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