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79 Cards in this Set
- Front
- Back
what are the three general functions of the kidney
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1. excretory 2. homeostatic 3. endocrine
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Describe the macroscopic structure of the kidney
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Solid organ mostly parenchyma, little stroma. Cortex= granular, hoomgenous w/ medullary rays, Medulla=striated, 6-18 renal pyramids
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What is included in a dney lobe
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macroscopic subdivision= renal pyramid+ surronding cortex
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What is included in a kidney lobule
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microscopic=medullary ray+cortical tissue (nephrons)
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Describe the blood supply to the kidney (CO, filtration volume)
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20-25% OF CO, 125 ML of fluid extracted from blood/min, 124ml reabs.
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Describe the aterial supply to the kidney
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renal=>lobar=>interlobar=>arcuate=>interlobular=> afferent arteriole/ subscapular a.
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Deseribe the flow of blood around the nephron
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into the glomerulus via the afferent arteriole, exit via the efferent arteriole to the peritubular capillarys (vasa recta for juxtamedullary nephrons)
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How do cortical and juxtamedullary nephrons differ
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juxtamedulary have longer think segments of LOH, vasa recta maintain osmotic gradients in interstitium of medulla
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what properties of the vasa recta facilitate the maintenece of interstitial osmotic gradient
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countercurrent multiplier, descending loops is lined with continuous epithelium, ascending loop is fenestrated
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how does the structure of the afferent and efferent arterioles contribute to glomerular filtration
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the afferent is larger in diameter than the efferent, the size difference creates a pressure differences that drives filtration
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Describe the structure of the epithelium of Bowman's capsule
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double layered parietal and visceral. Parietal is simple squamous, reflects onto golmerular capillaries to become visceral which is also simple epithelium. Visceral is composed of podocytes which have pedicles. Space between the two layers=urinary space, continous with PT
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What are the three components of the glomerular filtration barrier
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1. Glomerular capilllary endothelium 2. Glomerular basement membrane 3. Visceral Layer of Bowman's capsule (podocytes)
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Describe the structure of the glomerular capilllary endothelium
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discontinuous, freely permeable to water and solutes, luminal surface has negative charge b/c coated with glycocalyx w/ negativley charged proteoglycan molecules
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Describe the structure of the glomerular basement membrane
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2-3 x thicker than normal BM, physical and charge barrier to proteins, three layers 1. lucent (lamina rara interna) rich in polyanions 2. basal lamina (type IV collagen) 3 lucent (lamina rara externa), rich in polyanions
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Which part of the glomerular filtration barrier is the primary barrier that prevents protein from entering the glomerular filtrate
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glomerular basement membrane
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Describe the structure of the visceral layer of bowman's capusle, the third layer of the glomerular filtration barrier
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podocytes w/ pedicles that interdigitate along GBM, spaces between pedicles= filtration slit,
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describe the structure of the filtration slits foubetween pedicles of podocytes
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bridged by electron dense filtration slit diaphgragm, modified adherens junction w/ nephrin, coverd with podocalyxin
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Describe the structure of the renal mesangium
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cells and ECM that abut the inner surface of the GBM, modified pericyte/ smooth muscles cells that have receptors for ANP and AGII, secerte enodthelin, cytokines, prostaglandins
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What are the three functions of the renal mesangium
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1. physical support of glomerus 2. regulation of glomerular blood flow 3. regulation of turnover of GBM
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Describe glomerulonephritis
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injury to glomerulus via inflammation, mediated by immune complexes, compromised filtration= proteinuria, hematuria, oliguria, edema, hypertension, rapidly progressing forms can be fatal
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What type of epithelium lines the convoluted portion of the proxmial tuble
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cuboidal to columnar, brush border at apex caoted with glycocalyx
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Describe the unqiue features of the proximal tubule convoluted protion that faciltate reabs.
