Female reproductive system Flashcards Preview

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Flashcards in Female reproductive system Deck (28):
1

Functions

Production of female gametes (ova)
Production of oestrogen, progesterone, LH, FSH, inhibin, oxytocin
Provides the site for nourishment and development of the embryo (uterus)

2

Internal genitalia

Ovaries
Fallopian tubes
Uterus
Vagina

3

External genitalia

Mons pubis
Labia
Clitoris

4

Ovaries

4x2x1cm
Source of germ cells: develop into ovum
Endocrine organ as secretes hormones oestrogen, progesterone and inhibin
Lies on surface of broad ligament
Ovarian ligaments:
> ligament of ovary
> uterus
> broad ligament
> suspensory ligament

5

Histology of the ovary

4 layers:
- germinal epithelium
- thin tunica albuginea
- cortex - ovarian follicles + stromal supporting cells
- medulla - vascular
Neurovascular supply enters at hilum

6

Oogenesis

A female is born will all her ova in her ovaries (6 million), only release 300 in lifetime
Process by which ova are produced;
> mitosis (diploid)
> meiosis (haploid)
Mitosis completed during foetal life
Oocytes start meiosis 1 in foetal life but don't complete it until after puberty
Released oocyte starts meiosis 11
Meiosis 11 only complete if fertilisation occurs

7

Fallopian tubes

Also called uterine tube (10cm in length)
Has 4 parts:
- infundibulum
- ampulla
- isthmus
- intramural segment
Ciliated fimbriae (finger like projections) - move to produce currents
Functions:
- convey oocyte from peritoneal cavity to uterus
- site of fertilisation (usually ampulla)
Cilia = peristalsis
Fertilisation can take up to 24 hours after ovulation
3-4 days for zygote to travel through fallopian tube

8

Uterus

Shaped like an inverted pear
7.5cmx5cmx2.5cm
Flattened anteroposteriorly
Lies between bladder and rectum
Tilted and bent anteriorly
Lies superior to the bladder
Held in place by a number of ligaments
> fundus
> body
> cervix

9

What are the 3 layers of the uterus?

Perimetrium:
- covering of peritoneum
Myometrium:
- smooth muscle wall
- three poorly defined layers
Endometrium:
- mucous membrane
- undergoes extensive changes during menstrual cycle
functional zone = structure changes dramatically, sheds monthly
basal zone = not shed, provides cellular reserve for re-growth of functional layer

10

Menstrual cycle: hormonal changes

Menstrual, days 1-5: spiral arteries constrict, functional layer sloughed off
Proliferative, days 6-14: oestrogen; build up of tissue
and simple glands formed
Secretory (after ovulation), days 15-28: progesterone; glands enlarge and spiral arteries coil

11

Cervix

Projects into the vagina
Forms fornixes (anterior and posterior)
PAP smears - 12-13 year olds offered HPV vaccination

12

Vagina

8cm long
Mucosa arranged in folds (rugae)
Fibromuscular tube
Lined with stratified squamous epithelium

13

Pelvic floor (diaphragm)

Pelvic floor muscles hold all pelvic and abdominal organs in place
Levator ani must relax to allow urination and defecation and important for maintaining urinal and faecal continence

14

Mammary glands

Consist of:
1. adipose tissue
2. glandular tissue
3. fibrous tissue
Milk produced in glandular tissue and secreted into ducts
These ducts drain into lactiferous ducts which open out on the nipple
Glandular tissue increases during tissue in preparation for lactation
Development of acini is stimulated by progesterone during pregnancy
Anterior pituitary release prolactin
Acini cells synthesise milk proteins and lipids
Posterior pituitary releases oxytocin (in response to suckling stimulus)
Oxytocin stimulates ejection by mammary glands

15

Lymphatic drainage of breasts

Majority via axillary lymph nodes
+ provides a pathway for metastasis of breast cancer +

16

What processed do hormones control?

Menstrual cycle
Ovulation
Preparation of uterus for implantation
GnRH is released from hypothalamus, causing LS and FSH to be released from anterior pituitary.
This causes the ovaries to release oestrogen, progesterone and inhibin

17

Follicle development

Follicle = ovum + surrounding follicular cells
Only one follicle matures to become a tertiary follicle
Granulosa cells secrete follicular fluid
Protrudes from surface of ovary

18

Role of FSH in follicle development

Stimulates growth and development of follicles
Promotes secretion of oestrogen by ovaries
Promotes secretion of inhibin by ovaries

19

Ovulation

High concentration of LH increases collagenase activity
LH increases prostaglandin levels (causes local ovarian wall to contract)
Contractions extrude the oocyte

20

Role of LH in ovulaton

Pre-ovulatory surge of LH induces ovulation
Responsible for formation of corpus luteum (secretes progesterone)

21

Corpus luteum

No fertilisation occurs:
- corpus luteum degenerates 12 days post ovulation
- progesterone and oestrogen levels fall
- fibroblasts invade corpus luteum and form scar tissue (corpus albicans)
- disintegration of corpus luteum marks the end of ovarian cycle
Fertilisation occurs:
- future placental tissue secrete a hormone ( human chorionic gonadotrophin - hCG)
- maintains corpus luteum in a functional state
- after 2 months, placenta produces enough oestrogen and progesterone to maintain pregnancy

22

Contraception - how does the pill work?

Combined pill = progestin plus oestrogen
- inhibition of GnRH which inhibits LH = thickens cervical mucus

23

Menopause

Occurs 45-55yrs
Physical and emotional symproms eg. hot flushes, night sweats, irritability
Perimenopausal
Age linked to mother
1. Decrease in oestrogen = ovulation ceases = cessation of menstruation
Hormone Replacement Therapy (HRT)

24

What is the pH of vaginal fluid and cervix ?

pH 4.3 = vaginal fluid
6-6.5 = cervix

25

Fertilisation

1.Heads of spermatozoa bind to zona pellucida
2. Acrosomal reaction (release of enzymes in acrosome)
3. Mechanical propulsion and digestion of a pathway
4. Binds to plasma membrane of egg, and contents of spermatozoon enter the egg
5. Polyspermy is prevented
6. Egg completes meiosis 11
7. Membrane forms around the females chromosomal material
8. Female and male membranes break down and chromosomes intermingle and become organised
9. Fertilised egg = zygote
Day 5 = 107 cells known as a blastocyst

26

Implantation

8 days post-fertilisation, embryo attaches to lining of endometrium
Embeds within stroma
50% of fertilised eggs do not develop to maturity
Failure to implant is a problem in IVF

27

What is an ectopic pregnancy?

Where the foetus develops outside the womb, usually in the fallopian tubes

28

Describe the stages of labour

1st stage = dilation (6-24 hours)
- contractions start (in upper part of uterus, moving down to vagina)
- cervix softens and dilates
- amnion ruptures
2nd stage = expulsion (20 mins-2 hours)
- from full dilation to delivery (oxytocin secreted in response to stretch of cervix - positive feedback)
3rd stage = placental stage
- delivery of placenta within 15 mins of birth
- requires continued strong uterine contractions causing it to detach from uterine wall