Reproduction

Question 1

How many oocytes are formed in embryonic development?
How many remain by birth?
How many are released into the fallopian tubes?

Answer 1

5 million form in embryonic development
0.5 million by birth
500 released into fallopian tubes

Question 2

Primordial oocyte features

Answer 2

Quiescent
Incomplete meiotic division
lined by squamous follicle cells on basal lamina

Question 3

Primary oocyte

Answer 3

Enlarged cuboidal follicle cells - form granulosa cells
Active and dividing
Striatum granulosum makes oestrogen
External stromal cells form thecal cells - Theca internal and theca externa
Theca interna makes androgens
Surrounded by zona pellucida

Question 4

Secondary follicle

Answer 4

Stratum granulosa thickens; forms corona radiata
Antrum appears
Cumulus oophorus - stalk suspends oocyte in antrum
Thecal cells - outermost

Question 5

Ovulation

Answer 5

Graafian follicle - mature follicle
Released due to LH surge –> follicle ruptures, SM contracts to squeeze egg out
Survives for 24hrs unfertilised

Question 6

Uterus histology

Answer 6

Perimetrium
Myometrium - 3 SM layers
Endometrium - ciliated and secretory simple columnar cells

Question 7

Cervix histology

Answer 7

Endocervix - Simple columnar epithelium, glandular

Ectocervix - Stratified squamous epithelium

Question 8

Cervical transformation zone histology

Answer 8

Simple squamous epithelium and cervical glandular epithelium
Reproductive years - junction at external os
Oestrogens - expansion of cervical stroma - eversion of columnar epithelium near external os and exposure to hostile vaginal environment - metaplasia into durable stratified squamous epithelium
Location of boundary changes over menstrual cycle
Increased risk of tumerous change

Question 9

Terminal duct lobular unit

Answer 9

Acini and intralobular collecting duct. Form functional metabolic unit

Question 10

Leydig cells

Answer 10

Produce testosterone. Between seminiferous tubules

Question 11

Sertoli cells

Answer 11

Support cells, in seminiferous tubulous. Fluid –> fluid flux

Question 12

Origin of epididymis and vas deferens

Answer 12

Wolffian (mesonephric) duct

Question 13

Clitoris histology

Answer 13

2 extra masses of cavernous tissue not present in males - bulbs of clitoris. Function unknown.

Question 14

Fibrocystic change

Answer 14

Benign
Common - almost considered physiological
Mid-late reproductive years
Variable dilation of ducts - cysts may form
Fibrosis, adenosis (acini proliferation), apocrine metaplasia (epithelial cells become pink and granular)
Lumps may result from fibrosis/cysts

Question 15

High pathogenic HPV types

Answer 15

16 and 18

Question 16

HPV oncogenic potential

Answer 16

E6/E7

Question 17

Role of E2 in HPV

Answer 17

E2 encodes transcription factor which suppresses E6/E7
If there is a break in HPV DNA as it integrates into the host genome - dysregulation of E6/7
E6 binds p53 - deactivation
E7 binds Rb
Results in uncontrolled proliferation of squamous epithelial cells

Question 18

Spermatogenesis

Answer 18

Spermatogonia (present in foetal life)
Mitosis - 2 daughter cells; 1 remains on outer edge, replacing germinal stem cells. Other moves towards lumen.
Daughter spermagonium divides by mitosis to again - 2 spermagonia
Spermagonia divide by mitosis - primary spermatocytes
First meitotic division - secondary spermatocytes
Secondary meitotic division - spermatids
Maturation - spermatozoa

Question 19

Production of sex hormones

Answer 19

Testes - testosterone, DHT (dihydrotestosterone)
Ovary - oestrogen, progesterone
Adrenal gland - Small amounts of sex steroids

Question 20

Regulation of sex hormones - male

Answer 20

Hypothalamus - GnRH
Anterior pituitary - FSH and LH
FSH acts on Sertoli cells - Inhibin (Keep FSH/testosterone levels in check via negative feedback to anterior pituitary), Spermatogenesis, androgen-binding protein (required to bind testosterone)
LH acts on leydig cells - Testosterone

Question 21

Nutrients in semen and source

Answer 21

Seminal vesicles - fructose and vitamin C
Prostate - citric acid
Epididymis - Carnitine

Question 22

Testosterone

Answer 22

Before birth - sexual differentiation; promotes testicular descent
Continuous secretion from puberty - sex drive, control of gonadotropin secretion, secondary sexual characteristics, protein anabolic effects, bone growth and closure of epiphysis, sebaceous gland secretion

Question 23

Oestrogen

Answer 23

Breast developmetn and body fat distribution

Question 24

Adrenal androgens

Answer 24

Hair growth and libido

Question 25

Oogenesis

Answer 25

Oogonium divide - primary oocytes Primary oocytes - arrest in first meiotic division After puberty - 1 primary oocyte reaches maturity and ovulated 1ce a month Primary oocyte complets first meiotic division prior to ovulation - secondary oocyte Secondary oocyte completes second meiotic division after fertilization - mature ovum

Question 26

Menstrual cycle - phases

Answer 26

Follicular/proliferation phase Ovulation Luteal/secretory phase

Question 27

Early-mid follicular phase

Answer 27

Hypothalamus secretes GnRH - FSH and LH from anterior pituitary LH - thecal cells to produce androgens FSH - granulosa cells to convert androgens in estrogen Oestrogen - negative feedback to hypothalamus and AP; positive feedback to granulosa cells

Question 28

Late follicular phase and ovulation

Answer 28

High oestrogen levels - negative feedback switches to positive feedback at the hypothalamus Granulosa cells produce inhibin - negative feedback on FSH Granulosa cells also produce small amount of progesterone (positive feedback on GnRH and LH)

Question 29

Early to mid luteal phase

Answer 29

Corpus luteum - high oestrogen, progesterone and inhibin Negative feedback at hypothalamus and pituitary Endometrium maintained Cervical mucus thick, sticky and viscous Increased basal body temperature

Question 30

Late luteal phase

Answer 30

Corpus luteum dies - decreased estrogen and progesterone Blood vessels constrict - decrease trophic support of endometrium - dies and sloughs off - menses Loss of negative feedback - Increased FSH and LH Cycle begins again

Question 31

Fertilisation

Answer 31

``` Ovulation Day 1 - fertilisation (sperm capacitation in vagina, swims upstream, reaches oocyte in fallopian tube, acrosomal reaction - digests zona pellucida and cell junctions, membranes fuse, sperm nucleus enters, cortical reaction blocks polyspermy, nuclear fusion - zygote produced, 2nd meiotic division completed producing polar body) Day 2-4 - Cell division Day 4-5 blastocyst reaches uterus Day 5-9 Blastocyst implants ```

Question 32

Critical weeks

Answer 32

``` Early pregnacy (weeks 1-2) - not susceptible to teratogens, susceptible to chromosomal abnormalities Embryonic period (weeks 3-8) - major organs develop. Susceptible to teratogens. Foetal period (week 9-40) - affected by genetic and environmental factors (multiple, pregnancy, maternal under nutrition, oxygenation, placental function, smoking, alcohol etc) ```