-
Humans have _____ chromosomes, or _____ pairs?
46 chromosomes; 23 pairs
-
Pairs 1-22 are called _____.
Autosomes
-
The 23rd pair is the _____ _____.
Sex Chromosomes
-
The _____ determines the genetic sex of the child.
Father
-
The _____ _____ is contained in the Y Chromosome, and is the strongest determinant of sexual differentiation.
SRY Gene
-
The first 7 weeks are the _____ _____ period, in which the SRY gene has not made the determination between ovaries and testes.
Indifferent Gonad
-
The presence of 2 X Chromosomes (XX) or 1X and 1Y Determined at fertilization.
Stage 1 (Chromosomal Sex)
-
All eggs contain __________.
22 autosomes & 1X
-
All sperm contain _____.
22 autosomes & either 1X or 1Y Chromosome.
-
The presence of either ovaries or testes; determined by chromosomal sex.
Stage 2: Gonadal Sex
-
XX individuals form _____.
Ovaries
-
XY individuals form _____.
Testes
-
The conversion of the indifferent gonad into a testis or ovary.
Sex Determination
-
Begins development in late 3 wee old embryo and develops from two tissues.
The Indifferent Gonad (3-6 week)
-
2 masses of somatic cells (supporting & steroidogenic) that form medial to the embryonic kidneys (mesonephros).
Genital Ridges
-
Contained in the yolk sac of the embryo. Will migrate around the 6th week into the genital ridge. Develop into germ cells (oogonia or spermatogonia).
Primordial Germ Cells (PGC's)
-
Begins during the 7th week in XY embryo and is initiated by SRY gene on the Y Chromosome.
Formation of the Testis
-
Steroidogenic cells form the ______ cells.
Leydig
-
Leydig cells secrete ______.
Testosterone
-
Supporting cells form the ______ cells.
Sertoli
-
Sertoli cells secrete ______.
APH
-
Why are they called supporting cells?
Because they typically do not secrete hormones.
-
______ is very important for determining male internal genitalia.
APH
-
______ form the spermatogonia 2n.
PGC's
-
______ are arrested until puberty.
Spermatogonia 2n
-
Begins during the 10th-12th week in XX embryo.
Formation of the ovary
-
Formation of the ovary is initiated by ______.
Absence of the SRY gene.
-
In the formation of the ovary, the ______ gene is required to act on X.
DAX1
-
Suppresses DMRT1, DMRT2 & SOX9 genes during formation of the ovary.
DAX1 gene on X.
-
During formation of the ovary, steroidogenic cells will form ______ cells.
Theca
-
Theca cells synthesize ______.
Androgen
-
In formation of the ovary, supporting cells form ______, or ______ cells.
Follicle, or Granulosa
-
Follicle (Granulosa) cells convert ______ to ______.
Androgens to Estrogen
-
PGC's form ______.
Oogonia
-
Development of the internal & external genitalia.
Sexual Differentiation (Phenotypic)
-
______ ______ develop from paramesonephric ducts, mesonephric ducts & urogenital sinus.
Internal Genitalia
-
Mullerian ducts are ______.
Female
-
Wolffian ducts are _____.
Male
-
Paramesonephric ducts are also known as ______ ducts.
Mullerian
-
Mesonephric ducts are also known as ______ ducts.
Wolffian.
-
The XY (male) embryo develops ______ ______ during the 8th-11th weeks.
Internal Genitalia
-
In the paramesonephric (Mullerian) ducts, ______ is needed to degenerate the female hormone in order for the embryo to become a male.
APH
-
The mesonephric (Wolffian) duct is stimulated by ______ to form the ______, ______ & ______.
testosterone; epididymis, vas deferens & seminal vesicles.
-
______ ______ is gained in the epididymis and remain there until ready to be utilized.
Sperm motility
-
The ______ ______ is the transport for the sperm to the glands to form semen.
Vas deferens
-
The ______ ______ are the first pair of glands in the male system and contribute the most fluid to add to the sperm in the testes.
seminal vesicles
-
The absence of ______ in the paramesonephric (Mullerian) ducts allow the ______, ______ ______, and the ______ to begin to form.
