Embryonic Development of the UG System Flashcards
What differentiates into the pronephros, mesonephros and metanephros?
Nephrogenic cord
What does the nephrogenic cord develop into?
Pronephros, mesonephros and metanephros
When does the pronephros form?
4th week of embryological development
Where does the pronephric duct empty into?
Cloaca
When does the pronephros disappear?
6th week
What does the pronephric duct develop into?
Mesonephric duct
What is contained in the mesonephric duct?
Contains glomerulus and bowmans capsule
What does the metanephros develop from?
Uteric bud
Metanephric blastema
Mesonephric duct
What germ layer do the kidneys develop from?
Mesoderm
What does the uteric bud form?
Calyces
Collecting duct
Renal pelvis
Ureters
When do the kidneys begin to function?
Third month
When does the fetal period begin?
Week 9
What occurs in the first trimester of pregnancy?
The most important stage - organ systems begin to form.
When is the fetus most vulnerable to the effects of drugs, radiation and microbes?
The first trimester due to the extensive activity of this time.
Outline the 2nd trimester of pregnancy.
The development of organ systems is nearly complete and the fetus has human like features.
Outline the 3rd trimester of pregnancy.
A period of rapid fetal growth (weight of the fetus doubles) and organ system become fully functional.
What is the first excretory organ that forms in the fetus?
Mesonephros
When does production of urine begin in the mesonephros?
Week 6
What is the ureter anlage?
An epithelial outgrowth on the end of the mesonephric duct.
What is the ureter anlage the origin of?
Ureter
Minor and Major Calyces
Renal Pelvis
From what mesoderm do the kidneys develop from?
The intermediate mesoderm
What does the metanephric blastema of the metanephros develop into?
Proximal and distal tubules
Bowmans capsule
(Filtration-reabsorption system)
What is the uteric bud another name for?
Ureter anlage
What is the cloaca divided by?
Urorectal septum
What does the urorectal septum separate the cloaca into?
Anorectal canal
Urogenital sinus
What does the bladder develop from?
Urogenital sinus
What does the urethra’s in men and women develop from?
Urogenital sinus
What was the urogenital sinus form from?
Cloaca
What are the three sources the gonads develop from?
Intermediate mesoderm
Mesenchymal cells
Primordial germ cells
What gives rise to the male genital ducts?
Mesonephric ducts (aka Wolfian)
What gives rise to the female genital ducts?
Paramesonephric ducts (aka Mullerian)
What germ layer do the gonads form from?
Intermediate mesoderm
What protein is responsible for the sexual differentiation of the gonads?
SRY protein (sex determining region Y protein)
What do sertoli cells in the embryo differentiate into?
Seminiferous tubules
Testicular cords
What is the rete testis?
The rete testis is an anastomosing network of tubules located in the hilum of the testicle.
What does the rete testes do?
That carries sperm from the seminiferous tubules to the efferent ducts.
What cells secrete testosterone?
Leydig cells
Explain the descent of the testes.
The GUBERNACULUM is a cord that draws the testes down from the abdomen through the INGUINAL CANAL and into the scrotum.
What happens to the primordial germ cells?
- PGC migrate to the genital ridge where they undergo mitosis.
- PCG cells differentiate into oocytes and sperm cells.
What does the embryonic cortex develop into in men and women?
Seminiferous tubules in men
Ovarian follicles in women
What does the embryonic medulla develop into in men and women?
Rete testis
Rete ovarii
What does the embryonic genital tubercle develop into in men and women?
Penis
Clitoris
What do primordial germ cells differentiate into?
Sperm cells and Oocytes
What does the embryonic genital swelling develop into in men and women?
Scrotum
Labia Majora
From what germ layer does the urogenital sinus develop?
Endoderm
What does the Wolffian mesonephric duct develop into?
Epididymus
Vans Deferens
Seminal vesicle
Ejaculatory duct
What are the derivatives of the urogenital sinus in men?
Urethra
Bladder
Anorectal canal
What gender is the Wolffian mesonephric duct present in?
Men only
What gender is the Mullerian paramesonephric duct present in?
Female only
What does the Mullerian paramesonephric duct develop into?
Uterus
Fallopian tube
Vagina (3/4)
What does the urogenital sinus develop into in women?
Vagina (1/4)
Urethra
Vaginal vestibule
Bladder
How does the genital tubercle form, and when?
The fusion of cloacal folds in the 5th week
What do the cloacal folds develop into and when?
Genital tubercle (5th week) Urethral folds (7th week) Anal folds (7th week) Genital swelling
What does the penis form from?
The genital tubercle
When does the cloaca subdivide forming the anorectal canal and urogenital sinus?
5th week
What does the clitoris form from?
Genital tubercle
What do the genital swellings in women form?
Labia majora
What forms the labia minora?
Urethral folds
From what germ layer does the urogenital sinus develop?
Endoderm
What is the embryonic remnant of the gubernaculum in the women?
Round ligament
What is capiciation?
Activation of the acrosomal head of sperm when it penetrates the corona radiata.
Capacitation causes the release of what?
Acrosin and esterases which break down the cell membrane of the oocyte.
What happens when sperm bind to integrisin?
It initiates the cortical