Female Reproductive Flashcards
Gross anatomy
Cervix= neck of uterus
Ovary covering and regions
Surface is covered by a single layer of epithelium (term germinal epithelium is a misnomer in the ovary).
3 Regions-
- Hilum - entry/exit point for vasculature and lymphatics
- Medulla- inner region
- Cortex- contains the gametes and support cells (stroma)
Produce steroid hormones and release eggs
Hypothalamic-Pituitary-Ovarian Axis
Stages of ovarian follicular development
Finite number that are present at birth
What does each mature follicle contain and what are the maturation stages?
Each mature follicle contains:
- an oocyte and its outer zona pellucdia
- support cells of the follicle (granulosa and theca cells)
- the fluid-filled antral cavity
Primordial follicle
Follicles develop during embryogenesis and the female has their full complement of oogonia by the second trimester of pregnancy.
Primary follicle
- Zona Pellucida develops at this stage. It is a glycoprotein coating that sperm must penetrate to get into oocyte during fertilisation
- Granulosa cell layers thicken
Secondary follicle
Can now see all 5 things in a mature follicle
Tertiary/Pre-ovulatory/Mature/Dominant/Graafian Follicle
- Bigger than secondary
- Fluid filled cavity enlarges to form the antrum
- Granulosa cells that separate the antrum and the oocyte form the cumulus-oocyte-complex (cumulus oophorus)
- Cumulus cells degenerate leaving the corona radiata
What is ovulation?
- Primary oocyte becomes secondary oocyte and you can see a polar body
- Follicle ruptures and fluid, oocyte and cumulus are released and coaxed into the Fallopian tube
- Follicle becomes the corpus luteum
Primary oocytes
All oocytes are present at birth within primordial follicles. All of the oocytes are paused in the meiosis I and called primary oocytes.
Secondary oocytes
Meiosis I is completed in the hours before ovulation and becomes secondary oocyte (1 polar body). Meiosis II starts but is paused. Meiosis II is only complete if fertilisation occurs (2 polar bodies)
Corpus luteum
Life cycle of the corpus luteum:
- Corpus haemorraghicum (red)
- Corpus luteum (yellow)
- Corpus albicans (white) small fibrous mass stops producing hormones and persists for a long time
Programmed to be steroidogenic for 14 days ± 2 and then undergoes leutolysis. If pregnant the CL remains until the placenta takes over steroidogenesis at week 13 of gestation
Corpus albicans
- White Body
- Oval mass of fibrous tissue
- Theca externa and fibroblasts produce collagen - replace lutein cells. Thus non-steroidogenic.
- Scar tissue which remains in the ovary in life.
Regions of fallopian tube
Layers of fallopian tube
Ampulla
- Site of fertilisation
- Highly folded epithelium allows for an increased surface areas
- Less smooth muscle (contraction is less important for transport)
1. Mucosa
2. Muscularis
Uterine cycle
Menses (Day 0-5)
- Shedding of endometrial lining
Proliferative Phase (Day 5-14)
- Growth of endometrial lining
Secretory Phase (Day 14-28)
Preparation for implantation
Menses
- Menses is the shedding of the functional layer of the endometrium.
- Onset of menses is often associated with muscle spasm and pain.
- Frequency 24-35 days
- Duration of flow 4-8 days
- Volume of blood loss 5-80 ml
Uterine body
Functional zone is shed during menses
Basalis layer not shed during menses
C = stratum compactum
S = Stratum spongiosum
B = Stratum basalis
My = Myometrium- Myometrial smooth muscle has three ill-defined layers. It is sensitive to hormones and undergoes hyper trophy (size) and hyperplasia (numbers) during pregnancy.
Uterine glands and arteries
Proliferative Phase Day 4-14
- Oestrogen promotes cell proliferation of basal layer to regenerate the endometrial lining.
- Stroma is compact
- Glands (G): short, straight, narrow, with little secretion
- M: mitotic divisions
Secretory Phase Day 14-28
- Progesterone inhibits further endometrial growth
- Induces differentiation of epithelium and stroma in preparation for decidualisation
- Early in the secretory phase subnuclear vacuoles appear (V) and then glands become corkscrewed and becomes full of secretion (SE)
Menstrual Phase Days 0-5
Progesterone withdrawal induces shedding of the functional layer of endometrium
B apoptotic bodies
F stratum functionalis
L leakage of blood
Cervix location and epithelium of ecto and endocervix
- Junction between cervix and uterine body is the internal os
- The lumen opens into the vaginal cavity at the external os where there is an important change in epithelium.
- Ectocervix- like vaginal squamous epithelium, it is stratified, squamous epithelium (non-keratinizing) & rich glycogen
- Endocervix- luminal portion, the canal is lined by a single layer of tall columnar mucus-secreting epithelium
Cervical stroma
The cervical stroma is composed of smooth muscle fibres and collagen
The ratio of collagen to smooth muscle may increase with age. Associated with increased risk during childbirth.
Transformation zone
- Puberty – ectropion, eversion of the endocervix exposed to acidic environment, becomes squamous
- The transformation zone is composed of new squamous epithelium in an area previously occupied by columnar epithelium.
- This process causes the openings of some of the crypts to become occluded thus forming the Nabothian follicles. These are really common and no reason to cause alarm.
- However, the constant change of epithelium include the development of abnormal epithelium which may lead to cancer
Vagina structure and function
7-9 cm in length but capable of distention and elongation
4 Layers-
- Stratified squamous epithelium
- Elastin rich submucosa
- Fibromuscular layer (ill-defined)
- Adventitia
Stratified squamous epithelium-
- Protects against acidic environment
- High glycogen content. Bacteria breaks down the glycogen + results in acidic pH. The pH restricts it to acid-loving commensals
- Deters invasion from pathogens eg. fungi Candida albicans - vaginal ‘thrush’
Elastin rich submucosa-
- Ridges shows that it can expand
- Important for intercourse and childbirth
