reproductive endocrinology 1 Flashcards
what is the reproductive system needed for?
Not required for maintaining homeostasis or survival of an individual but essential for the survival of the species
what is the main role of the male reproductive system?
to manufacture male gametes called sperm and deliver them to the female reproductive tract where fertilisation can occur.
what is the main role of the female reproductive system?
in addition to producing female gametes called Ova or egg, the female system is equipped to house and nourish the offspring to a developmental point until it can survive independently in the external environment
what are the primary reproductive organs in the males?
testes
what are the primary reproductive organs in females?
ovaries
what do the primary reproductive organs produce?
Gametes (sperm and ova)
Sex hormones
Testosterone in the male
Estrogens and progesterone in the female
what are the accessory reproductive organs?
Reproductive tract
Accessory sex glands
External genitalia
Breast in the female
what does the male reproductive system consist of?
Testes Epididymis Ductus deferens or Vas deferens Ejaculatory duct Urethra
what are the accessory sex glands in the male reproductive system?
Seminal vesicles
Prostate gland
Bulbourethral gland or Cowpar’s gland
what are the external genitalia of the male reproductive system?
the scrotum and the penis
what is the role of the scrotum?
Holds testes outside abdominal cavity at ~ 3ºC below body temp
what is the role of the penis?
Copulatory organ which deliver sperm into female reproductive tract
what does each testes consist of?
seminiferous tubules
leydig or interstitial cells
where are the seminiferous tubules found?
250-300 lobules containing 1-4 tightly coiled seminiferous tubules
what are the functions of leydig/interstitial cells?
secrete testosterone
what is the route that sperm takes?
Seminiferous tubules –>
Epididymis –> Vas deferens –> Ejaculatory duct –> Urethra
what is spermatogenesis?
production of the male gametes - the sperm
where does spermatogenesis take place?
in seminiferous tubules of the testes
which cells of the seminiferous tubules that are involved in spermatogenesis?
Germ cells
Sertoli cells
what is the process of spermatogenesis?
process by which undifferentiated germ cells, the spermatogonia , proliferate and are converted to spermatozoa (sperm).
how many chromosomes in a spermatogonia?
diploid - 46 chromosomes
how long does spermatogenesis take?
64-72 days
what are the 3 major stages of spermatogenesis?
Mitotic proliferation (forming spermatocytes)
Meiosis (Spermatocytes to spermatids)
Packaging or spermiogenesis (spermatids to sperm)
what are functions of Sertoli cells?
- Form blood-testicular barrier
- Provide nourishment to developing sperm
- Phagocytose cytoplasm extruded from the spermatids
- Secrete seminiferous tubule fluid into the lumen
- Sertoli cells secrete Androgen Binding Protein (ABP) which binds testosterone, required to maintain high level of testosterone in the seminiferous tubules
- Site of action of testosterone and FSH to control spermatogenesis
- Release inhibin which acts in negative-feedback fashion to regulate FSH secretion
how does sperm gain motility?
when they pass through the epididymis
what happens during ejaculation?
sperm are expelled through the urethral opening together with the secretion of accessory sex glands
what do foetal testis secrete?
testosterone which direct masculine development of reproductive tract
what happens to testis after birth?
testes becomes quiescent until puberty
what happens to hypothalamus during the peripubertal period?
hypothalamus is under neural inhibition and is extremely sensitive to negative feedback effect of testosterone
what happens to hypothalamus during puberty?
the neural inhibition is removed and hypothalamus become less sensitive to testosterone
how long does the maturation of brain testicular axis take?
3 years
what is the role of testosterone?
Stimulation of lineal body growth
Induction of secondary sexual characteristics
what does the female reproductive system consist of?
Ovaries Uterine or Fallopian tube Uterus Cervix Vagina
what is the external genitalia in the female reproductive system?
valva
Labia majus
Labia minus
Clitoris
what is different about the urethra in females than males?
Urethra is much shorter in female and urethral opening is separate from the opening of the reproductive tract, the vaginal orifice.
when is a females total supply of eggs determined?
at birth
what happens to oogonia in the foetal period?
the oogonia multiply rapidly by mitosis, become primordial follicles, and then become primary follicles that begin the first meiotic division
what happens in the female reproductive system after puberty?
a few oocytes are activated each month but only one will continue to meiosis I.
what happens to the oocyte in meiosis I?
2 haploid cells are produced - a polar body and a secondary oocyte.
what happens to the secondary oocyte?
stops in metaphase II and if a sperm penetrates it, it will complete meiosis II, producing a second polar body and a large ovum
what is the ovarian cycle?
Monthly series of events that take place in the ovaries, which are associated with the maturation of the egg
what are the 2 phases of the ovarian cycle?
- follicular phase
- luteal phase
what happens in the follicular phase?
The period of follicular growth typically lasting from day 1 to 14.
Produce mature oocyte ready for ovulation at midcycle
what happens in the luteal phase?
The period of corpus luteum activity lasting from day 14 to 28.
Prepare the female reproductive tract for pregnancy if fertilization occur
when does the ovarian cycle start?
The cycle starts at puberty and is normally interrupted only by pregnancy and is finally terminated by menopause
what are the steps of the development of ovarian follicle?
slide 24
what is the uterine/menstrual cycle?
Monthly series of cyclic changes that the uterine endometrium goes through each month in response to changing levels of ovarian hormones in the blood
what are the 3 consecutive phases of the menstrual cycle?
- menstrual phase
- proliferative phase
- secretory phase
what happens during the menstrual phase?
endometrium is shed from the uterus
what happens during the proliferative phase?
Endometrium is rebuilt becoming velvety, thick and well vascularised
what happens during the secretory phase?
Endometrium prepares for implantation of an embryo
what hormones are involved in the control of menstrual cycle?
- Gonadotropin-releasing hormone (GnRH) of hypothalamus
- Anterior pituitary gonadotropins
- Follicle stimulating hormone (FSH)
- Leutenising hormone (LH)
- Ovarian sex steroids
- Estrogens
- Progesterone