W01: Male & Female Repro Phys Flashcards
Female Reproductive Organs
Ovaries: ovarian follicles which undergo oogenesis
Fallopian Tubes: Egg pickup
Uterus: Body - Implantation
Cervix - communicates with the vagina
Structure and function of ovary
Surface: connective tissue, simple cuboidal epithelium
Cortex: peripheralconnective tissue containing FOLLICLES; one oocyte surrounded by single layer of. cells
Medulla: central, vascular
Functions:
1) OOCYTE PRODUCTION = one mature egg per menstrual cycle
2) STEROID HORMONE PRODUCTION =
* estrogen develops female 2º sexual characters,
* progesterone prepares. endometrium for implantation
* 50% testosterone production before menopause
Process of oogenesis
- Foetal life: mitotic cell divison of oogonia = primordial germ follicles, process arrests until puberty sets in.
- Puberty: hormone secretion = meitoic process resumes = primordial follicle => primary and secondary follicle
- Fertilisation: second meitoic division after fertilisation
What is a primordial follicle
Primary oocyte arrested in first meitoic division surrounded by one layer of squamous pre granulosa cells
What is a primary follicle
Oocyte surrounded by zona and cuboidal granulosa cells
Secondary follicle
Increased oocyte diameter and multiple layer of granulosa cells, resumption of first meiotic division
Tertiary/Graffian Follicle
Follicular fluid secreted between the cells to coalesce to form antrum, completion of first meiotic division to form secondary oocyte and start of second meiotic division.
*start of antral phase
What follows the graffianfollicle
The preovulatory follice: the egg is surrounded by granulosa cells as well as antrum (pool of fluid)
Endocrine control of ovarian cycle; peaks and resulting effects
Gonadotropins acting on ovarian cycle:
1) FSH + LH increased = follicle developmnt
2) LH surge dt ESTROGEN peak = ovulation
= fertilised egg OR corpus luteum
Ovarian hormones acting on ovarian cycle:
1) Estrogen peaks followed by Luteal phase
2) Progesterone peaks = corpus luteum
3) E + P drop = -ve feedback stops = gonadotrophins released again
*meanwhile endometrium synchronously prepared
Endocrine control of menstrual cycle
- Endometrium thickens throughout the menstrual cycle dt ESTROGEN
- Mid-cycle: vascular changes in endometrium dt PROGESTERONE
How are ovarian and menstrual cycles linked
LH + FSH = ovarian cycle = Estrogen and Progesterone = Resulting changes in endometrium during the menstrual cycle
Endocrine Female Repro Axis
HYPOTH. => GnRH
ANT. PIT. => FSH + LH
OVARY => ESTROGEN + PROGESTERONE
* +VE feedback (day 12-14)
* -VE feedback (most of the cycle to prevent overproduction and ensure coordination)
=> UTERUS
Ovarian Cycle
1) FOLLICULAR PHASE
* FSH = follicle maturation = estrogen prod.
2) OVULATION
* LH surge = follicle ruptures and secondary oocyte released
3) LUTEAL PHASE
* Ruptured follicle forms a corpus luteum and secretes progesterone
4) MENSTRUATION
* degen. of corpus luteum = corpus albicans = new ovarian cycle begins
Describe the factors affecting oogenesis
a
Amenorrhoea
1º = Menarch / Never had
2º = absence of three or more periods in a row by someone who has had periods in the past
Causes of Amenorrhoea
- Disrupted regulating hormones
- Disrupted ovarian function
- Disrupted uterus or outflow tract
Disrupted regulating hormones = Amenorrhoea
- Disrupted regulating hormones
* low FSH, LH, high prolactin
* wt loss/gain; exertion, stress (functional)
* chronic conditions: DM, renal disease, TB
* intracranial SOLesion: prolactinoma, tumour, cysts
* Infection Trauma in brain
* Drugs: glucocorticoids, anabolid steroids, opiates suppress pituitary
* Kallmann’s syndrome
= hypogonadotropic hypogonadosm
Disrupted ovarian function = Amenorrhoea
Dt
* Turner’s Syndrome (46X), Fragile X
* Ageing = steep decline past 35yo
* AuIm Diseases
* RT or ChemoT
* Infection: TB, mumps oophoritis
= hypergonadotropic hypogonadism
Disrupted uterus or outflow tract = Amenorrhoea
Dt
* congenital = absent uterus, vagina, lack of mmullerian duct
- transverse vaginal septum
- androgen insens syndrome
- Iatrogenic
- Uterine adhesions or synechiae
- RT
Mgmt of Amenorrhoea
Lifestyle: stress, weight
Optimise control of chronic illness
Drugs: switch or halt
Prolactinoma - med tx
Sx tx = intracranial SOL, vaginal anomalies
Uterine adhesions = sx division hysteroscopic
*fertility preservation before RT and ChemoT
Describe the hormonal control of spermatogenesis
- GnRH (hypothalamus)
- FSH and LH (ant pit) = stimulate spermatogen. and testosterone secretion
FSH = Sertoli
LH = Leydig/Interstitial => Sertoli
• Leydig neg. inhibits Testosterone = neg feedback - Testosterone (testicles)
Describe the factors affecting spermatogenesis
1) MEDICAL
*PRETESTICULAR: hormonal
- functional: weight
- intracranial
- prolactinoma
- meds: opiates, ext. testosterone, steroids
- TESTICULAR: site of prod
- sx
- STI
- mumps orchitis
- trauma / torsion
- RT, chemoT
- Klinefelters
2) LIFESTYLE
- reversible: environmental exposures
- obesity
3) COMBINATION
List the major actions of sex steroids in the male
LH = LEYDIG = TESTOSTERONE = SPERMATOGENESIS
FSH = SERTOLI = SPERMATOGENESIS
INHIBIN (SERTOLI) = NEG FEEDBACK
Testes Structure and function
1) sperm prod (64 day cycle)
2) testosterone prod (controls spermatogenesis + sexual characs)
*Sperm created in the testis => remain and mature in epididymis => vas deferns => urethra
+ seminal fluid
- SEMINIFEROUS TUBULES (site of sperm prod) segmented by TUNICA ALBUGINEA
=> RETE TESTIS = site of merging of tubules => stored at head of epididymis => body and then tail - Within the seminiferous tubules:
GERM CELLS = PRODUCE SPERM
SERTOLI CELLS = support producing-cells, produce inhibin
INTERSTITIAL CELLS = produce testosterone
What cells are responsible for testosterone production?
Leydig / Interstitial Cells produce testosterone under the influence of LH (ant pit.)
Describe the process of sperm production
1) SPERMATOCYTOGENESIS
- Clonal expansion via mitosis; SPERMATOGONIUM to 1º SPERMATOCYTE
- Followed by Maturation via meiosis; first division 1º to 2º spermatocyte produces 2 haploid cells
- second meitoic division produces SPERMATID
2) SPERMIOGENESIS
- Differentiation into mature functional sperm cells
Oligospermia
fewer than 15 million sperm per millilitre of semen.
Azoospermia:
Lack of sperm cells in semen. About 2% of the total male population is affected by it. It may be due to either a lack of sperm cell production in the testicles or to an obstruction in the seminal conducts that prevents them from being ejaculated.
Polizoospermia
It takes place when there are more than 200 million spermatozoids per cc. It may be a cause of infertility since such a high concentration can difficult their movement. Polizoospermia is usually associated to a decrease in the volume of ejaculated matter.
