Reproductive System 2 Flashcards
Reproductive Hormones
- oxytocin
- prolactin
- human chorionic somatomammotropin
- human chronic gonadotropin
- relaxin
- testosterone
Contraception - pill
Combined oral contraception pill (COCP)
Minute doses of oestrogen’s and progesterone
‘Tricks’ the hypothalamic-pituitary axis and makes it appear that woman is pregnant
Negative feedback
Menopause
- cessation of ovulation and mestruation
- after approx. 450 ovarian cycles (46-54 years)
- fluctuating and decreasing levels of hormones (FSH, LH and oestrogen)
- decreased responsiveness of ovaries to FSH and LH
- failure of follicles to mature
- decreased estrogen concentration
- regression of secondary sexual characters
- breast size decrease
- reproductive organ size decrease
- increased concentration of gonadotropins (GnRH)
- hot flush symptoms
Estrogen
- responsible for secondary sexual characteristics
- for growth of breasts and uterus
- influences the production of cervical mucus and the structure of vaginal epithelium
- this encourages growth of bacteria (lactobacilli ferments stored glycogen) which are responsible for the acidity of the vaginal fluid (pH around 4-4.5)
- causes the proliferation of the uterine endometrium
- inhibits FSH
- encourages fluid retention (stimulates sodium reuptake in the kidneys)
Progesterone
- only act on tissues which have previously been affected by estrogen
- causes secretory changes in the lining of the uterus
- causes the body temp to rise by 0.5 degrees after ovulation
Male reproductive system
Purpose
To produce and deliver spermatozoa into the uterus and fallopian tubes
Function of:
Testes, Epididymis and Vas Deferens
Testes: endocrine function (steroid hormone), produce sperm
Epididymis: maturation of sperm (18hrs -10 days), stores sperm
Vas Deferens: stores sperm, conduit for sperm delivery
Testes in the scrotum
Testes lie within the scrotum - skin sac
- allows temperature regulation below normal body temperature
- viable sperm - produced at 3 degrees celsius less than body temperature
Sustentacular (sertoli) cells
- embedded between developing sperm cells
- joined to one another by tight junctions to form blood testis barrier that prevents immune response
- support and protect developing spermatogenic cells
- nourish spermatocytes, spermatids and spermatozoa
- phagocytosis (immune function)
- control movements of spermatogenic cells and the release of spermatozoa into the lumen
- secrete hormone ‘inhibin’ that regulates sperm production
Interstitial cells of Leydig
- are in between seminiferous tubules
- secrete testosterone
Seminal vesicle
- 60% of the volume of semen
- alkaline (balance out the acidity of the vagina, helps the sperm to survive)
- viscous fluid
- prostaglandins (causes cervix to open)
- contains fructose (sugar that powers sperm, as they have no energy reserves)
Prostate gland
- 10-30% of the volume of semen
- size of chestnut
- secretes thin, milky fluid
- contributes to sperm motility and viability
Semen
- is a thick, whitish fluid
- 2.5-5ml/ejaculation
- 50-150 million sperm/mL semen
- contains sperm, seminal plasma from prostate and seminal vesicles
- pH = 7.2 - 7.6 (slightly alkaline)
Factors influencing sperm formation
- malnutrition
- alcoholism
- drugs, radiation, high temperature
- also testicular cancer
Testosterone
- synthesized from cholesterol in Leydig cells
- controls development, growth and maintenance of male sex organs
- stimulates bone growth
- protein anabolism
- sexual behaviour
- final maturation of sperm
- stimulates descent of testes
- development of male secondary sex characteristics
- inhibin: inhibits secretion of FSH
- produced by sustentacular cells (sertoli cells)
-testosterone levels in females too, responsible for sexual drive
