5/31 Lecture E3 Flashcards
what are gametes?
sex cells (one from each parent)
what is a zygote?
a fertilized egg (contains genes from both parents)
What chromosome is male?
the Y
what is the male copulatory organ?
penis
What is the female copulatory organ?
vagina
What are the primary sex organs that produce gametes?
testes or ovaries
What are the secondary sex organs?
organs other than gonads that are necessary for reproduction:
male: system of ducts, glands, penis
female: uterine tubes, uterus, and vagina
Where are the external genitalia located?
in the perineum
What are the secondary sex characteristics?
features that distinguish the sexes and influence mate attraction
When do secondary sex characteristics develop?
at puberty
how many pairs of chromosomes are contained in cells?
23
How many pairs of autosomes are contained in cells?
22
How many pairs of sex chromosomes are contained in cells?
1 (XY for males; XX for females)
How is the sex of a child determined?
by the type of sperm that fertilizes the mother’s egg, whether X-carrying or Y-carrying
When do gonads develop in a fetus?
at 5-6 weeks; as gonadal ridges
how many sets of ducts are adjacent to each gonadal ridge?
2
In males, which ducts develop and which ducts degenerate?
mesonephric (wolfian) develop
paramesonephric (Mullerian) degenerate
In females, which ducts develop and which ducts degenerate?
paramesonephric (Mullerian) develop
mesonephric (wolfian) degenerate
What is the SRY gene?
the Sex-determining Region of Y chromosome
What does the SRY gene code for?
a protein, testes-determining factor (TDF) that initiates development of testes
When do the testes begin to secrete testosterone?
8-9 weeks
What else do the testes secrete during development (besides testosterone)?
mullerian-inhibiting factor/substance (MIS)
What does the genital tubercle become?
either the glans of the penis, or the glans clitoris
What does the pair of urogenital folds form?
either encloses the male urethra to help form the penis, or forms the labia minora
What do the pair of labioscrotal folds form?
either the scrotum or labia majora
By when are the male/female genitalia distinctly formed?
week 12
Male and female organs that develop from the same embryonic structure are called ____?
homologous
that is the glans penis homologous to?
the clitoris
what is the scrotum homologous to?
the labia majora
what is the penis homologous to?
the labia minora
what is the gubernaculum?
embryonic connective tissue cord extending from goand to pelvic cavity floor
What is the vaginal process?
fold of peritoneum that extends into the scrotum
What is the inguinal canal?
the pathway of low resistance through the groin created by gubernaculum and vaginal process
What is the most common site of hernia in males?
the inguinal canal
When does descent of the testes begin?
as early as 6 weeks
What is the path of the testes?
inguinal canal –> scrotum by way of the gubernaculum
When do the testes pass through the inguinal canal?
the 7th month
What muscle accompanies the testes?
extensions of the internal abdominal oblique muscle
What is cryptorchidism?
undescended testes
in how many male births does cryptochidism occur?
about 3%
What happens if cryptochidism remains uncorrected?
sterility or testicular cancer
Where do ovaries get lodged?
on the inferior brim of the lesser pelvis
In females, what does the gubernaculum become?
a pair of ligaments that supports the ovary and the uterus
What borders the external genitalia?
the pubic symphysis, ischial tuberosities, and the coccyx
which testicle is typically lower
the left
What divides the scrotum into right and left compartments?
the internal median septum
What is the perineal raphe?
the medial seam on scrotum surface that marks the location of the median septum