APH; uterus, uterine tubes, and the upper 1/3 of the vagina to form.
-
Develop from progenitor tissues that appear during the sexually indifferent stage.
External Genitalia
-
In the XY embryo between 9-12 weeks, the penis is formed here.
Genital Tubercle
-
In the XY embryo, the urethra, prostate & bulbourethral glands are formed here.
Urogenital Sinus
-
In the XY embryo, the scrotum is formed here.
Urogenital Folds
-
______ and ______ act to form the external genitalia in the XY (male) embryo.
Testosterone and DHT
-
In the XX (female) embryo between 9-12 weeks, development of the external genitalia is ______.
autonomous
-
In the XX (female) embryo, the clitoris is formed here.
Genital tubercle
-
In the XX (female) embryo, the lower 2/3 of the vagina is formed here.
Urogenital sinus
-
In the XX (female) embryo, the Labia minora and Labia majora are formed here.
Urogenital folds
-
BOTH descend from their original positions high up in the abdomen.
Testes and Ovaries
-
Descent of the testes and ovaries depend on the _______.
gubernaculum (ligamentous cord)
-
Descent of the testes begins in the ______ month.
7th
-
In the XY (male) embryo, _______ and ______ cause shortening of gubernaculum (ligamentous cord).
Testosterone and APH
-
The ______ are completely descended by birth (95%).
Testes
-
______ is the failure of the testes to descend.
Cryptorchidism
-
An error of sex determination, in this individual the autosomal testis determining genes (DMRT1, DMRT2 & SOX9) is defective and not suppressed by DAX1.
XX (SRY-) Male
-
An error of sex determination, in this individual the SRY gene is absent (translocation error during meiosis).
XY (SRY-) Female
-
An error of sex determination, in this individual the SRY gene is defective.
XY (SRY+) Female
-
An error of sex determination, in this individual the SRY gene acts on the X chromosome (translocation error during meiosis)
XX (SRY+) Male
-
In ______ ______, both ovarian & testicular tissue is present in the same individual (XX or XY).
True Hermaphroditism
-
In true hermaphroditism, the individual is most always ______.
sterile
-
Formed by the yolk sac, then migrate from yolk sac to genital ridges and develop into germ cells (oogonia or spermatogonia)
Primordial Germ Cells (PGC's)
-
Arrival of ______ in genital ridges stimulates conversion of the indifferent gonad into a testis or ovary.
PGC's
-
Steroidogenic cells that secrete testosterone.
Leydig Cells
-
Supporting cells that secrete APH
Sertoli Cells
-
Steroidogenic cells that synthesize androgens
Theca cells
-
Supporting cells that convert androgens to estrogen
Follicle (Granulosa) cells
-
Chromosome pairs 1-22 are referred to as:
Autosomes
-
Formation of the ovaries requires which
of the following?
The absence of the SRY Gene
The DAX1 gene on each of the X chromosomes to suppress DMRT1, DMRT2, and SOX9 genes
-
The migration of ____________from the ____________ into the genital ridge of the embryo around the 4-5th week, begins
gonadal differentiation.
Primordial Germ Cells (PGC’s); yolk sac
-
Around the 7th week in the XY embryo, the 2 cell types of the genital ridge will form the
testes. What cells of the testes will the supporting cells become?
Sertoli cells
-
What hormone will the Leydig cells secrete?
Testosterone
-
Around the 10th week in the XX embryo, the 2 cell types of the genital ridge will form the
ovaries. What cells of the testes will the steroidogenic cells become?
Theca cells
-
Internal genitalia will form the
mesonephric and paramesonephric ducts
-
The Paramesonephric duct is also referred to as the _________ duct.
Mullerian
-
What internal genitalia will form in the female from the paramesonephric duct?
uterine tube
-
What hormones are required for the internal genitalia of the female to form?
No hormones
-
External genitalia will form the
genital tubercle, urogenital sinus, and urogenital folds
-
What is necessary in order for the urogenital sinus to form the urethra in the XY embryo?
DHT (dihydrotestosterone)
-
The urogenital folds form the ______________ in males and the ______________ in females.
scrotum; labia
-
What progenitor tissue later becomes the penis in males and the clitoris in the female?
genital tubercle
|
|