From where do primordial germ cells arise?
From the wall of the yolk sac.
What happens to the testis cords during development?
They lose their connection with the surface epithelium and become separated by tunica albuginea.
Where do interstitial cells of Leydig lie?
Between the testis cords.
p.11
Fate of the Processus Vaginalis
What is the processus vaginalis associated with?
An evagination of a peritoneal pouch with the testis.
Where is the genital ridge located?
On the medial side of the mesonephros.
p.16
Anomalies of Male External Genitalia
What is hypospadias?
A condition due to incomplete fusion of the urethral folds, resulting in an abnormal urethral opening.
p.1
Formation of Indifferent Gonads
What are the three parts that form the gonad?
1. Stroma of the gonad 2. Trabeculae (primitive sex cords) 3. Primordial germ cells.
p.6
Development of Male External Genitalia
What is the role of testosterone produced by Leydig cells?
It influences the development of genital ducts and external genitalia.
What are interstitial cells of Leydig derived from?
The original mesenchyme of the gonadal ridge.
What shape do testis cords take in the 4th month of development?
Horseshoe-shaped (seminiferous tubules).
What happens to the mesonephric duct in females?
Refer to the development of the ovary.
What is the origin of the stroma of the gonad?
It is formed from intermediate mesoderm.
p.12
Descent of the Testis
What are the two main causes of descent of the testis?
Growth and retraction of gubernaculum, and increase of intra-abdominal pressure due to growth of abdominal organs.
p.10
Descent of the Testis
To what structure is the gubernaculum attached caudally?
The floor of the scrotum.
What do the proliferating epithelial cells form in the genital ridge?
They form the primitive sex cords.
What does the rete testis become continuous with?
15-20 mesonephric tubules.
When do interstitial cells of Leydig start testosterone production?
By the 8th week of development.
p.10
Descent of the Testis
Where is the gubernaculum attached in relation to the developing testis?
To the lower pole of the developing testis.
p.9
Development of Male External Genitalia
Which duct is responsible for the formation of the ejaculatory ducts in males?
The mesonephric (Wolffian) duct.
p.13
Development of Male External Genitalia
What happens to the urethral folds during the elongation of the phallus?
They are pulled forward to form the penile urethra.
What happens to the testis cords towards the hilum of the gland?
The cords break up, forming the tubules of the rete testis.
p.16
Anomalies of Male External Genitalia
Where can the abnormal urethral opening in hypospadias occur?
It can be near the glans penis, along the shaft of the penis, or near the base of the penis.
p.9
Development of Male External Genitalia
What are the male derivatives of the mesonephric (Wolffian) duct?
Efferent ductules, Epididymis, Vas deferens, Seminal vesicles, Ejaculatory ducts.
p.17
Anomalies of Male External Genitalia
What condition may be associated with epispadias?
Exstrophy of the bladder.
p.16
Anomalies of Male External Genitalia
What causes hypospadias?
Incomplete fusion of the urethral folds.
What do the primitive sex cords form during the development of the testis?
They proliferate and penetrate deep into the medulla, forming the testis (medullary) cords.
What do the efferent ductules connect?
The rete testis and the mesonephric (Wolffian) duct.
p.1
Formation of Indifferent Gonads
What are trabeculae in the context of gonad formation?
They are also known as primitive sex cords.
From where are Sertoli cells derived?
From the surface epithelium of the gland.
p.13
Development of Male External Genitalia
What structure is formed from the elongation of the genital tubercle?
The phallus, which will form the penis.
p.11
Fate of the Processus Vaginalis
What happens to the proximal part of the processus vaginalis?
It becomes obliterated, forming a vestige of the processus vaginalis.
What do the mesonephric tubules develop into?
Efferent ductules of the testis.
p.17
Anomalies of Male External Genitalia
Where is the urethral opening located in epispadias?
On the dorsum of the penis.
p.17
Anomalies of Male External Genitalia
Can epispadias occur as an isolated defect?
Yes, it may occur as an isolated defect.
What is the role of primordial germ cells in gonad development?
They have an inductive influence on the development of the gonad into ovary or testis.
From where are spermatogonia derived?
From primordial germ cells.
p.1
Formation of Indifferent Gonads
What is the stroma of the gonad?
It is one of the three parts forming the gonad.
What are the two types of cells that compose the walls of seminiferous tubules?
Sertoli cells and spermatogonia.
p.18
Anomalies of Male External Genitalia
What are the two types of phimosis?
Congenital (physiological) and pathological (caused by scarring).
p.13
Development of Male External Genitalia
What hormone influences the elongation of the genital tubercle during male external genitalia development?
Androgens secreted by the fetal testes.
p.13
Development of Male External Genitalia
What do the genital (scrotal) swellings develop into?
The two halves of the scrotum.
p.12
Undescended Testis (Cryptorchidism)
When does the testis typically descend in most cases of undescended testis?
During the first 3 months of life.
p.18
Anomalies of Male External Genitalia
What is phimosis?
Difficulty in retracting the skin of the prepuce over the glans penis.
What is the origin of the primitive sex cords in indifferent gonads?
They are derived from coelomic epithelium.
What do the epithelial cells of the coelomic cavity do?
They proliferate and penetrate the underlying mesoderm of the genital ridge.
p.9
Development of Male External Genitalia
What is the significance of the mesonephric duct in males?
It gives rise to several structures including the epididymis and vas deferens.
p.1
Formation of Indifferent Gonads
What role do primordial germ cells play in gonad formation?
They are one of the three essential components forming the gonad.
