Embryology of Systems

Question 1

Where does the development of the urogenital system begin

Answer 1

urogenital ridge (mesoderm)

Question 2

Explain the process of development of the development of the nephrite ducts

Answer 2

1. Pronephros
2. Mesonephros
   ○ Interim kidney roles
   ○ degenerates
3. Metanephros
   ○ Uteric buds
   ○ Induces intermediate mesoderm to form metanephric blastema

Question 3

What does the metanephros develop into and what is the rest of the kidney derived from

Answer 3

ureters, calcyes, renal pelvis and collecting ducts

The rest of the kidney is derived from the metanephric mesenchyme

Question 4

Give examples of abnormalities of renal migration

Answer 4

Pelvic kidney
Horseshoe kidney
Aberrant renal arteries

Question 5

During gonadal development where do primordial germ cells migrate to and from

Answer 5

from the yolk sac wall to the genital ridge

Question 6

What does the mesonephric and paramesonephric duct differentiate into during gonadal ductal differentiation

Answer 6

Mesonephric duct - Wolffian duct

Paramesonephric duct - Mullerian duct

Question 7

Explain what occurs in ductal differentiation in the presence of the SRY gene

Answer 7

Wolffian duct remains and differentiates

Mullerian duct disintegrates

Question 8

Explain what occurs in ductal differentiation in the absence of the SRY gene

Answer 8

Wolffian duct disintegrates
Mullerian duct remains and differentiates
Mullerian ducts fuse in the middle to form the uterus and upper 1/3 of the vagina

Question 9

What occurs prior to cardiac development

Answer 9

the extra-embryonic mesoderm is initially a crescent shape.
It folds and separates into two blood vessels (cardiac tubes).
These tubes fuse and form the primitive heart tube.

Question 10

What occurs during heart development before septum formation

Answer 10

The primitive hear tube folds backwards on itself

Question 11

Describe the process of septum formation

Answer 11

1. Between atria and ventricles, endocardial cushions, from either side will form and fuse
2. Septum primum forms and joins the endocardial cushion
3. Septum secundum forms above and below the septum primum
4. Muscular intraventricular septum forms from below

Question 12

Explain how the circulation system of the heart develops

Answer 12

Before birth, the foetus receives blood from the placenta (veins are oxygenated). There is a ductus arteriosus between aortic arch and pulmonary artery

Immediately after birth the ductus arteriosus constricts so all the blood leaving the right ventricle travels to the lung via the pulmonary artery
The foramen ovale closes, leaving the fossa ovalis

Question 13

What is the order of lung structure development

Answer 13

1. Embryonic
   
   2. Pseudoglandular
   3. Canalicular
   4. Saccular
   5. Alveolar

(Every Premature Child Seeks Air)

Question 14

Describe limb development

Answer 14

1. Limb bud
   
   2. Hand/food plates
   3. Digits

Involves three processes: Proliferation, apoptosis and differentiation
The upper limbs will begin development first