By week 4, the tiny human looks like a tube within a tube, with the outer one being the ____ and the inner tube being the _____
Body wall
Gut
Which part of the gut tube will be involved in GU development?
Caudal-most portion
The first 6 week of post-fertilization is considered as _____ state
Indifferent state for genital development
No difference between male and female genital system for the first six weeks
Male gonads will initially develop in the _______, and reaching the _____ by week 12. Migrating around it around week 28, and reach the ______ around week 33
Abdomen and descend
Reach the inguinal region
Scrotum
Structure found within the testes?
Seminiferous tubules – where sperm production is happening
Where does sperm production occur?
Seminiferous tubule
T/F: sperm production occurs in the epididymis
False; it is the seminiferous tubules within the testes
What connects the seminiferous tubule to the epididymis?
Rete testes by way of the efferent ductules
T/F: the first six weeks of development are consider to be the indifferent stage therefore chromosomal sex of the individual is not yet determined at that point
False; while its true it is indifferent, the chromosomal sex of the individual IS determined at fertilization
Which part of the mesoderm gives rise to parts of the urinary and genital systems?
Intermediate mesoderm
Intermediate mesoderm gives rise to:
Urogenital system
Gonads
Ducts
Seminal vesicles
Upper vagina
T/F: mesoderm, specifically intermediate mesoderm, and endoderm give rise to the vagina
True; intermediate mesoderm gives rise to upper vagina while endoderm gives rise to lower vagina
Endoderm gives rise to which GU parts?
Prostate
Lower vagina
Bulbourethral glands/ greater vestibular glands
Embryo folding where the head and tail bends towards each other is the ____ folding. While left and right side of embryo migrating towards midline, fusing and forming a cylindrical embryo is _____ folding
Craniocaudal
Lateral
The longitudinal elevation of intermediate mesoderm is the ______
Urogenital ridge
T/F: urogenital ridge gives rise to parts of the urinary and genital systems?
True
Where is the gonadal ridge in relation to the urogenital ridges?
medial surface of the urogenital ridges
Precursor to sperm and eggs are called?
Germ cells
T/F: Gonads are initially identical in male and female embryos
True; presence of XY chromosome complex will induce the indifferent gonads to develop into testes
T/F: Primordial germ cells are initially located in the gonads and stay there until fertilization
False; primordial germ cells are not initially in the gonads, they have to travel there from the gut
How does primordial germ cells migrate?
From the hindgut through dorsal mesentery to the dorsal body wall and into the genital ridges via pseudopodal activity
Who is indifferent gonad’s influencer to tell them to develop into testes?
primordial germ cells
Testis determining factor gene on Y sex chromosome
In week 6 of embryonic development, _______cords form _______ cords in male
Primitive sex
Medullary aka testis cords
In week 6 of female embryonic development, ______ cords form _______
Primitive sex cords
Cell clusters
T/F: primitive sex cords do not continue to extend and form medullary in XX female (no Y chromosome), instead the primitive sex cords will break up into cell clusters
True; the epithelium will continue to proliferate forming a second generation of epithelia extensions called cortical cords
The primordial germ cells in female will become _____ and the epithelial cells from the cortical cords surround the oocytes are called _____ cells
The eggs- oocytes
Follicular
Rete tests develop in week ___
8
Leydig cells also develop in week 8
T/F: Leydig cells start producing testosterone in week 8
True
What structure ultimately forms the seminiferous tubules?
testis cords aka medullary cords
Initially, seminiferous tubules do not have lumen, they are ______, but changes to having a lumen at ____
Solid
Puberty
Testis reach the inguinal region by week___, and migrate through the inguinal canal by week _____ and reach the scrotum by week _____
12
28
33
What structure help guide tests their descent to the scrotum?
Guberaculum (extends from the inferior pole of the testes)
What is the term used to describe when the testes do not descend to the scrotum by birth?
Cryptorchidism
What is cryptorchidism?
Failure of one or both testes to descend into the scrotum by birth
Leydig cells develop from _____
Mesenchyme
What separates testes from surrounding tissue?
Tunica albuginea
In the indifferent stage (week 6), what are the two sets of ducts that develop in the urogenital ridge of the embryo?
Mesonephric ducts- male structures
Paramesonephric ducts- female structures
Mesonephric duct is also known as _____ duct; paramesonephric duct is aka ____
Wolffian duct
Mullerian duct
T/F: mesonephric ducts give rise to the ureter in BOTH male and female
TRUE! Even though mesonephric duct gives rise to male parts, but it also has components for kidney development
Mesonephric duct gives rise to:
Ureter (male and female)
Male structures: efferent ductules, epididymis, vas deferns, seminal vesicle, ejaculatory ducts
T/F: male ducts/glands ae derived from the urogenital sinus (endoderm origin)
True
Cloaca becomes:
Bladder
Prostate
Bulbourethral glands
Most of the male urethra
T/F: signaling from the fetal testes causes mesonephric ducts to degenerate and paramesonephric ducts to persist
False; paramesonephric degenerates and mesonephric duct presits
External genitalia will first appear as some structures in the ____ Region of the embryo
Cloacal membrane
T/F: both males anfe females have a genital tubercle, a cloacal fold adjacent to the cloacal membrane
True
What is hypospadias?
Congenital condition that can occur if paired tissues that become the penis and scrotum fail to fuse.
May lead to abnormal openings at some point along the male urethral tract
What condition results when the paired tissue that become the ventral aspect of the penis and scrotum don’t fuse?
Hypospadias
Testosterone via ______ can be converted to DHT, which stimulate the growth of ____
5 alpha reductase
Male external genitalia
Genital tubercle enlarges to become ____ and genital swellings become _____
Phallus
Scrotal swellings
Where do urethral folds and scrotal swellings meet?
Midline
Medullary cords develop, no cortical cords and thick tunica albuginea, describe ______
Testis
Medullary cords degenerate, cortical cords develop and no tunic albuginea describe _____
Ovary
T/F: in females, primitive sex cords dissociate along with cortical cords
False; second generation cortical cords develop in female, while primitive sex cords do dissociate. Exact opposite of XY male
Urogenital sinus, anterior portion of the cloaca, gives rise to _______ in females
Bladder
Urethra
Lower vagina
Paraurethral glands
Greater vestibular glands
Paramesonephric ducts contribute to the formation of:
Vagina
Entire uterus
Uterine tubes
What is the unique signal that tells indifferent gonad to become an ovary?
WNT4
And the absence of Y chromosome
Which cell produce Mullerian inhibiting substance?
Sertoli cells
T/F: mesonephric ducts largely degenerates in female
True; though it does contribute to ureter formation in female
Inferior vagina came from _____ sinus; uterine tubes came from ________, and uterus, cervix and superior vagina came from ___
UG sinus (inferior vagina)
Unfused parts of paramesonephric (uterine tubes)
Fused parts of paramesonephric ducts
Uterine defect as a result of incomplete fusion of paramesonephric ducts is known as:
Bicornate uterus
T/F: urethral folds will not fuse in female embryo development and the genital swellings will not meet on the midline like they do in male
True
In female, urethral folds stays apart, giving rise to _____
Labia minora
Genital swellings become labia majora
Genital tubercle in female _______ elongate, becomes the ______