Lecture notes
Reproductive (BS)
- Module
- Body Systems
- Institution
- University Of Leeds (UoL)
Body Systems STRAND 5 - Reproductive medicine and anatomy
[Show more]
Content preview
BODY SYSTEMSREPRODUCTIVE
,Medic_Summaries (Body Systems)
Reproductive Strand
Menstrual cycle:
- Purpose:
- Generate oocyte
- Facilitate fertilisation
- Optimise endometrium for implantation
- Protect developing embryo
- Begins at MENARCHE
- Ends at MENOPAUSE
Endocrine control:
Gonadotrophin releasing hormone (GnRH):
- Decapeptide
- Secreted by mid basal hypothalamic neurones
- Hourly pulses
- Transported to pituitary via hypophyseal portal blood system
- Secretion affected by:
- Bereavement
- Anxiety
- Time zone
- Day/night duty
- Exercise
- Weight loss/gain
Anterior pituitary:
- Basophils secretes follicle stimulating hormone (FSH) and luteinising hormone (LH)
- FSH stimulates follicular activity, thus promoting estradiol (E2; oestrogen) production
- LH triggers release of egg from dominant follicle, promoting development of corpus luteum
and production of progesterone
Negative/positive feedback:
- GnRH, LH and FSH production inhibited by rising E2 levels
- Near midcycle, high levels of E2 lead to surge in LH release, which triggers ovulation
2 Adapted from Lectures at the University of Leeds Medical School
, Medic_Summaries (Body Systems)
Ovaries (primordial follicles):
- In foetus at 6 months (2,000,000)
- At birth (750,000)
- At puberty (400,000)
- Ca. 450 follicles develop and produce an egg (remainder degenerate)
- No new follicles produced
- Progression:
- Primordial follicle
- Primary/preantral follicle
- Secondary/antral follicle
- Preovulatory follicle
- Ovulation
Follicular development:
- Proliferation of granulosa cells; antrum develops (fluid)
- Gap junctions and cytoplasmic processes between oocyte and granulosa cells allows
communication and passage of low molecular weight materials (nutrients)
- Proliferation of thecal cells (external to granulosa cells):
- Theca interna: glandular and highly vascularised
- Theca externa: fibrous capsule
- Interaction between follicular cell types critical:
- Androgens secreted by theca interna cells
- Convert to estradiol 17-beta in granulosa cells
Post-ovulation:
- Empty Graafian follicle (granulosa cells undergo luteinisation to corpus luteum)
- If no fertilisation, corpus luteum degenerates/fibroses to become corpus albicans
Endometrium (uterus lining):
- Proliferative phase:
- Endometrium thickens
- Estradiol dominant
- Increased stromal cells, glands and blood vessels
- Endometrium is 2-3mm thick
- Secretory phase:
- Progesterone dominant
- Increased secretion, lipids and glycogen, and blood supply
- Endometrium 4-6mm thick
- Optimal conditions for implantation of fertilised egg
- Menstrual phase:
- Vasodilation (vasospasm of blood vessels - PGF2-alpha)
- Necrotic outer layers of endometrium separate from uterus
- Separated tissue and blood initiate uterine contractions (expel contents)
Cervix:
- Mucus production from columnar glands
- Stringy/runny midcycle (spinnbarkeit; facilitates sperm access at ovulation)
- Tenacious/inelastic in luteal phase (prevents microbial ingress to protect embryo; critical to
pregnancy (mucus ‘plug’))
Timing of ovulation:
3 Adapted from Lectures at the University of Leeds Medical School
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller medicsummaries. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £5.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
84866 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now