Reproduction Flashcards
Testes
- Located in scrotum in adult
- Formed near kidneys descend to scrotum ~28 wks of fetal life
- Guided by gubernaculum
- Undescended testes = cryptorchidism
- Infertility
Testis Function
- Gamete production (seminiferous tubules)
* Androgen secretion (interstitial tissue)
Epididymis
- Single, highly-coiled tube
- 2- 6 day passage
- Sperm maturation (gain motility, metabolic changes, cell membrane changes), storage (?) and transport
Vas deferens
- 35 cm long, thick muscular wall
- Sperm storage & transport
- Palpable
- Vasectomy – sterilization
Male accessory glands
Prostate
Seminal Vesicles
Bulbourethral glands
Prostate
Prostate • Single gland • ~30% of seminal fluid • Liquefying enzymes • Clinical significance – hypertrophy, cancer
Bulbourethral glands
• Paired glands
•
Seminal Vesicles
- Paired glands
- ~65% seminal fluid
- Alkaline
- Prostaglandins, clotting proteins & fructose
Erection: A Vascular Event
- Sexual arousal
- Nerves in penis release nitric oxide
- Vasodilation – increased blood flow to corpora cavernosa = erection
- Erectile dysfunction – ↑ with ageing due to ↑ vascular disease
Seminiferous tubule
- Germ cells - form sperm
- Sertoli cells – support, protection
Interstitial space
• Leydig cells - secrete testosterone (androgen)
Androgen
Androgen, also called androgenic hormone or testoid, is any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors
Temperature regulation of the testes
- Temperature in testes 2-3 oC lower than body temperature
- Sweat Glands
- Two sets of muscles (cremaster and tunica dartos) help regulate the temperature of the testes. The muscles contract, moving the testes closer to the body when the testes drop below normal temperature.
- The Pampiniform Plexus: The testicular artery entering scrotum from abdomen and the testicular vein entering the abdomen from scrotum lie in a tortuous plexus, formed by the testicular veins above the testes. Blood entering the scrotum from the abdomen is warmer than blood leaving the testes. Countercurrent heat exchange, from blood in the testicular artery to blood in the plexus formed by the testicular veins, decreases the temperature of blood entering the testes. By the same token, blood leaving the testes is warmed contact of the testicular veins with the testicular artery along the plexus.
Ovarian follicles
- House and nurture oocytes
* Secretes oestradiol & inhibin in first half of cycle under stimulation by gonadotrophins
Corpus luteum (CL)
- Formed from ruptured follicle (ie after ovulation)
- Secretes progesterone, oestradiol and inhibin
- In absence of pregnancy CL regresses after 10 -12 days –> scar tissue (corpus albicans)
Uterine tube (oviduct / Fallopian tube)
- Site of fertilization
- Ciliated and secretory (peg) cells
- Transports oocyte / embryo to uterus
- Early nourishment of embryo
Endometrium – menstrual cycle
- rich blood supply; highly glandular
- undergoes cyclical growth, loss and repair menstrual cycle
- influenced by cyclic changes in estradiol and progesterone
Menstrual cycle
- First day of menses (bleeding) = day 1 of cycle
- Length of cycle = interval between consecutive menses
- Average interval = 28 days
- Common variation = 21 to 35 days
- Reflects ovarian activity Luteal phase usually constant = 12-14 days, life of CL Follicular phase varies in length ∴ ovulation occurs ~12-14 days prior to next menses
- Variation has implications for failure of natural family planning methods
Cervix
- Fertile mucus (Oestrogen)
- Infertile mucus (Progesterone)
Regulate sperm transport
Vagina
Stratified Squamous Epithelium Epithelial cells accumulate glycogen > Converted to Lactic acid > Acidic pH > Inhibits pathogen growth
