Reproductive Physiology

Question 1

Female Hormones

Answer 1

• GnRH = released by HYPOTHALMUS, acts on ANTERIOR PITUITARY
• GONATROPHINS = FSH + LH, released by ANTERIOR PITUITARY, acts on OVARIES○ FSH = Follicle Stimulating Hormone, stimulates FOLLICULAR RECRUITMENT + DEVELOPMENT + OESTROGEN PRODUCTION○ LH = Luteinising Hormone, maintains DOMINANT FOLLICLE, induces FOLLICULAR MATURATION & OVULATION + stimulates CORPUS LUTEUM function (endometrial growth)

• STEROID HORMONES = OESTROGEN, PROGESTERONE, TESTOSTERONE

○ OESTROGEN = from GRANULOSA CELLS

	○ Supports FEMALE SECONDARY SEXUAL CHARACTERISTICS & REPRODUCTIVE ORGANS
	○ -VE FEEDBACK CONTROL of LH & GnRH - except for LATE FOLLICULAR PHASE = +VE control of LH SURGE
	○ Stimulates PROLIFERATIVE ENDOMETRIUM
	○ -VE CONTROL of FSH

○ PROGESTERONE = from CORPUS LUTEUM - maintains SECRETORY ENDOMETRIUM, -VE FEEDBACK CONTROL of HPO

Question 2

Ovarian Cycle

Answer 2

Follicular Phase =

FSH stimulates multiple follicles to develop

Dominant follicle emerges

Increasing no. of granulosa cells (oestrogen-producing) in dominant follicle = -ve feedback control of anterior pituitary

When dominant follicle large enough = high enough [oestrogen] for +ve feedback control + LH surge

Egg released + corpus luteum left behind

Luteal Phase = under control of corpus luteum

Mainly releases progesterone -ve feedback control of gonadotropins + stimulates secretory endometrium

Question 3

Menstrual Cycle

Answer 3

Proliferative Phase = replaces endometrial lining after menstruation, under control of oestrogen

Secretory phase = prepares endometrium for implantation, under control of progesterone

Question 4

Oogenesis

Answer 4

Oogonia = mitosis starts in utero, forming primary oocytes + arrests in prophase 1 of meiosis 1

Menstrual cycle = some oocytes are hormone responsive during a cycle - 1 completes meiosis + releases polar body

If egg fertilised = meiosis 2 completed, releasing a polar body

Question 5

Systemic Effects of Oestrogen

Answer 5

CHO, fat, protein metabolism + fat distribution + mammary gland development
H2O & electrolyte balance
Blood clotting
Bone maturation & turnover

Question 6

Male Hormones

Answer 6

• GnRH = Gonadotrophin Releasing Hormone, released from HYPOTHALAMUS
• GONADOTROPHINS = FSH & LH, released from ANTERIOR PITUITARY○ FSH = stimulates SPERMATOGENESIS○ LH = stimulates productions of ANDROGENS (testosterone)

• TESTOSTERONE (TESTIS)

Question 7

Sperm Production

Answer 7

• SEMINIFEROUS TUBULE in testes contains:

○ GERM CELLS = produce SPERM
○ SERTOLI CELLS = SUPPORT SPERM-PRODUCING CELL, produce INHIBIN
○ INTERSTITIAL (LEYDIG) CELLS = produce TESTOSTERONE

• SPERMATOGENESIS = begins in PUBERTY, continues throughout life

○ Start w/ SPERMATOGONIUM (precursor of mature sperm/germ cell)
○ Undergoes MITOSIS + 2 ROUNDS of MEIOSIS = eventually forms 4 MATURE SPERM CELLS

Question 8

Testosterone Target Organs

Answer 8

Skin = hair growth, balding, sebum, production

Liver = serum protein synthesis

Brain = libido, mood

Muscle = strength & vol. increase

Kidney = EPO stimulation

Bone marrow = stem cell stimulation

Bone = accelerated linear growth + closure of epiphyses

Male sexual organs = spermatogenesis, prostate + penile growth & function

Question 9

Factors affecting oogenesis/spermatogenesis

Answer 9

Hormonal Control Problem = genetic, tumours, medications, functional

Production Site Problem = genetic, cancer treatment, vasectomy, surgery, trauma, infections