3. Embryology: Urogenital Ridge + Kidney

Question 1

Define cloaca

Answer 1

The most caudal part of the primitive hindgut, where the excretory ducts of both the reproductive + urinary systems open into

Question 2

3 stages of kidney development?

Answer 2

1. Pronephros
2. Mesonephros
3. Metanephros

Question 3

Where does the intermediate mesoderm lie and what does it develop?

Answer 3

Lies between paraxial mesoderm and lateral plate mesoderm.

Develops the urinary and reproductive systems

Question 4

Which mesoderm are somites associated with?

Answer 4

Paraxial mesoderm

Question 5

Which mesoderm is the coelom associated with?

Answer 5

Lateral plate mesoderm

Question 6

The ureteric bud forms:

Answer 6

1. Ureter
2. Renal pelvis
3. Major calyces
4. Minor calyces
5. Collecting ducts

Question 7

The metanephric mesoderm forms:

Answer 7

1. Glomerulus
2. Bowman’s capsule
3. Proximal convoluted tubule
4. Loop of Henle
5. Distal convoluted tubule

Question 8

What causes the kidney to ascend?

Answer 8

Growth of ureters

Question 9

Pelvic kidney?

Answer 9

Kidney located in pelvis (instead of abdomen) because it fails to ascend during fetal development

Question 10

Aberrant renal arteries?

Answer 10

Aberrant arteries from renal artery perforate parts of kidney other than hilum

Question 11

Horseshoe kidney?

How common?

Answer 11

Caudal ends of kidneys fuse in midline until blocked by inferior mesenteric artery.

90% of fused kidneys = horseshoe

Question 12

Polycystic kidney?

Answer 12

Congenital condition, where nephrons fail to join together collecting tubules. This causes enlargement of kidneys as urine accumulates and causes formation of cysts.

Question 13

Retrocaval ureter?

Answer 13

During ascension, ureteric bud passes behind inferior vena cava, which could cause the vein to compress the ureter, thus causing hydronephrosis

Question 14

Megaureter?

Answer 14

Increased diameter of ureter with no peristalsis due to lack of smooth muscle, causing stagnation of urine, thus infection

Question 15

Ectopia vesicae / Extrophy of bladder?

Answer 15

Urinary bladder opens up onto anterior abdominal wall

Question 16

What is the urachus?

Answer 16

Fibrous remnant of allantois, which joins the bladder to the umbilicus

Question 17

Define cyst

Answer 17

An abnormal closed cavity, lined by epithelium, usually containing liquid

Question 18

Define fistula

Answer 18

An abnormal communication between 2 internal organs or between an internal organ and surface of body

Question 19

Define sinus

Answer 19

An abnormal communication between an abnormal cavity and the surface of the body

Question 20

What makes up the urogenital ridge?

Answer 20

Gonadal ridge + Mesonephros = Urogenital ridge

Question 21

Where do the testis come from?

Answer 21

Mesonephros

Question 22

Describe the descent of the testis

What is the Processus Vaginalis?

Answer 22

The gubernaculum (fibrous cord) attaches the lower pole of the testis to the lower abdominal wall. It anchors the testis as it interrupts the developing muscles (forming the inguinal canal). The anchoring pulls down testis as fetus grows and eventually reaches scrotum by time of birth.

The Processus Vaginalis is a small outpouching of peritoneum (which is pulled into the scrotum)

Question 23

What makes up the spermatic cord?

Answer 23

1. Vas deferens + testicular vessels
2. Nerves
3. Lymphatics