Urinary Flashcards
What is the depression in the kidney’s concave surface where vessels, ureter, and nerves pass into or leave the kidney called?
Hilum
What does the hilum open into?
renal sinus
What is the funnel-shaped, expanded, proximal end of the ureter?
renal pelvis
The renal sinus is a fat-filled cavity enclosing the following:
- branches of the renal artery, and vein, lymph vessels
- ureter and nerve fibers
What does the outer layer of the kidney capsule have? inner layer?
outer: collagen and fibroblasts
inner: myofibroblasts
What are the layers of the kidney from inner to outermost?
medulla -> cortex -> capsule
The cortical tissue overlying the base of a pyramid is …
the cortical arch
What are the two alternating regions that make up the cortex?
cortical labyrinth and medullary rays
What 3 structures are found in the cortical labyrinth?
- Renal corpuscles
- Convoluted tubules (PCT and DCT)
- Collecting tubules
What is the medullary tissue that extends from the base of the pyramids into the cortex in longitudinal striations?
Medullary rays
What structures are found within the medullary rays?
- straight tubules ( proximal and distal )
2. collecting ducts
True or False: 90% of the blood flowing through the kidney is in the medulla.
FALSE
cortex not medulla
-the blood will be filtered through the glomeruli
What two structures are found in the medulla?
- renal pyramids
2. renal columns of Bertin
How many renal pyramids are there per kidney?
8-18
Where does the apex of the renal pyramid drain?
minor calyx
What is another name for the apex of the renal pyramid?
renal papilla
What consists of approx. 20 openings of the ducts of Bellini?
Area cribosa
Where is the base of the renal pyramid?
at corticomedullary border
What are the renal columns of Bertin?
cortical tissue projecting between medullary pyramids
they are considered part of the medulla
What two structures are included in the renal columns of Bertin?
- straight tubules of the nephrons
- collecting ducts
What structure receives the apex of one pyramid?
minor calyx
Several minor calyces converge and open/drain into a …
major calyx
What three things compose a kidney lobe?
- renal pyramid
- associated cortical tissue at the base of the pyramid
- associated cortical columns of Bertin (one half of each adjacent renal column)
What composes a kidney lobule?
a collecting duct and all the nephrons that empty into the duct
nephron + collecting tubule = ?
uriniferous tubule
What is the structural and functional unit of the kidney?
nephron
What are the components of a nephron?
- renal corpuscle
- proximal tubule
- thin limbs of henle’s loop
- distal tubule
What are the components of a renal corpuscle?
- glomerulus
- bowman’s capsule
- bowman’s space
- vascular pole
- urinary pole
- filtration barrier
What is the glomerulus?
- a cluster of fenestrated capillaries in an arterio-capillary bed
- glomerular ultrafiltrate oozes out of the glomerulus by passing through the filtration barrier
Where is Bowman’s capsule located?
proximal end of the nephron
What is the visceral layer of Bowman’s capsule composed of and what does it cover?
- composed of podocytes
- covers the glomerulus
What is the parietal layer of Bowman’s capsule composed of?
simple squamous epithelium covered by a basal lamina
What is the space between the visceral and parietal layers of Bowman’s capsule and what does it contain?
Bowman’s space
- contains ultrafiltrate
What is the site where the afferent glomerular arteriole enters the renal corpuscle and the efferent glomerular arteriole leaves?
Vascular Pole
True or False: the diameter of the afferent arteriole is much larger than the diameter of the efferent.
TRUE
What contains the initial part of the proximal convoluted tubule?
urinary pole of the renal corpuscle
Describe the filtration barrier of the renal corpuscle from inside outward.
endothelial surface layer of glomerular capillaries -> fenestrated endothelium of glomerular capillary -> basal lamina -> subpodocyte space -> visceral layer of Bowman’s capsule
What are the two discontinuous layers of the filtration barrier?
- fenestrated endothelium of glomerular capillary
- visceral layer of Bowman’s capsule (podocytes)
What causes congenital nephrotic syndrome?
- mutations in nephrin gene
- leaky slit diaphragm –> massive proteinuria and edema
True or False: The filtrations slits of the secondary processes (pedicles) of the visceral layer of Bowman’s capsule have a diaphragm.
TRUE
True or False: the fenestrated endothelium of glomerular capillary in the filtration barrier has diaphragms over the fenestrations.
FALSE
no diaphragms over fenestrations
What is another name for the proximal straight tubule?
thick descending limb of the loop of henle
Where is the intraglomerular mesangial cell located? what does it do?
- embedded in the basal lamina/basement membrane between glomerular capillaries (vascular pole)
- phagocytic, resorbs basal lamina
What causes Alport’s syndrome (hereditary glomerulonephritis) ?
