Reproductive System 1

Question 1

Purposes of the female reproductive system

Answer 1

• to ensure the survival of the human species
• to produce haploid ova
• to provide an environment for the fertilisation and development of ova
• to expel offspring from the body
• to provide the initial nutrition to the offspring by lactation

Question 2

Ovaries

Answer 2

• homologous to the testes
• 2-4cm in length
• maintained in position by mesovarium, ovarian ligament and suspensory ligament
• only location in female where meiosis occurs
• oocytes
  
  • immature eggs
• follicles
  
  • eggs + layer(s) of cells
• primary follicles
  
  • oocytes that have not completed the first stage of meiosis
  • present at birth
• secondary follicles
  
  • meiosis l complete
  • fluid-filled space (antrum)
• mature (Graafian) follicles
• ovulation

Question 3

What is meiosis?

Answer 3

• production of haploid cells from diploid cells
• diploid human cells contain 23 pairs of chromosomes
  
  • total = 46
• haploid human cells (sperm and ova) contain 23 chromosomes
  
  • total = 23

Question 4

Uterus

Answer 4

• is ~8cm long, 5cm wide, 2.5cm thick
  
  • much larger during pregnancy
• situated between the urinary bladder and the rectum
• divided into:
  
  • fundus
  • body
  • cervix
• uterus is covered externally by the peritoneum except the lower anterior part
• normally uterus is:
  
  • anteverted
  • anteflexed
• blood supply by uterine arteries

3 layers of the uterus

1. perimetrium (around the uterus, binds and keeps it together)
2. myometrium (muscle layer)
3. endometrium (lining of the uterus, goes through changes each month in non-pregnancy)

Question 5

Uterus

Endometrium

Answer 5

-very vascular, composed of simple columnar epithelium, uterine glands and stroma

Can be divided into:

• stratum functional is
• stratum basalis (permanent)

Question 6

Uterus

Uterine Tube

Answer 6

Open ended tube with finger like projections called fimbriae (aka fallopian tube, Wolffian duct)

Mucosa: ciliated columnar cells, secretory cells (infertility, usually due to some problem with the mucosa e.g.. scarring, STIs)
Muscularis: squeezes eggs along the fallopian tube
Serosa

Question 7

Female Cycles

Answer 7

Ovarian Cycle: monthly series of events associated with the maturation of an ovum
Menstrual cycle: series of changes in the endometrium of a non-pregnant female

Ovarian and Uterine (menstrual) cycles controlled by hormones
GnRH - from hypothalamus
FSH - from anterior pituitary
Estrogen, Progesterone, Inhibin - from ovary

Question 8

Ovarian Cycle

Answer 8

Day 1: GnRH from hypothalamus stimulates the release of:

• FSH and LH from pituitary gland
• FSH and LH stimulate the development of follicle
• follicle produces oestrogen which…
• inhibits GnRH release, decreasing FSH and LH release (negative feedback)
• follicle grows, more oestrogen released
• promotes GnRH release, increasing FSH and LH release (positive feedback)
• ovulation (day 14

Question 9

The oocyte travels along oviduct

Answer 9

Oocyte - enters fallopian tube (uterine tube / oviduct) at fimbria

• duct 4cm long
• usual site of fertilisation
• oocyte movement - beating of cilia on epithelium
• contractions of smooth muscle of wall
• takes days to reach uterus

Question 10

Uterine/Menstrual Cycle

Answer 10

• estrogen produced by follicle promotes proliferation of the endometrium
• corpus luteum secretes progesterone, thickening of lining, secretion of glycogen
• non-pregnancy: hormone levels drop - menses

Question 11

Menses

Answer 11

1. Corpus luteum degenerates
2. decreased E and P
3. endometrial blood vessels constricted
4. decreased O2 and nutrients to uterine lining
5. cells disintegrate
6. blood escapes from damaged capillaries
7. cellular debris and blood = menstrual fluid