Phys: Female Reproduction

Question 1

describe oogenesis

Answer 1

• mitosis to form primary oocyte
• during fetal development, meiosis I begins
• after puberty, primary oocytes complete meiosis I, produce a sec. oocyte and first polar body (N + N - haploid, chromosomes no longer paired but same genetic material)
• sec. oocyte begins meiosis II
• sec. oocyte and first polar body ovulated
• after fertilisation, meiosis II resumes
• oocyte splits into ovum and second polar body

Question 2

Which hormone stimulates follicular development?

Answer 2

FSH

Question 3

What days of the ovarian cycle make up the follicular phase?

Answer 3

• Day 1 - 14

- Massively varied in different woman (could be as short as 7 days)

Question 4

Which hormone triggers ovulation?

Answer 4

LH

Question 5

Which days of the ovarian cycle make up the luteal phase?

Answer 5

Day 14 - 28

- not as varied

Question 6

What happens in the luteal phase?

Answer 6

• sec. oocyte released and corpus luteum is formed
• CL secretes progesterone (and oestrogen) which is essential for maintenance of uterus in 2nd half of menstrual cycle
• breaks down if fertilisation does not occur which causes menses
• maintained if fertilisation occurs until placenta forms

Question 7

Describe the hormonal control of the ovarian cycle.

Answer 7

• Hypothalamus - GRH - stimulates FSH and LH in ant. pituitary
• FSH stimulates granulosa cells to produce oestrogens (-ve feedback on FSH and GRH) and androgens FOLLICULAR PHASE
• Low oestrogen -ve feedback on LH, until around day 10 when oestrogen conc. is high enough to +ve feedback - LH surge - OVULATION occurs
• LH causes ovulation and causes theca cells to produce androgens
• Corpus luteum secretes progesterone and oestrogen (-ve feedback on LH and GRH) LUTEAL PHASE

Question 8

What are the phases of the uterine cycle?

Answer 8

• Menstruation (day 0-4)
  Stratum functionalis of endometrium shed
• proliferative phase (day 4 - 14)
  Cell proliferation and glandular development (test tube) in stratum functionalis to thicken wall
  High amount of oestrogens
• secretory phase (14-28)
  Wall thickness same but cells continue to divide
  Gland become tortuous and coiled (sawtooth) and secrete sticky, glycogen-rich mucus for fertilised egg to stick
  High amount of progesterone

Question 9

What are the secondary sexual characteristics in females?

Answer 9

• fat deposition (breasts, thighs)
• breast development (oestrogen - duct development + maintenance, progesterone - secretory lobules)
• wide hips
• maintenance of voice
• “flat top” pattern of pubic hair
• uterine muscles - gap junctions between cells so they are more electrically and mechanically connected
• behavioural characteristics