Female reproductive system Flashcards
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)
Internal genitalia
Ovaries
Fallopian tubes
Uterus
Vagina
External genitalia
Mons pubis
Labia
Clitoris
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
Histology of the ovary
4 layers: - germinal epithelium - thin tunica albuginea - cortex - ovarian follicles + stromal supporting cells - medulla - vascular Neurovascular supply enters at hilum
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
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
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
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
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
Cervix
Projects into the vagina Forms fornixes (anterior and posterior) PAP smears - 12-13 year olds offered HPV vaccination
Vagina
8cm long
Mucosa arranged in folds (rugae)
Fibromuscular tube
Lined with stratified squamous epithelium
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
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
Lymphatic drainage of breasts
Majority via axillary lymph nodes
+ provides a pathway for metastasis of breast cancer +
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
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
Role of FSH in follicle development
Stimulates growth and development of follicles
Promotes secretion of oestrogen by ovaries
Promotes secretion of inhibin by ovaries
Ovulation
High concentration of LH increases collagenase activity
LH increases prostaglandin levels (causes local ovarian wall to contract)
Contractions extrude the oocyte
Role of LH in ovulaton
Pre-ovulatory surge of LH induces ovulation
Responsible for formation of corpus luteum (secretes progesterone)
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
Contraception - how does the pill work?
Combined pill = progestin plus oestrogen
- inhibition of GnRH which inhibits LH = thickens cervical mucus
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)
What is the pH of vaginal fluid and cervix ?
pH 4.3 = vaginal fluid
6-6.5 = cervix
