5 – Development of Urinary System II

Question 1

What is in the outer stripe of the outer medulla?

Answer 1

-proximal straight tubule
-thin tubules of Loop of Henle
-distal straight tubules
-collecting ducts
-vasa recta
*5

Question 2

What is in the inner stripe of the outer medulla?

Answer 2

-thin tubules of Loop of Henle
-distal straight tubules
-collecting ducts
-vasa rect
*4

Question 3

What is in the inner medulla zone?

Answer 3

-collecting ducts
-thin tubules of Loop of Henle (bottom of them as they make the turn)
-vasa recta
*3

Question 4

Capsule surrounding the kidney:

Answer 4

-kidneys are retroperitoneal=capsule NOT serosa

Question 5

What is the cortex?

Answer 5

-renal corpuscles
-medullary ray
-collecting duct
-distal AND proximal convoluted tubules
-maculla densa (distal straight tubule)

Question 6

Medullary rays:

Answer 6

-refers to the destination
-collecting ducts (and thin tubules)=not as thick=looks clearer

Question 7

Urinary pole of a glomerulus:

Answer 7

-where the filtrate is entering the proximal convoluted tubules

Question 8

Convoluted vs. straight proximal or distal tubules:

Answer 8

-convoluted=when around a glomerulus

Question 9

Macula densa:

Answer 9

-where the straight distal tubule comes back near the glomerulus

Question 10

Parietal layer of bowman’s capsule:

Answer 10

-simple squamous
-merges with proximal convoluted tubule epithelium

Question 11

Vascular pole of glomerulus:

Answer 11

-parietal and visceral layers coming together

Question 12

Vasa recta:

Answer 12

-capillaries from the EFFERENT arterioles
-provide nutrients and oxygen to the nephrons

Question 13

Cloaca:

Answer 13

-caudal end of hindgut that is an endodermally lined chamber
-closed by CLOACAL or ANAL MEMBRANE

Question 14

Urorectal septum:

Answer 14

-mesodermal tissue
-found between hindgut and base of allantois
-as development continues it GROWS TOWARDS CLOACAL MEMBRANE DIVDING CLOACA INTO RECTUM AND UROGENTIAL SINUS (cloaca partitioning)
>cloacal membrane is split into ANAL and UROGENITAL membranes
-perineal body is formed

Question 15

Bladder develops from:

Answer 15

-pelvic region of urogenital sinus (following cloacal portioning)
*from original gut tube=endodermally lined

Question 16

The more caudal part of the urogenital sinus will form the:

Answer 16

-urethra
>endodermally lined (b/c it’s from original gut tube)

Question 17

The urogenital sinus is continuous with:

Answer 17

-the allantois
>distal end relative to bladder will form URACHUS

Question 18

As the MALE bladder grows it incorporates the:

Answer 18

-terminal parts of the mesonephric and ureteric ducts
>each duct system develops its OWN SEPARATE OPENINGS into the developing bladder

Question 19

After separation, the mesonephric ducts are initially anterior (cranial) to ureteric buds, but gradual positions shift so:

Answer 19

*ureteric buds finally open into bladder laterally and anterior (cranial) to mesonephric ducts

Question 20

Trigone:

Answer 20

-triangular area in the dorsal wall of the bladder
-marks the region of the mesonephric duct and ureteric bud incorporation
>bladder: endoderm
>mesonephric duct: mesoderm

Question 21

Female bladder:

Answer 21

-don’t need mesonephric duct for reproduction (degenerates over time)
>trigone is small
> ureters still attached to bladder
-use mullerian duct (para-mesonephric duct)

Question 22

Development abnormalities of the kidneys examples:

Answer 22

-renal agenesis
-renal hypoplasia
-migration defects (ectopic, crossed-ectopic)
-horseshoe kidney
-polycystic kidney

Question 23

Renal agenesis:

Answer 23

-complete absence of one (unilateral) or both (bilateral) kidneys
-can be associated with absence of ureter
-animal can appear normal if it’s unilateral (may be bigger from hyperplasia)

Question 24

Unilateral renal agenesis is most common congenital kidney condition in:

Answer 24

-pigs
-can be a familial disposition in dogs (ex. Beagles)

Question 25

Renal agenesis is a result of the:

Answer 25

-failure of the development of one or both ureteric buds
>there is NO induction of the metanephric mass to form renal tubules

Question 26

Renal hypoplasia:

Answer 26

-substantially small kidneys due to immature glomeruli and tubules
-unilateral and bilateral (bilateral=lethal in fetal period=we don’t see it)
-most common in many breed dogs
-treatment is associated with managing associated chronic renal failure

Question 27

What is the most common migration defect?

Answer 27

-ectopic kidney: kidney left in the PELVIC cavity

Question 28

What is another form of a migration defect?

Answer 28

-crossed ectopia: 1 kidney and its associated ureter on the same side as the other kidney

Question 29

Migration defects ‘signs’:

Answer 29

-largely asymptomatic
>can be associated with increased infections

Question 30

Horseshoe kidney:

Answer 30

-kidneys become fused at inferior poles
-origin is uncertain
-seen in all species
-asymptomatic but may have pain or obstruction of ureters

Question 31

Polycystic kidney: (congenital cystic)

Answer 31

-multiple cysts form in the kidney
>organs are grossly enlarged (happening in many of the nephrons)
-familial in beagles, bull terriers and west highland white terriers
-most common in Persian cats and LH cats (autosomal dominant trait)
-hereditary in pigs
*diagnosis via radiography or ultrasound

Question 32

Polycystic kidney is a result of the:

Answer 32

*failure of developing nephrons to connect with their collecting ducts
-cysts arise from accumulation of urine within nephrons that are isolated form collecting ducts (crystal formation and urea=hard cysts)

Question 33

Polycystic kidney degree:

Answer 33

-depends on how many of the nephrons are effected
-if enough are normal=kidney can function
*treat as chronic renal failure

Question 34

Ectopic ureter is a result of:

Answer 34

-improper development of metanephric duct systems
>ureter ‘drains’ into urethra vs. bladder
-unilateral (L+R equally likely)
-bilateral: 25%

Question 35

Ectopic ureters reported in:

Answer 35

-carnivores
-more common in females
*most common anomaly of the urinary tract in horses
*DRIPPING OF URINE

Question 36

Urachal remnants:

Answer 36

*congenital anomaly resulting from incomplete urachal closure (patent urachus)
-frequent in cats, dogs, and horses

Question 37

Patent urachus is associated with:

Answer 37

-urinary incontinence
-urine scalding of ventral abdomen
-frequent bacterial urinary tract infections