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1. brush border on apex 2. infoldings of apical cell mebrane 3. lysoscomes and apical vesicles 4 numerous mitocondria at base
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What type of epithelium lines the straight portion of the proximal tubule (thick descending limb)
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cuboidal
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What is the relative concentration of the fluid leaving the proximal tubule
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isosmotic, sodium and water reabs. isosotically
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How do cortical and jutxamedullary nephrons differ in terms of length of the LOH
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cotrical nephron have short loops and only a descending thin limb, juxtamedulr have asceing and descending thin limbs and are much longer
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How does the type of epithelium difer between the thick and thin segements of the LOH
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thick=cuboidal , thin= simple squamous, note also that in the thin ascending limb the cell membranes are interdigitated making them impereable to water
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what type of epithelium lines the straight portion (thick ascending limb) of the distal tubule
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simple cuboidal
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What are the special features of the cells lining the straight portion (thick ascending limb) of the distal tubule
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simple cuboidal, apical surface has few microvilli and efficient tight junctions at the lateral border, extensive interdigitations of lateral and basal cell membranes, abundant mitochondria
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What type of epithelium lines the convolut portion of the distal tubule
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simple cuboidal
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What are the unique features of the cells that line the convoluted portion of the distal tubule
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few microvilli, fewer mitochondria and basal interdigitations than straight portion
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What type of epithelial cellls line the collecting duct
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cuboidal to columnar, brush border at apex caoted with glycocalyx
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Describe the structure and function of principle cells
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found in collecting duct, have one primary cilium (acts as flow sensor) and ADH sensitive AQP-2 cahnnels
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Describe the structure and purpose of the primary cilium of the priniciple cells of the collecting duct
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Acts as flow sensor, function mediated by polycystin 1 and 2, defects in these proteins relt in polycystic kindey disease
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Describe the structure and function of intercalated cells of the collecting duct epithelium
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apical fold, microvilli, apical vesicles, basal membrane infoldings, numerous mitochondria, function to maintain acid-base balance
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What are some of the results of tubular disease
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affects reabs and secretory fxns, can result in polyuria or oligo/anuria, renal failure, acidosis
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How does the countercurrent multiplier effect produced a hypotonic fluid in the distal tubule
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The asecnding limb of the LOH is impermeable to water while the descending limb is somewhat permeable. The solutes that are pumped out of the ascending limb "draw out" water from the descending limb
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How does structure of the vasa recta maintain the ionic gradient established by the countercurent multiplier system of the tubules
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countercurrent exhange. The arterioels around the decending limb (which is permeable to water) have a continuous epitheilum whereas those around the ascending limb (which is impermable to water) have fenestrated epithelium. This ensures that water is quickly pulled out of the interstitum when it is diffusing out of the decensding loops but the solutes being pumped out of the ascending limb are not removed. This mantains the osmotic gradient
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What are the three components of the juxtaglomerular apparatus
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1. renin producing JG cells 2. Extraglomerular mesangial cells 3. macula densa
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Describe the structure and function of renin producing JG cells of the juxtaglomerular apparatus
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Modified smooth muscles cells in the walls of the afferent arteriole, secrete REnin leading to the production of AG II, results in vasocostriction and incase in aldoesterone secretion leading to increase Na and H2O reabs==>increase BP and blood volume
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What is the function of the extraglomerular mesangial (lacis) cells
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connected to JG and extraglomerular mesangial cells by gap junctions ,may be invovoled in erythorpoietin production
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Where is the macula densa located? What does it do
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part othe JGA, consists of columnar cells of the distal convoluted tubule adjacent to the afferent arteriole, detect Na and Cl concentation and pass information to JG cells to contorl renin secretion so as to control filtration rate and autoregulate blood volume
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which cells secrete erythropoietin? What does it do
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secreted by intersitital cells of renal cortex, simulates divison of RBC precursors, increases release of RBCs from bone marrow. stimulated by hypoxia
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Acute kidney injury can result from prerenal (vascular), intrinsic (kidney tissue) or post renal (obstructive) injury. What are some consequences of acute renal failure
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GRF decreases, azotemia, oligouria, ischemia, incrase of toxins in blood
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ESRD is irreversible and can be caused by gomerular inury, autosomal donmina polycystic kidney disease and other issues. what are some consequences of ESRD
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uremia, hematuria
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What type of epithelium makes up the mucosal lining of the calyces, pelivs, and ureters
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transitional
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the transitional epithelial cells that line the excretory passages of the renal system contain plaques in their apical membranes. What is the function of these plaques
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plaques are associated with actin filaments in the cell cortex. in the relaxed state, the plaques form infoldings (fusiform vesicles) whose lumen is continous with the tubule lumen. In the distended state, the plaques can unfold allowing the apical membrane to expand.
