Flashcards in Chapter 19: Male and Female Reproductive System Deck (16):
Without Testosterone = female anatomy
With Testosterone = male anatomy
Genetic males without testosterone receptors = female body
Lack ovaries and do not menstruate.
Testosterone during and after Puberty
Puberty range (8-14 years old): testosterone stimulates development of secondary sexual characteristics:
General growth of body and genitalia, ↑libido (sexual drive), ↑erythropoiesis, ↑frequency of erections and ejaculations
Process of making sperm
Androgen binding protein (ABP) must be present
GnRH - Gonadotropic Releasing Hormone
Gonadotropic Releasing Hormone (hypothalamus) normally regulated by a negative feedback loop,
During puberty - hypothalamus less sensitive to high testosterone levels,
(Sustentacular or nurse cells)
Secrete ABP (permissive to testosterone)
Leydig Cells (Interstitial cells)
Inhibin decreases Sperm Count
Normal sperm count ranges between 20-140 million sperm per ml of ejaculate.
Inhibin - selectively inhibits FSH but not LH or testosterone, this mechanisms decreases [ABP] to regulate sperm count while maintaining other characteristics.
Contains digestive enzymes that breakdown the ovum’s zona pellucida (glycoproteins)
Once it crosses, it must then deliver its nucleus into a ‘receptive’ secondary oocyte
requires two gametes (sperm and ovum) each has to be haploid (n)
The formation of spermatozoa (takes ~64-74 days).
Testosterone stimulates Spermatogenesis (ABP must be present)
Mature Spermatozoon Characteristics
Very little cytoplasm and organelles
Genetic material (n=23 chromosomes),
Acrosome has lysosomes with digestive enzymes (Helps penetrate the ovum)
Midpiece (body): numerous mitochondria
Produce ATP for locomotion.
Microtubules for locomotion,
Principal Piece: Largest part of tail.
End piece: Smallest part of tail
Puberty onset 10 – 16 years of age
Estrogen (from ovary),
Gonadotropin releasing hormone (GnRH) from hypothalamus stimulates:
FSH and LH secretion from adenohypophysis,
FSH - stimulate oogenesis of a dominant oocyte,
LH - followed by ovulation and menstruation in each cycle
Secondary oocyte development during puberty
Ovarian Cycle (in ovary)
Follicular phase (day 1 -13): Graafian Follicle Develops (with Secondary oocyte inside)
Ovulation (day 14): 2nd oocyte leaves ovary
Luteal phase (day 15 – 28): Follicle becomes corpus luteum and produces Progesterone and Estrogen