- mutations in gene encoding for type IV collagen
- causes hematuria, proteinuria, and progressive renal failure
What type of cell populates the proximal convoluted tubule?
simple cuboidal epithelium with microvilli
Describe the histological features of cells in the proximal convoluted tubule.
eosinophilic, granular cytoplasm with PAS + basement membrane
What do you call the entire U-shaped portion of a nephron?
Henle’s loop
Which portion of Henle’s loop makes a hairpin turn?
thin descending loop
The entire thin limb of the loop of Henle is lined with ________________.
simple squamous epithelium
What is another name for the distal straight tubule?
thick ascending limb of the loop of Henle
What type of epithelium is found in the distal straight tubule?
low cuboidal epithelium with few microvilli
- also has zonulae occludens
Which tubule has more mitochondria: distal straight tubule or proximal convoluted tubule?
distal straight tubule
What is the purpose of the macula densa (widened portion of distal tubule between afferent and efferent arterioles)?
This area has chemoreceptors which promote renin secretion by juxtaglomerular cells
Which convoluted tubule is shorter and less torturous?
distal convoluted tubule
Describe the distal convoluted tubule histologically.
- wide, clear lumen
- pale, granular cytoplasm
- smaller cells than PCT
Is the collecting tubule part of the uriniferous tubule? nephron?
YES uriniferous
NO nephron
What does the distal convoluted tubule empty into?
a connecting tubule or arched collecting tubule which will drain into a cortical collecting duct or medullary collecting duct
What are formed as several medullary collecting tubules converge?
papillary collecting ducts of bellini
Where do the papillary collecting ducts of bellini open?
they open into the renal papilla of each pyramid and form the area cribosa ( “strainer” ) of the renal papilla
What type of epithelium lines the papillary collecting ducts of bellini?
tall columnar epithelium
What are juxtaglomerular cells?
modified smooth muscle cells in the tunica media of the AFFERENT glomerular arteriole that contain renin
How does renin increase blood pressure ?
- angiotensinogen is converted by renin into angiotnesin-1
- angiotensin-1 is converted by ACE (lung enzyme) into angiotensin-II
- Angiotensin II constricts arterioles and stimulates secretion of aldosterone by suprarenal cortex
- aldosterone stimulates the macula densa of DCT which increases absorption of sodium and calcium and excretion of potassium
- increased fluid volume in body and blood pressure returns to normal
What drugs are used to lower blood pressure?
angiotensin receptor blockers and ACE inhibitors
Where do extraglomerular mesangial cells reside?
in the interval bordered by the afferent arteriole, macula densa, efferent arteriole, and vascular pole of renal corpuscle
Does the renal interstitium contain connective tissue?
yes, small amount of CT and fibroblasts and macrophages
Describe the blood flow through a kidney.
Renal artery –> anterior and posterior division –> segmental arteries –> lobar arteries –> interlobar arteries –> arcuate arteries –> interlobular arteries –> afferent glomerular arteries
What does the minor calyx receive urine from?
the renal papilla of a single renal pyramid
What does the major calyx receive urine from?
up to four minor calyces
What is the funnel-shaped, upper expanded portion of the ureter called?
renal pelvis
What does the mucosa of the ureter look like when empty?
thrown into folds
What type of epithelium is found in the mucosa of the ureter?
transitional epithelial lining
How is the upper 2/3 of the muscularis of the ureter different from the lower 1/3?
upper 2/3: outer circular layer and inner longitudinal layer
lower 1/3: outer longitudinal layer (extra), middle circular layer, inner longitudinal layer
True or False: the ureters deliver urine to the urinary bladder via gravitational forces.
FALSE
the ureters deliver urine to the bladder via peristaltic waves produced by the muscularis
What type of epithelium is found in the mucosa of the bladder?
transitional epithelium
Is the lamina propria of the mucosa of the bladder more dense superficially or deeper?
dense irregular collagenous CT- superficial
loose layer of CT- deeper
Which layer of smooth muscle forms the internal sphincter of the bladder?
middle layer
What attaches the bladder to surrounding structures?
adventitia
What type of epithelium is found in the female urethra?
transitional near the bladder, but mostly stratified squamous nonkeratinized
Where are glands of Littre located?
- lamina propria of the female and male urethra
- produce mucous
Where is the external urethral sphincter located?
where the urethra penetrates the urogenital diaphragm
- skeletal muscle
What types of epithelium are found in the three divisions of the penile urethra?
- prostatic urethra: transitional epithelium
- membranous urethra: stratified columnar and pseudostratified columnar
- spongy urethra: pseudostratified columnar and stratified squamous nonkeratinized epithelium in the distal end
What glands secrete mucous to lubricate the penile urethral lumen?
Bulbourethral glands of cowper
