5. Menstrual Cycle and Menstrual Disorders Flashcards
Relationships between ovarian and uterine changes during the MC
Slide 5
Phases of endometrial cycle?
Menstrual, proliferative, secretory
Uterine changes during 1. menstrual phase of MC?
Day 1= First day of menstrual flow
Duration =3-5days
Epithelial lining of uterus (endometrium) degenerates
Part of ovarian follicular phase
Uterine changes during 2. proliferative phase of MC?
Menstrual flow ceases
Under influence of oestrogen, the endometrium thickens. The growth of the underlying smooth muscle (myometrium) also occurs.
Synthesis of receptors for progesterone in endometrium cells
Lasts for about 10days until ovulation
Still apart of ovarian follicular phase
Features of proliferative phase of MC
- Repair of lining epithelium acer menstruation
- Proliferation and thickening of stroma
- Simple test tube shaped glands
- Induction of synthesis of intracellular receptors for progesterone (i.e. it primes the uterus for later progesterone secre:on)
- Contractility and excitability of the myometrium increases
The prolifera:ve phase of the uterine cycle is simultaneous with the ______ ____ of the ovarian cycle
Is dominated by ______
The prolifera:ve phase of the uterine cycle is simultaneous with the follicular phase of the ovarian cycle
Is dominated by estradiol 17β
Uterine changes during 3. secretory phase of MC?
Begins soon after ovulatiojn
Endometrium increases secretory activity under influence of progesterone. Acting on oestrogen primed tissue
Endometrial glands changes:
- Become coiled and fill with glycogen
- Blood vessels become more numerous
- Enzymes accumulare in glands and connective tissue
Coincides with ovarian luteal phase
The secretory phase of the uterine cycle is simultaneous with the _____ phase of ovarian cycle
Dominated by _________
The secretory phase of the uterine cycle is simultaneous with the luteal phase of ovarian cycle
Dominated by Progesterone
Features of secretory phase?
• Proliferation/thickening of stroma
• Spiral arteries develop alongside complex,
hacksaw shaped glands
• Secretion in the glands is rich in glycoprotein sugars and amino acids
• Enlargement of myometrial cells but depressed overall excitability
What are the events to the endometrium that occur during the ischaemic phase? (i.e. loss of steroid support from follicle)
Between secretory and menstrual phases.
Constriction of spiral arteries
Ischemia and collapse of endometrium
Separation of basal and functional layers
Functional layer is shed as menstrual bleeding
Increase in neutrophils
Volume of menstruation
30-80mls
What is dysmenorrhoea?
Painful contraction during menstruation
the bleeding is due to…
Endogenous fibrinolytic activity
Menstrual cycle major events days 1-5
Oestrogen and progesterone levels low because the previous CL is regressing
Therefore:
-Endometrial lining sloughs
-Secretion of FSH and LH is released from inhibition and their plasma cones increase
–> Several growing follicles are stimulated to mature
Menstrual cycle major events day 7
A single follicle becomes dominant
Menstrual cycle major events days 7-12
Plasma oestrogen increases because of secretion by the dominant follicle
–>Endometrium is stimulated to proliferate
LH and FSH decrease due to oestrogen and inhibin negative feedback
–> Degeneration of non-dominant follicles occurs
Menstrual cycle major events days 12-13
LH surge by increasing plasma oestrogen
- -> Oocyte is induced to complete its first meiotic division and undergo cytoplasmic maturation
- ->Follicle is stimulates to secrete digestive enzymes and prostaglandins
Menstrual cycle major events day 14
Ovulation is mediated by follicular enzymes and prostaglandins
Menstrual cycle major events days 15-25
CL forms and under influence of LH (Levels low but adequate) secretes oestrogen and progesterone
–> Secretory endometrium develops
–>Secretion of FSH and LH is inhibited, lowering their plasma concentration
Hence no new follicles develop
Menstrual cycle major events days 25-28
CL degenerates (if implantation of the conceptus does not occur) --> Plasma conc of oestrogen and progesterone decrease Results in endometrium sloughs at day 28 and a new cycle begins
Menstrual disorder terminology: • Meno? • Oligomenorrhoea ? • Metrorrhagia? • Dysmenorrhoea? • Polymenorrhoea? • Amenorrhoea?
- Meno – menstruation
- Oligomenorrhoea - infrequent light periods
- Metrorrhagia - irregular bleeding
- Dysmenorrhoea - painful periods
- Polymenorrhoea – frequent periods
- Amenorrhoea - no periods
Main cause of dysmenorrhoea?
Oveproduction of prostaglandins produced by endometrium in response to decrease in plasma oestrogen and progesterone
Leads to excessive uterine contraction
Why are there associated systemic effects with cramps?
Prostaglandins can affect smooth muscle elsewhere and may account form some of the systemic symptoms that sometimes accompany cramps eg nausea, vomiting, headache.
What is PMS?
Prementrual syndrome