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Describe the muscularis layer of the excretory passages
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between mucosa and adventitia, consists of thin layers of smooth muscle, in upper 2/3 of ureter there are two layers (inner=longitudinal, outer= circular) in the lower 1/3 there are three layers (inner=longitudinal, middle= circular, outer= longitudinal)
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what are the three layers of coverings around the excretory passages
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from inside to out mucosa, muscularis, adventitia
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Describe the layers that cover the bladder
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inner mucosa is transitional epithelium, next is 3 layers of smooth muslce, the superior surface is then covered with peritoneum forming a serosa while the exterior layer of the sides and base is an adventita
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Describe the musculature of the bladder
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The mscularis (detrusor muslce) has three layers, at the neck of the bladder the smooth muscle forms the interna lsphincter.
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How is the bladder innervagted
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sympathetic for vascular control, parasympathetic for micturition control
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How does the epithelial lining of the male urethra change from proximal to distal
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prostatic portion=transitional epithelium, membranous and penile are stratified to pseudostratified columnar epithelium, navicular fossa at distal tip is lined with nonkeratinized stratified squamous
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Describe the differences between the male and female urethra
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male is longer (15-20cm) and has multiple functions, female is shorter (3-5cm) urinary function only
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Describe BPH
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affects males >45, hypertorphy of the glands of the prostate surronding the urethra,can cause urethral obstruction
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Describe renal calculi, causes
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common in sedentary men, hereditary, hypercalcemia, pH change, supersaturation of ions
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What are the components of a renal corpuscle
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glomerulus, mesangial cells, bowman's capsule
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what type of capillaries are found in a glomerulus
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fenestrated
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what type of epithelium makes up the parietal layer of Bowman's capsule
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simple squamous
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What are teh three types of cells within the glomerulus
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capillary endothelial, podocytes, mesangial cells
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What is the space between the glomerulus and the parietal layer of bowman's capsule
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urinary space
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What components make up the fitration barrier
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1. capillary endothelium (fenestrated) 2. glomerular basement membrane 3. podocytes (visceral layer of Bowman's capsulsle, simple epithelium)
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Plasma ultrafiltrate drains from the urinary space into...
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proximal tublue
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Discribe the difference in epithelium type between the PT, DT, and CD
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PT=high cuboidal, DT=low cuboidal, CD= cuboidal=>columnar
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Discribe the difference in lumen characteristics between the PT, DT, and CD
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PT=occluded, DT=open, wide, smooth contour, CD=open, "scalloped" edge b/c cells buldge inwards
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Discribe the difference in cell borders between the PT, DT, and CD
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PT=indistinct, DT=indistinch, CD= distinct
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Discribe the difference iin nuclei in a given plan of section between the PT, DT, and CD
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PT=few, basal, DT=many, central CD=many central
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Describe the differences in cytoplasmic staining between the PT, DT, and CD
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PT=eosinophilic, granular, DT and CD= pale
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why will PTs outnumber DTs in a given corss section
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DTs are shorter than PTs
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WHy does the lumen of the PT appear occulded
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brush border extends into the lumen
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why are the cell borders of the PT and DT indistinct
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extensive interdigitations of lateral plasma membranes
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how does the epithelium change as you move from PT to thin descending limb
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cuboidal to simple squamous
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How can you distinguish a CD from PTs and DTs
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CD has larger lumen and distinct borders between cells, cuboidal to columnar cells, scalloped edge because apical surfaces of cells buldge into lumen
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what substance makes up the kidney stroma
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reticular fibers
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what are the three tunics around the ureter
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mucosa (transitional epithelium), muscularis, adventitia
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How can the number of layers of muscular help you figure out where in the ureter a sample came from
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upper 2/3 has two layers longitudina and cicular, lower 1/3 has three longitudinal, circular, longitudinal
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what protein makes up the fibers in the lamina propria of the bladder
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elastin
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How many layers of smooth muscle does thate bladder have
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3
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the majority of blader cancers arise from what cell type
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urothelial
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how does the shape of a transitional epithelium change when the organ is relaxed or tense
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when relaxed, the cells are "cobblestoned" when stretched, they lay flat
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