RENAL + UROGENITAL DEV'T.

Question 1

The urogenital ridge is derived from the…

Answer 1

Intermediate mesoderm, located along the posterior abdominal wall.

Question 2

The lateral plate mesoderm differentiates into what two types of mesoderm?

Answer 2

The parietal (somatic) which forms the lateral folds of the body cavity and the visceral (splanchnic) which forms the walls of the gut tube.

Question 3

Define the cloaca and it’s significance.

Answer 3

The cloaca is an embryonic membrane where external genitalia forms alongside it (in the perineum)

Question 4

Describe the functions and significance of the kidneys.

Answer 4

Kidneys are located in the lumbar region behind ribs 10-12. They filter 180 liters of blood per day to empty 1-2 liters of urine into the bladder via the ureters. They are primary retroperitoneal organs that play a role in acid-base balance and BP regulation through hormones.

Question 5

List the layers of the kidney from superficial to deep. Include the collecting portion.

Answer 5

Outer cortex > medullary region > papilla > minor calyx > major calyx > renal pelvis > ureter > urinary bladder.

Question 6

Compare and contrast nephrons from collecting tubules.

Answer 6

Nephrons are the functional unit of filtration for the kidney in the medullary region. Collecting tubules transport the urine to empty it into the calyxes and eventually into the ureters.

Question 7

Define the SMA “Nutcracker” Syndrome.

Answer 7

An enlarged SMA or aneurysm of the nearby aorta can compress the left renal vein, 3rd part of duodenum and or the pancreas. This is associated with a dilated left gonadal vein since the backflow is from the left renal vein.

Question 8

Where do kidney stones occur and what kind of pain can be felt with them?

Answer 8

Kidney stones can occur at constriction points such as the ureteropelvic junction, the pelvic brim and the ureterovesicular junction. These can be felt as low loin-to-groin colic pain as the smooth muscle squeezes to move the stone periodically.

Question 9

Describe the path of blood flow for the supply to the kidney.

Answer 9

The renal artery gets off at L1/L2 > multiple segmental arteries > arcuate arteries (@ corticomedullary junctions) > interlobar arteries > afferent arterioles > glomeruli.

Question 10

What are the components of uriniferous tubules?

Answer 10

Nephrons (metanephros) in the renal cortex and collecting tubules (ureteric buds) in the renal medulla are the 2 parts of these tubules.

Question 11

Define the pronephros, where it is located and its purpose in the embryo.

Answer 11

The pronephros is the anterior portion of the nephrogenic ridge @ the cervical region. It is non-function and regresses after week 4.

Question 12

Define the mesonephros, where it is located and its function in the embryo.

Answer 12

The mesonephros is a temporary portion of the nephrogenic ridge located at the thoracic-lumbar region. It was briefly functional but regressed a little after. It is vestigial in females but becomes efferent tubules in males.

Question 13

Define the mesonephric duct and its components.

Answer 13

The mesonephric duct is a specialized part of the mesonephros that gives rise to the ureteric bud. It is composed of the male internal genital system, the trigone (caudal end) that will incorporate into the posterior bladder, and the ureteric bud which forms parts of the collecting system.

Question 14

Define the metanephros, its location and function.

Answer 14

The metanephros is the caudal portion of the nephrogenic ridge that is the PERMANENT filter for the embryo. It is located at the sacral-pelvis region and later forms the renal cortex (filtering system) of the kidney. It is also known as the “definitive kidney”.

Question 15

Describe the process of reciprocal induction in the formation of the kidneys.

Answer 15

Ureteric bud and metanephric caps tell each other what to do as the buds grown into the caps. Ureteric buds cause the metanephric caps to elongate and differentiate into convoluted tubules. Whereas, these buds themselves become future collecting tubules as they elongate too.

Question 16

The right gonadal vein drains into the ______; whereas the left gonadal vein drains into the _______ which drains into the ______.

Answer 16

Right gonadal vein > IVC;

Left gonadal vein > Left renal vein > IVC

Question 17

The embryonic __________ makes up the filtering portion of the kidney which is composed of _______ (the kidney functional unit). The embryonic _______ makes up the collecting portion of the kidney, which make future _______.

Answer 17

Metanephros, Nephrons;

Ureteric bud, Collecting ducts

Question 18

The mesonephric duct becomes what 3 components?

Answer 18

1. Ureteric bud = future collecting tubules of kidney
2. Wolffish duct (male) = internal effluent tubes
3. Trigone = caudal end that becomes the posterior bladder

Question 19

Polyhydramnios involves _____ amniotic fluid in the womb that results from ________ swallowing. In the developing fetus this indicates: _________ or ___________.

