Reproductive - femes Flashcards
What is the Mean duration of the menstrual cycle
28 days
Range 21-35
What is the average duration of menses?
3-8 days
When does ovulation occur?
day 14
What are the phases of the menstrual cycle? (4)
Proliferative(follicular) phase, ovulation and secretory(luteal) phase and menstruation
Which part of the hypothalamus produces GnRH
Arcuate nucleus
What is the Hypothalmic/Pituitary/Gonadal axis?
Hypothalamus responds to low oestrogen levels by releasing GnRH
GnRH stimulates the pituitary gland to secrete FSH and LH
FSH and LH cause cells to release steroids.
High inhibin (from FSH) and oestrogen levels cause the hypo. to stop producing GnRH
The ovary is attached to the pelvic wall
T
What two structures form the ovary?
Outer cortex and inner medulla
Which part of the ovary contains the follicles?
Cortex
Describe the structure of the uterus
Fibro muscular organ
Contains the body of the uterus and the cervix
Endometrium - basal layer and superficial layer
Which hormone results in thickening of the endometrium in the uterus?
Endometrium thickens in response to estrogen
What causes the endometrium in the uterus to slough off?
Lack of hCG and progesterone
Which type of cell does FSH affect? What does it stimulate this cell to release?
Granulosa cell, estrogen from androgen precursor, Inhibin
Which type of cell does LH affect? What does it stimulate this cell to release?
Theca cell, androgen
There are three types of GnRH hormone, which one is responsible for the reproductive function?
GnRH 1
What is the half life of GnRH?
Half life is 2- 4 minutes
What is the half life of FSH?
Half life of several hours
Which enzyme do androgens react with in granulosa cells to form estrogen?
Aromatase
What does FH do?
granulosa cell growth and activates aromatase activity
Which hormone induces the uptake of cholesterol in the theca cells?
LH
In the ovaries, what is cholesterol ultimately converted to? What are the steps in this conversion? (4 inc cholesterol)
Cholesterol
Pregnenolone
Androstendione
Estradiol
What are the main actions of inhibin?
2
- -ve feed back on pituitary FSH secreation
2. Locally enhances LH-induced androstenedione production
What is the main action of activin?
Stimulates FSH induced estrogen production
Where are inhibin and activin BOTH found?
follicular fluid
Where do the theca and granulosa cells originate from?
Ovaries/ grow from follicles
What happens in the follicular stage of the menstrual cycle?(5)
- Begins when estrogen levels are low
- Anterior pituitary secretes FSH and LH stimulation follicle to develop
- A leading follicle develops
- Granulosa cells around egg enlarge, releasing estrogen
- This causes this uterine lining to thicken
What happens in the ovulation stage of the menstrual cycle?(5)
- Happens at the peak of follicular growth in response to LH surge
- Follicle continues to grow
- After the LH peak, the oocyte is released
- Several proteolytic enzymes and prostaglandins are activated- digestion of the follicle wall collagen (leaving granulosa cells in ovary)
- Follicle ruptures, releasing ova into the Fallopian tubes
What happens in the luteal stage of the menstrual cycle?(2)
- Remaining granulosa cells in ovary develop in corpus luteum
- Corpus luteum produces progesterone
What happens in the menstruation stage of the menstrual cycle?(3)
- If no embryo, the corpus luteum begins to disintegrate (If pregnant, embryo will release hormones to preserve corpus luteum)
- Progesterone levels drop, uterine lining detaches, menstruation can begin
- Tissue, blood, unfertilized egg all discharged
Which hormones cause negative feedback (down regulation of FSH and GnRH synthesis)? (3)
Inhibin
Estradiol
Progesterone
Oligomenorrhea:
reduction in frequency of periods to less than 9/year
Primary amenorrhea:
failure of menarche by the age of 16 years
Secondary amenorrhea:
cessation of periods for >6 months in an individual who has previously menstruated
