mucosa:
/epi-transitional epi
/lamina propria
muscularis: SM
adventitia: CT
2. 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: funnel-shaped expension of upper end of ureter
*calyx: branches of renal pelvis
1) General structure: ---capsule: DCT---cortex: dark stained /medullary ray /cortical labyrinth---medulla: slight stained /renal pyramid /renal columns /renal papillae: -minor calyx -major calyx -pelvis
*renal lobe: one renal pyramid and its bounding cortical tissue
*renal lobule: renal tissue including one medullary ray and cortical tissue surround it
According to function, renal parenchyma is mainly consists of uriniferous tubules
---parenchyma: /uriniferous tubules= ren
al tubule+ collecting tubules
/renal corpuscle =glomerulus + renal capsule(beginning part of renal tubule)
/nephron=renal corpuscle + renal tubule
---interstitium: CT, BV, N
2) Nephron: structural and functional unit, 1,000,000
---renal corpuscle: cortical and juxtamedullary nephron
/renal glomerulus: /renal capsule---renal tubule: /proximal tubule: -convoluted portion -straight portion /thin segment /distal tubule: -straight portion -convoluted portion
① renal corpuscle: spherical, 200um in D, two poles: vascular pole and urinary pole
---glomerulus: afferent arterioles→capillary network →efferent arterioles
*capillary network:
/endothelial cell: pore, 70-90 nm, no diaphragm
/basal lamina: 330nm
*intraglomerular mesangium: /mesangial cell: -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
---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 layer
s
cells with many processes ( primary and secondary processes-foot proce
sses)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
*podocyte:
---function: produce filtrate by filtration
* filtration barrier or membrane: the structure for filtration is called filtration barrier or membrane, including:
fenestrated endothelial cell: negative ions
basal lamina: type IV collagen, proteoglycan, laminin-negative ions (sulphate heparin)
slit membrane-nephrin(size selective filter: negative ions
② renal tubule:a. proximal tubule: 50-60um in D, 14 mm long---structure LM: EM:
pyramidal cuboidaleosinophilicround Nbrush-liked border - microvilli(apical canaliculi)longitudinal striation- plasma membrane infoldingno clear boundary - lateral extension
(rich in Na+ K+ ATPase)
Proximal tubule
---Function:
i. reabsorption :
-85% Na+ ions and water
-All of glucose, aminoacid, polypeptide, proteins and vitamin
-50% bicorbonated salt and sulphate salt
ii. secrete H+, NH3, hippuric acid and creatinine
b. thin segment:
/10-15 um, simple squamous epi,
/facilitate the passage of water and ions
/reabsorb Na+ and Cl- and 5% water
c. distal tubule:
---structure:
LM: EM:
cuboidal
slight-stained
round N
no brush-liked border – less microvilli
well-developed
longitudinal striation – plasma membrane infolding
Distal tubule Plasma membrane infolding
---function:
i. reabsorption of 8% water, Na+ ions
ii. excretion of K+, H+,NH3
iii. regulated by aldosterone(adrenal gland) and antidiuretic hormone (vasopressin) (pituitary gland)
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
4) juxtaglomerular complex
极周细胞
a. juxtaglomerular cell:
---a groups of modified SM cell of afferent arterioles
---structure:
-larger, cuboidal in shaped, with round N
-contain secretory granules
---function:
i.secrete renin→adrenal gland→aldosterone→blood pressure↑
↑
angiotensinogen→angiotensin I→angiotensin II→contraction of
SM of BV
ii. secrete erythropoietin to promote erythropoiesis
b. macula densa---a group of cells derived from epi. of distal tub
ule---cell becomes taller, narrow, with round N apic
al part arranged---cells have processes connecting with other c
ells---function: chemoreceptors- feel the Na+ ions c
oncentration
c. extraglomerular mesangial cell(polar cushion cell)
---similar to intraglomerular mesangial cell---transfer the informationd. peripolar cell---structure: EM: -microvilli -junctional complexes -RER, Golgi, and granules---function: regulate the reabsorption and secret
ion of renal tubule
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
6) Blood supply to the kidney
i. Very large blood flow (1.2L/min)
ii. To form cap.two timesiii. Glomerular cap. have
a high blood pressure
iv. Form vasa recta loop near medullary loop
v. More larger blood flow in renal cortex
Interlobar arteries → Arcuate arteries →Interlobular arteries →Capsular cap. ↑ ↓ ↓Renal artery Afferent arterioles Afferent arterioles ↓ ↓ Juxtamedullary nephron Cortical nephron glomerulus glomerulus ↓ ↓ Efferent arterioles Efferent arterioles ↓ ↓ Vasa recta(artery and vein)← Capillary network Capillary network ↓ ↓ ↓ Renal vein←Interlobar vein← Arcuate vein ← Interlobular vein ← Stellate vein