Reproductive System Flashcards
What does gonadotropin-releasing hormone stimulate the anterior pituitary to produce?
FSH and LH
What cells around the follicles in the ovary produce oestrogen?
Theca and granulosa cells
What effect does oestrogen have on hypothalamus and anterior pituitary?
Supress the release of GnRH from hypothalamus and LH+FSH from anterior pituitary
What is the most prevalent and active version of oestrogen?
17-beta oestradiol
What changes does the action of oestrogen on its receptors stimulate in the body?
Breast tissue development, development of female sex organs in puberty, blood vessel development in uterus, development of endometrium
What are oestrogen and progesterone?
Steroid sex hormones
where is progesterone produced normally and during pregancy?
Corpus luteum after ovulation normally
In pregnancy progesterone is produced from placenta after 10 weeks gestation
What does progesterone cause?
Thickening of cervical mucus
Thickens and maintains the endometrium
Increase body temperature
Why is it that overweight girls tend to undergo puberty earlier?
Aromatase enzyme is found in adipose tissue. The more adipose tissue the more aromatase which is important in creation of oestrogen
How is GnRH produced in puberty?
Initially during sleep, then throughout the day in later stages
What are the four stages of development a follicle undergoes in the ovary?
Primordial follicles
Primary follicles
Secondary follicles
Antral follicles
Which stages of development of the follicles in the ovary occurs independently to the menstrual cycle?
Primordial follicles developing into primary and secondary follicles
After what stage do follicles develop receptor for FSH and require FSH stimulation for further growth?
Secondary follicles develop FSH receptors
What is a dominant follicle?
A follicle that develops further than the rest during a menstrual cycle
A spike in what hormone causes ovulation?
LH
What maintains corpus luteum if ovum becomes fertilised?
HCG produced from the syncytiotrophoblast of embryo maintains corpus luteum
What happens with corpus luteum if egg is not fertilised and how does this affect hormone levels?
Initially corpus luteum produces progesterone and smaller amounts of oestrogen, it degenerates if ovum isnt fertilised and stops producing hormones so there is a drop in progesterone and oestrogen
What does a drop in the oestrogen and progesterone levels cause?
Causes the endometrium to break down and menstruation to occur
Drop in negative feedback to hypothalamus and pituitary also allows LH and FSH to rise
What are the 3 layers of a primary follicle?
Primary oocyte in centre
Zona pellucida
Granulosa cells
What are the two layers of the theca folliculi?
Inner layer- secretes androgen hormones
External layer- smooth muscle and collagen
What is the change seen from development from secondary follicle to antral?
Development of an antrum which is a single fluid filled areas within granulosa cells
What happens in a follicle at ovulation?
LHsurge causes contraction of smooth muscle in external thecal layer bursting follicle. Digestive enzymes from follicle create a hole in ovary wall for ovum to pass through
How doe the granulosa and thecal cells change in corpus luteum?
They become luteal cells producing steroid hormones- particularly progesterone
What is the decidua?
Cells of the stroma (supportive outer tissue of endometrium) converted into a tissue specialised to provide nutrients to the trophoblast
What tissues are derides from the ectoderm?
CNS, skin, hair, teeth, nails
What tissues are derived from the mesoderm?
Bone, Muscle, Heart, connective tissue, blood, kidneys