Development of the Reproductive System and Pituitary Gland Flashcards
Functionally the urogenital system can be divided into what two entirely different systems?
The urinary and the genital system
The urogenital system is derived from what embryonic tissue?
Intermediate mesoderm
What is the urogenital ridge?
This is intermediate mesoderm that bulges into the intraembryonic coelmic cavity
The urogenital ridge differentiates into what two things?
Nephrogenic cord/ridge and genital ridge
Primordial germ cells originate from what?
Endoderm of the yolk sac
What happens if the primordial germ cells do not migrate to or reach the genital ridge?
The gonads do not develop
How are the primitive sex cords formed?
Epithelium proliferates and epithelial cells penetrate underlying mesenchyme
Primitive sex cords can also be called what?
Gonadal cords
During the indifferent gonad phase, both males and females have what two ductal systems?
Mesonephric (Wolffian) ducts and paramesonephric (Mullarian) ducts
The Y chromosome has what gene that codes for what hormone?
SRY (sex determining region of the Y chromosome) gene that codes for TDF (testes determining factor) hormone
Under influence of TDF, primitive sex cords continue to proliferate and penetrate into the medulla and form what?
The testes (medullary cords)
Towards the hilum the testes cords will break up giving rise to what?
The tubules of the Rete Testis
What is the tunica albuginea?
Fibrous connective tissue that separates the testes cords from surface epithelium
The testes cords are composed of what two things?
Primitive germ cells and sustentacular cells (sertoli cells)
What do the sustentacular (sertoli) cells secrete?
AMH, antimullerian hormone
What does AMH cause?
The degradation of paramesonephric (mullarian) duct
What are interstitial (Leydig) cells?
These are a cell population found between the testis cords
What are interstitial (Leydig) cells derived from?
Mesenchyme from the genital ridge
What do interstitial (Leydig) cells secrete?
Testosterone
The testes cords remain solid until puberty forming what?
Seminiferous tubules
The ductuli efferentes connects what two things?
Rete testis and mesonephric duct
The ductuli efferentes will become what?
Ductus deferens (vas deferens)
The genital ducts are stimulated to develop by what?
Testosterone
Genital ducts in males are derived from what?
Mesonephric kidney system
The mesonephric duct opens into what?
Into urogenital sinus on either side of the sinus tubercle
The genital ducts in males forms what four things?
Epididymes, Ductus deferens, seminal vesicle, and ejaculatory duct
Under AMH the paramesonephric duct degenerates except what part?
A small part of the cranial end called the appendix testes
The testes start out intra or retroperitoneal?
Retroperitoneal
What do the testes pass through as they descend into the scrotum?
Inguinal canal
What is the gubernaculum?
This is a structure that anchors the testes to the scrotum and guides its decent
As the testes pass through the inguinal ring it gets covered by what four things?
Processus vaginalis, transversalis fascia, internal abdominal oblique muscle, external abdominal oblique muscle
What muscle does not contribute to a layer of the testes?
Transverse abdominus muscle
In female development what gene is missing and therefore what hormone is not produced?
SRY gene is absent so no TDF is produced
What gives rise to the cortical cords in developing females?
Surface epithelium continues to proliferate
What are the follicular cells?
These are the cells that surround primary oocytes (oogonium)
Why doe the mesonephric ducts degenerate and the paramesonephric ducts develop into main genital ducts in developing females?
A presence of estrogen and the absence of testosterone and AMH
Paramesonephric ducts connect at the midline and the caudal tip of the combined ducts project into urogenital sinus which is up against what structure?
Sinus tubercle
When the ovaries descend, the paramesonephric ducts form what 5 things?
Uterine tube, uterine canal, corpus uteri, cervix, upper portion of vagina
What are the vaginal fornices?
Wing like expansions of vagina around the end of the uterus
Cranial genital ligament forms what?
Suspensory ligament
Caudal genital ligament forms what?
Ligament of the ovary and round ligament of the uterus
What is the layer of tissue that will not be present in developing female genitalia?
Tunica albuginea
What are the cloacal folds?
During week three mesenchyme from primitive streak migrate around cloacal membrane to form the cloacal folds
What is the genital tubercle?
Folds fuse cranial to cloacal membrane to form the genital tubercle
Caudal folds in the developing genitalia form what two things?
Urethral and anal folds
The genital swellings form what in males and females?
Males: scrotal swellings
Females: labia majora
What is the urethral plate?
This is the epithelial lining of the urethral groove
What is the penile urethra?
The two urethral folds close over the urethral plate and form the penile urethra
What is the scrotal septum?
Line of fusion of scrotal swellings
In females the genital tubercle elongates slightly to form what?
Clitoris
In females the urethral folds do not fuse and thus form what?
Labia minora
In females the urogenital groove is open and thus forms what?
The vestibule
The pituitary glad is derived from what two structures?
Ectodermal outpocketing of stomodeum (Rathke’s pouch) and downward extension of diencephalon (infundibulum)
Adenohypophsis comes from what?
Cells in anterior wall of Rathke’s pouch
Pars intermedia is formed from what?
Posterior wall of Rathke’s pouch
The pars nervosa and stalk of the pituitary gland are derived from what?
Infundibulum
The anterior lobe of the pituitary is also called what?
Adenohypophysis
The posterior lobe of the pituitary is also called what?
Pars nervosa
