L29 Reproductive System Flashcards
The gonads have dual functions…
To secrete sex hormones and to produce gametes
The testes secrete…
Androgens (and a small amount of estrogens)
The ovaries secrete…
Oestrogens, progesterone in preparation for pregnancy (and a small amount of androgens)
The myometrium is the…
Muscle supporting the uterus
The endometrium is the…
Inner layer of the uterus
Oocytes are formed in the ovary…
a) throughout life
b) for around 40 years after birth
c) during early development
d) during adolescence
c) during early development
The formation of oocytes is arrested in…
Prophase of meiosis I
The arrested oocytes exist within…
Primordial follicles (of which there are 7 million)
By menarche there are how many oocytes remaining?
About 300,000
The dieing off of the majority of oocytes is known as…
Atresia
Of the oocytes remaining at menarche how many develop further?
About 30,000
Of the the fully developed oocytes, how many are released by ovulation?
About 500
The ovarian cycle is made up of 3 phases…
- Follicular phase
- Ovulation
- Luteal phase
The ovarian cycle concerns the…
Maturation of an oocyte and the release of an ovum
The follicular phase is subdivided into 3 phases…
I. Pre-antral
II. Antral
III. Pre-ovulatory
In the pre-antral phase the primordial follicles grow into…
Mature pre-antral follicles
The growth of primordial follicles is stimulated by…
Paracrine factors
This hormone prevents all the follicles from developing at once…
Antimüllerion hormone
The antral phase is marked by the appearance of…
Fluid filled antra (or atria)
During the antral phase, growth depends on…
Follicle stimulating hormone (FSH) rather than paracrine factors
The primary follicle can be distinguished from the primordial follicle as…
It is larger, has a zona pellucida and the granulosa cells are more cuboidal in shape
The dominant follicle is selected in the…
Antral phase
The dominant follicle becomes a significant…
Steroidogenic gland
The theca cells surrounding the secondary follicle (antral phase) catalyse…
Androgen (androstenedione) production from cholesterol
Granulosa cells contain…
Aromatase which converts androstenedione into estrogens
During the preovulatory phase there is a surge in…
Luteinizing hormone (LH)
In response to the increase in LH during the preovulatory phase, the dominant follicle…
Completes its first meiotic division and arrests in metaphase of meiosis II
The dominant follicle is also known as the…
Graafian follicle
The first division of the Graafian follicle produces a…
Haploid secondary oocyte (egg) + polar body
During ovulation an inflammatory event…
Erodes the wall of the ovary and follicle
During ovulation what is released into the peritoneal cavity?
Oocyte, zona pellucida and corona radiata
The corona radiata is crucial for the capture of the oocyte by the…
Fimbriae
Remnants of the follicle form the…
Corpus luteum
The corpus luteum produces…
Steroid hormones
The luteal phase is marked by the…
Development of the corpus luteum
During the luteal phase the granulosa cells fill with…
Lipid
A major product of the luteal phase is…
Progesterone
Due to the increase in LH, oestrogen levels during the luteal phase…
Decrease (but later rebound)
If there is no pregnancy, the corpus luteum is broken down to the…
Corpus albicans
If there is pregnancy the hormone…
human chorionic gonadotropin (hCG) is released
Hypothalamic and pituitary hormones involved in ovarian cycle (3)…
- Gonadotropin releasing hormone (GnRH)
- Follicle stimulating hormone (FSH)
- Luteinizing hormone (LH)
Ovarian hormones involved in the ovarian cycle (3)…
- Oestrogen
- Progesterone
- Inhibin A & B
LH acts on theca cells to promote…
Androgen production
LH acts on granulosa cells to secrete…
Progesterone
LH maintains the…
Corpus luteum
Ovulation is triggered by…
A surge in LH in the last 1-2 days of the cycle
The release of GnRH is…
Pulsatile
Low frequency GnRH release is associated with increased…
FSH
High frequency GnRH release is associated with increased…
LH
FSH prevents apoptosis of…
Antral follicles
Aromatase levels are increased by…
FSH
Aromatase converts…
Androgens to estrogens
In the late follicular phase (preovulatory), FSH induces…
LH receptors in granulosa cells
Oestrogens are the dominant hormone in which phase?
Follicular phase (pre-ovulation)
Progesterone is the dominant hormone in which phase?
Luteal phase (post-ovulation)
Inhibin A and B represses secretion of…
FSH
Inhibin A and B are secreted by granulosa cells in both…
The follicular phase and the corpus luteum