Answer 19

A lot of amniotic fluid;
impaired (too little swallowing);
Duodenal atresia or Anencephaly

Question 20

Oligohydramnios features _________ amniotic fluid in the womb from a ______ of urine production. This indicates a lethal congenital defect known as ______.

Answer 20

Too little amniotic fluid;
Lack of urine production;
Bilateral Reynaldo agenesis (not viable)

Question 21

Define Potter’s Sequence.

Answer 21

A syndrome of congenital defects consisting of:

Pulmonary hypoplasia, Oligohydramnios, Twisted face, Twisted skin, Extremity deformities, Renal agenesis (bilateral)

Question 22

Describe what causes an Ectopic kidney.

Answer 22

As the kidneys ascend the inferior poles fuse together leading to a horseshoe shaped kidney that is stuck at the inferior mesenteric artery. The kidneys remain in the pelvis instead of at the L4/5 vertebral levels.

Question 23

As the _________ ducts fold in to become integrated in the posterior bladder wall, this becomes the embryonic _________ and _________.

Answer 23

Mesonephric ducts;

Trigone and Ureteric buds

Question 24

What 2 features of the bladder prevents a backflow of urine into the ureters?

Answer 24

1. Oblique angle of the ureters as they enter the bladder

2. Shunts at the ureterovesical junction

Question 25

The caudal hindgut becomes the cloaca which turns into the _______ sinus which forms the anterior part of the ________.

Answer 25

Urogenital sinus;

Anterior urinary bladder

Question 26

The defective fusion of the lateral body folds at the midline, during development of the urinary bladder would result in…

Answer 26

Bladder Extrophy

Question 27

Name the embryonic derivatives of the following: median umbilical ligament, medial umbilical fold, lateral umbilical folds.

Answer 27

Median ligament from Allontois (embryonic urachus);
Medial ligaments from umbilical veins;
Lateral umbilical folds overly the inferior epigastric arteries

Question 28

Define the function of the following:

Seminiferous tubules, Sertoli cells, Leydig cells

Answer 28

Seminiferous tubules: spermatogenesis occurs here
Sertoli cells: nourish developing spermatocytes
Leydig cells: found within testes CT, make testosterone hormones

Question 29

Describe what a Gartner’s cyst is.

Answer 29

This is a vestigial remnant of the female mesonephric duct located near the fornices of the vagina.

Question 30

In the development of the gonad, the males have their inner medullary regions _________ while the outer cortex _________. In contrast, to form the female ovary, the inner medullary region _________, while the cortical cords __________.

Answer 30

Males: medullary region proliferates, outer cortical region shrinks;
Females: medullary region degenerates, cortical cords proliferate to produce estrogen

Question 31

Describe the significance of testosterone in the determination of internal genitalia (by sex).

Answer 31

A lot of testosterone (for males) leads to mesonephric duct differentiation and regression of the Mullerian Duct system. Little testosterone and Mullerian inhibitor causes an increase in estrogen for production of female ovarian follicles.

Question 32

In males the mesonephric (Wolffian) duct becomes what structures?

Answer 32

Seminal vesicles, ejaculatory duct, epidydimis, ductus deferens “SEEDS”

Question 33

In females, the paramesonephric (Mullerian) duct becomes what anatomical structures? What embryonic structure forms the lower vagina?

Answer 33

Fallopian tubes, upper vagina and uterus. “FUU”

The Urogenital sinus forms the lower vagina.

Question 34

What defect occurs when the paramesonephric ducts fail to fuse at the midline when forming the femal internal genitalia?

Answer 34

Uterus bicornis = defect in paramesonephric ducts leading to 2 horns of the uterus

Question 35

What defect occurs in males from the incomplete fusion of the urethral folds on the ventral aspect?

Answer 35

Hypospadias is marked by an unfused urethral walls in the male, resulting in a leaky penis

Question 36

Describe what occurs during embryological development to the arterial supply of the testicles and kidney, respectively.

Answer 36

The blood supply to the testicles always comes from the testicular arteries that arise from the Aorta, even as they descend. The renal arteries that supply the kidney temporarily branched off the Common Iliac artery in early development. They degenerated and as the kidneys ascended the supply was replaced by renal arteries that branch off the Aorta.

Question 37

What congenital defect is caused by the failure of the urorectal septum to divide the cloaca into the urogenital sinus and rectum?

Answer 37

Persistent Cloaca