Session 2: embryology

Question 1

What is the functional unit of the kidney?

Answer 1

Nephron

Question 2

What is the definitive kidney called in the foetus?

Answer 2

Metanephros

Question 3

How is the metanephros formed?

Answer 3

Pronephros to the Mesonephros to the Metanephros

Question 4

Can the metanephros conserve water?

Answer 4

Yes. It can produce urine and conserve water.

Question 5

What is the pronephros?

Answer 5

• It is a duct.
• Extends from the cervical region to the cloaca
• Drives the development of the next developmental stage

Question 6

What is the urogental ridge?

Answer 6

Region of intermediate mesoderm giving rise to both the embryonic kidney and the gonad

Question 7

The mesonephric duct is capable of water conservation. True/False

Answer 7

False

Question 8

Where do the mesonephric tubules develop?

Answer 8

Closer to the tail (caudal) than to the pronephros region

Question 9

What is the embryonic kidney?

Answer 9

The mesonephric tubules and the mesonephric duct

Question 10

What is the role of the mesonephric duct in regards to development?

Answer 10

• Important role in development of the reproductive system in the male
• Sprouts ureteric bud which induces development of the definitive kidney

Question 11

What is the importance of the ureteric bud?

Answer 11

Induces the development of the true kidney (metanephros)

Question 12

How does the true kidney develop?

Answer 12

• Ureteric bud communicates with the metanephric blastema
• Bud expand and branches
• Formation of the collecting system from the ureteric bud
• The excretory component is derived from the intermediate mesoderm under the influence of the ureteric bud

Question 13

Where does the metanephric kidney first appear?

Answer 13

Pelvic region

Question 14

How does the kidney ascend from the pelvis?

Answer 14

• Undergoes an apparent caudal to cranial shift, crossing the arterial fork formed by vessels returning blood from the foetus to placenta
• The blood supply shifts upward by formation of new vessels and the old vessels are obliterated

Question 15

What happens if the old blood vessels aren’t obliterated as the kidney ascends?

Answer 15

They becomes accessory arteries which are end arteries.

Question 16

How can renal agenesis occur?

Answer 16

Ureteric bud fails to interact with intermediate mesoderm.

Question 17

What can go wrong with the development of the kidneys?

Answer 17

• Ureteric bud can fail to interact with intermediate mesoderm
• Migration can go awry
• Duplication defects
• Ectopic ureter
• Cystic disease

Question 18

What are structural anomalies associated with the kidney?

Answer 18

• Pelvic kidney

- Horseshoes kidney

Question 19

How is urogenital sinus created?

Answer 19

The cloaca becomes divided by urorectal septum into the urogenital sinus (and anorectalcanal)

Question 20

What does the urogenital sinus differentiate into?

Answer 20

• Superior part connect to the umbilicus
• Majority differentiates to form the urinary bladder
• Inferior part develops into the urethra

Question 21

How is the female urethra formed?

Answer 21

By the pelvic part of the urogenital sinus

Question 22

How is the male urethra divided?

Answer 22

• Pre-prostatic
• Prostatic
• Membranous
• Spongy

Question 23

How is the male urethra formed?

Answer 23

In a male, the genital tubercles elongates and genital folds fuse to form the spongy urethra.

Question 24

What is hypospadias?

Answer 24

• Defect in fusion of urethral folds

- Urethra opens onto the ventral surface rather than at the end of the glans where it normally is

Question 25

What is the overview of the development of the kidney?

Answer 25

1. Pronephros 2. Mesonephros appears and the pronephros disappears. Made of the wolfian duct or mesonephric duct. 3. Urethral bud is formed from mesonephric duct. Urethral bud is only for the major calyx, minor calyx, renal pelvis and collecting duct 4. Metanephros is formed from urethral bud. 5. 1/3 of the bottom nephrogenic cord becomes the metanephric blastema. This circles around the urethral bud. The mesonephros which is the rest becomes the genital components

Question 26

What is the bladder formed from?

Answer 26

The bladder is a hindgut derivative | -Derived from the caudal portion of the primitive gut tube.

Question 27

Explain the process of development from the allantois?

Answer 27

- Allantois is involved in the development of the bladder - It is a superoventral diverticulum of the handout and extends into the umbilical cord - Lumen of the allantois becomes obliterated to become the urachus - The urachus becomes median umbilical ligament in adults

Question 28

What is the significance of the accessory renal arteries being terminal or end arteries?

Answer 28

-If the accessory arteries are occluded then the part of the kidneys that they supply will be damaged due to the lack of the blood supply.

Question 29

Why would patients with ectopic urethral orifices complain of urinary incontinence?

Answer 29

- Urethra opens straight into the penis and leaks out | - The urine bypasses the urethral sphincter so therefore no control on urination

Question 30

What does abnormally amniotic fluid show?

Answer 30

The kidney function in the foetus is low so less excretion of urine

Question 31

What is pelvic kidney?

Answer 31

One of the kidney fails to ascend

Question 32

How does a horseshoe kidney form?

Answer 32

As the kidney ascend the bases touch and fusion starts to occur