Urinary System

Question 1

Function of urinary system

Answer 1

clear blood of waste products, regulate concentration of fluids, regulate blood pressure, produce EPO (stimulates RBC production), produce renin (influences blood pressure and [Na+])

Question 2

Parts of nephron

Answer 2

Renal corpuscle, proximal convoluted tubule, henle’s loop: thick descending limb (descending pars recta), thick ascending limb, thin limb; distal convoluted tubule; collecting duct

Question 3

Parts of nephron in cortex

Answer 3

proximal & distal convoluted tubules, renal corpuscle, parts of collecitng duct

Question 4

Parts of nephron in cortex

Answer 4

Loop of henle: thin limb, thick ascending limb, thick descending limb?

Question 5

area cribrosa

Answer 5

perforated tip of of renal papila at apex of renal pyramid, papillary ducts through perforations

Question 6

Pars convoluta

Answer 6

part of cortex: renal corpuscle, proximal and distal convoluted tubules.

80% si proximal convoluted tubule

Question 7

columns of bertin

Answer 7

cortical tissue b/w medullary pyramids

Question 8

Pars recta

Answer 8

medullary rays, straight tubules that project into cortex from base of renal pyramid

Question 9

Renal lobe

Answer 9

renal pyramid with closely associated cortical tissue

Question 10

Renal lobule

Answer 10

Medullary ray with closely associated cortical tissues.
All nephrons in lobule drained by a singe collecting duct
one interlobular blood vessel to the next interlobular blood vessel

Question 11

Uriniferous tubule

Answer 11

nephron and collecting tubule. have separate primordia

Question 12

Cortical nephrons

Answer 12

short loops of henle. important for H2O absorption and forming hypertonic urine

Question 13

juxtamedullar nephrons

Answer 13

relatively short loops of henle

Question 14

Cells of proximal convoluted tubule and thick descending limb

Answer 14

large, eosinophilic, brush border, central nucleus

Question 15

Cells of distal tubule (ascending and convoluted)

Answer 15

basal striations, smaller, nucleus more apical

Question 16

Cells of thin limb

Answer 16

squamous, with visible cytoplasm for “lollypop” appearance

Question 17

Cells of collecting duct

Answer 17

appear to have separations of lateral surface (actually interdigitations/fluting caused by H2O absorption)

Question 18

Renal corpusle

Answer 18

Glomerulus (capillary tuft) and Bowman’s capsule
lined by simple squamous epithelium–>lining bowman’s capsule is known as parietal layer or capsular epithelium
epithelium lining capillaries has basal lamina fused to basal lamina of endothelium

Question 19

Bowman’s space

Answer 19

capsular/urinary space–>narrow chalice shaped cavity b/w visceral and parietal epithelial layers

Question 20

Vascular pole

Answer 20

afferent arteriole enters, efferent arteriole leaves

Question 21

Urinary pole

Answer 21

becomes continuous with lumen of proximal convoluted tubule

Question 22

Appearance of proximal convoluted tubule

Answer 22

brush border, lots of debris from broken micorvilli in lumen

Question 23

Podocytes

Answer 23

modified simple squamous epithelium with 1º and 2º processes (pedicles/foot processes)–>basal lamina fuses with basal lamina of endothelial cells at level of lamina densa (3 layers to basal lamina: rara externa, densa, rara interna)

filtration slits (slit pores) 20-30 nm b/w adjacent pedicels, bridged by filimentous slit diaphram (membrane)

Podocalyxin coating of pedicel surface maintains shape and organizaion. Stains with cationic dies (i.e.: - charge–>prevent - charged solutes from getting through)

Question 24

Glomerula endothelium

Answer 24

Fenestrated (60-90 nm fenestrae) with no diaphragm (the podocytes do have a diaphram on the other side of the basement membrane

most organelles in thicker unfenestrated regions of cytoplasm

Question 25

Filtration barrier

Answer 25

filters blood plasma in rena corpuscle

permits: h2o, ions, small molecules
prohibits: proteins greater than 69 kD or high net negative charge, also based on shape

Components: fenestrated endothelium, basal lamina, filtration slits with diaphragms

Question 26

Intraglomerular Mesangium

Answer 26

Interstitial space b/w capillaries of glomerulus

contains mesangial cells and ECM

Mesangial cells are phagocytic and maintain functional integrity of basal lamina in filtration barrier–>phagocytose large proteins molecules and/or debris

contract to decrease surface area available of filtration (receptors for angiotensin II and ANF)

Question 27

Proximal convoluted tubule

Answer 27

leaves renal corpuscle; longest segment of nephron; single layer of pyramidal-shaped cells wish well developed brush border; cells have endocytic complex (apical canaliculi, vesicles, vacuoles) for protein absorption; lateral borders have extensive interdigitations (fluting, h2o transport); eosinophilic; extensive basal plasma membrane infodings w/ mitochondria; regulates blood pH by secreting H+, taking in bicarb, and secreting organic acids and bases;
absorbs 80% of Na+ and H2O, all glucose, amino acids, and small proteins

Question 28

Descending Pars recta

Answer 28

simple cuboidal epithelium prominent brush border; shorter and less elaborate than proximal convoluted tubule but generally the same; damaged in acute renal failure or Hg poisoning; initial part (thick descending) of loop of henle

Question 29

Thin limb of loop of henle

Answer 29

descending limb, loop, ascending limb; simple squamous; nuclei bulge into lumen; only a few short microvilli; 4 distinct segments based on shape, organelles, depth of tight jxns, and H2O permeability; middle part of loop of henle

Question 30

ascending thick limb of distal tubule

Answer 30

simple cuboidal epithelium; only a few microvilli; nuclei are apical; mitochondria compartmentalized in lateral and basal interdigitations/infoldings; transport ions from lumen to interstitum; impermeable to H2O; luminal fluid becomes hypotonic to blood

Question 31

Distal convoluted tubule

Answer 31

Begins at macula dense; microvilli shorter than promimal microvilli; nuclei apical; lateral interdigitations; mitochondria in basal cytoplasmic infoldings; actively transport Na+ from filtrate to interstitium

Question 32

Macula Densa

Answer 32

region of distal tubule near afferent glomerular arteriole; compent of juxtaglomerula apparatus; tall, narrow cells lined up closely: dense spot in light microscopy; monitor fluid in distal tubule and send signal to juxtaglomerular cells (modified smooth muscle in tunica media, secrete Renin) in afferent arteriole via Extraglomerular Mezangial Cells

Question 33

Juxtaglomerular cells/apparatus

Answer 33

modified tunica media cells in afferent and efferent arterioles secrete renin in response to signal from macual densa via extraglomerular mezangial cells (in response to decreased extracellular fluid volume)

Question 34

Extraglomerular mezangial cells

Answer 34

transmit signal from macula densa to Juxtaglomerular cells to secrete renin

Question 35

Renin

Answer 35

Leaves angioteninogen to angiotensin I (further cleaved to angiotensin II in capillaries of lung; angiotensin II leads to release of aldosterone from Z. glomerulosa of adrenal cortex)

Question 36

Aldosterone

Answer 36

stimulates distal tubule cells to retain sodium ions–>H2O follows Na+ leading to increased extraceullar fluid (synthesized in Z. glomerulosa of adrenal cortex, stimulated by angiotensin II)

Question 37

Angiotensin II

Answer 37

potent vasoconstrictor, elevates blood pressure (in addition to stimulating relase of aldosterone or maybe because of it I’m not sure)