oogenesis, the female tract and endocrine control (2)

Question 1

uterus

Answer 1

• muscular organ
• 7.5cm long and pear shape
• luminal volume ~10mls
• pregnant uterus contains ~5L of baby, amniotic fluid and placenta
• growth partially under the control of estrogen
• growth due to stretching of existing cells rather than proliferation

Question 2

uterus position

Answer 2

normally anteverted
- top faces forwards

25% of women have a retroverted uterus (no effect on pregnancy)

Question 3

uterus structure

Answer 3

top = fundus
bottom = cervix (projects into vagina)

3 main layers:

• 1. serosa (perimetrium)
• 2. muscular myometrium
• 3. inner endometrium

Question 4

myometrium

Answer 4

• 90% of uterine tissue
• allows expulsion of fetus
• no effected by menstrual cycle
• 10mm thick

Question 5

structures within endometrium and changes during menstruation

Answer 5

basilar layer = retained during menstruation

functional layer = lost during menstruation

uterine glands = lost during menstruation

simple columnar epithelium = lost during menstruation

Question 6

decidua

Answer 6

name given to endometrium during pregnancy

tissue which dissociates from the uterus when the placenta is delivered

where the human embryo implants

endometrium become decidualized during each menstrual cycle

Question 7

phases of uterine cycle

Answer 7

menses

proliferative phase

secretory phase

Question 8

phases of the ovarian cycle

Answer 8

follicular phase

luteal phase

Question 9

decidual reaction

Answer 9

fibroblasts in the stroma of the uterus (endometrium) become oedematous and lay down glycogen for the embryo to eat

cells change from long spindle cells to large polygonal cells

occurs spontaneously each menstrual cycle

Question 10

uterine blood supply

Answer 10

uterine artery –> radial artery –> arcuate arteries –> radial arteries –> spiral artery (only arteries in endometrium = gets shred)

Question 11

blood supply during pregnancy

Answer 11

mums blood gets to the placenta via the spiral arteries

Question 12

blood supply and menstruation

Answer 12

the spiral artery terminal segments are lost along with the rest of the functionalis layer of the endometrium

• to prevent excessive blood loss these arteries undergo spasm

Question 13

relationship between cycle length and age

Answer 13

average cycle length decreases as age increases

• cycle lenghts shorten from 30 days in females aged 18 to 28 days in women aged 42 (AVERAGE)

Question 14

follicular vs luteal phase

Answer 14

follicular/proliferative phase is longer and more variable in length than the luteal/secretory phase

Question 15

importance in dating the endometrium

Answer 15

implantation occurs around 7 days post ovulation therefore can assist fertility

• commonly done through ultrasound (measuring thickness) or biopsy

Question 16

features of early luteal

Answer 16

• tortuous glands
• basal vaculotation
• glandular secretions

Question 17

estrogen stimulates

Answer 17

• epithelial and stromal cell proliferation
• stromal odema
• glandular secretions (serous)
• synthesis of intracellular progesterone receptors (estrogen priming)
• myometrial activity

Question 18

progesterone stimulates

Answer 18

• glandular secretions in luteal phase (against an estrogen background)
• stromal cell differentiation

Question 19

progesterone inhibits

Answer 19

myometrial activity (smooth muscle relaxant)

Question 20

ectopic implantation

Answer 20

• can occur anywhere in the abdominal cavity

- most common inside the fallopian tubes

Question 21

endometriosis

Answer 21

endometrial tissue outside of the uterus often on the ovaries

• associated with infertility
• causes chronic pain

Question 22

zones of the cervix and epithelium

Answer 22

endocervix = columnar

transformation = squamous (HPV infects here and can lead to cervical cancer)

ectocervix = stratified squamous