7.8. Female sexual endocrinology. Flashcards
I. Anatomy of female gonads (just take a look)
1. What are the features of female gonads?
- The female gonads are the ovaries, and these are connected to the uterus via the fallopian tubes.
- In the ovary there is a cortex, medulla, and hilum.
I. Anatomy of female gonads (just take a look)
2. What are the structures in female ovary?
- In the ovary there is a cortex, medulla, and hilum.
I. Anatomy of female gonads (just take a look)
3. What is the cortex of ovary lined with? What is the function?
- The cortex is lined with germinal epithelium and the female’s oocytes – each egg within its own follicle.
- The dominant follicle is the site of steroid hormone synthesis, which can be paracrine or endocrine in function.
=> Both functions act to support the ova development and potential fertilization, as well as acting on tissues such as the breasts, uterus, and bones (increases OPG activity => resulting in bone formation)
II. Cyclic reproductive function – menstrual cycle
1. What are the main features of Cyclic reproductive function – menstrual cycle?
II. Cyclic reproductive function – menstrual cycle
2A. What are the phases of ovarian cycle?
I – Follicular phase
- Development of follicles stimulated by FSH
- Rise in ovarian [estradiol] triggers a LH surge, which causes ovulation
- Duration is quite variable (~14 days)
II – Luteal phase
- Follicle transforms into a corpus luteum
- Length of this phase is constant = 14 days
- w/o pregnancy, the corpus luteum dies -> menses
II. Cyclic reproductive function – menstrual cycle
2B. What happen in follicular phase of ovarian cycle?
- Development of follicles stimulated by FSH
- Rise in ovarian [estradiol] triggers a LH surge, which causes ovulation
- Duration is quite variable (~14 days)
II. Cyclic reproductive function – menstrual cycle
2C. What happen in Luteal phase of ovarian cycle?
- Follicle transforms into a corpus luteum
- Length of this phase is constant = 14 days
- w/o pregnancy, the corpus luteum dies -> menses
II. Cyclic reproductive function – menstrual cycle
3A. What are 3 phases of endometrial cycle?
I – Menses
II – Proliferative phase
III – Secretory phase
II. Cyclic reproductive function – menstrual cycle
3B. In endometrial cycle,
what happen in I – Menses?
- 2 to 6 days
- Marked by menstrual bleeding
=> decline of estrogen and progesterone levels; the endometrial functional layer will be destroyed
II. Cyclic reproductive function – menstrual cycle
3C. In endometrial cycle,
what happen in II – Proliferative phase?
- Endometrium proliferates thanks to progesterone
II. Cyclic reproductive function – menstrual cycle
3D. In endometrial cycle,
what happen in III – Secretory phase?
- Stroma cells of endometrium enlarge and become more eosinophilic – necessary during pregnancy
III. Ovarian hormone synthesis
1. What happen during Ovarian hormone synthesis?
III. Ovarian hormone synthesis
2. How is free cholesterol transferred into the mitochondrial matrix?
- Free cholesterol is transferred into the mitochondrial matrix in a steroidogenic acute regulatory (StAR) protein dependent manner
III. Ovarian hormone synthesis
3. What happen during Androgen production in the ovary?
IV. Regulation of Ovarian hormone synthesis
1. What happen in Regulation of Ovarian hormone synthesis?
IV. Regulation of Ovarian hormone synthesis
2. What is the first important hormone produced in Regulation of Ovarian hormone synthesis?
- Neurons in the arcuate nucleus and the pre-optic area of the HT secrete GnRH
IV. Regulation of Ovarian hormone synthesis
3. What is the molecular mechanism of GnRH?
- GnRH binds to Gq-coupled receptors on the gonadotroph membrane, which cause the release of the gonadotropic cells (LH + FSH)
IV. Regulation of Ovarian hormone synthesis
4. What is the role of gonadotropic
cells (LH + FSH)?
- LH binds to receptors (Gs) on theca cells
- FSH binds to receptors (Gs) on granulosa cells
+) PKA stimulates synthesis of enzymes: activins + inhibins
IV. Regulation of Ovarian hormone synthesis
5. The role of activins and inhibins
- FSH binds to receptors (Gs) on granulosa cells
=> PKA stimulates synthesis of enzymes: activins + inhibins - The activins and inhibins feed back only on FSH production by the anterior pituitary
+) Activin = positive feedback, inhibin = negative feedback
IV. Regulation of Ovarian hormone synthesis
6. The role of The estrogens and progestins in hormone synthesis regulation
IV. Regulation of Ovarian hormone synthesis
7. What is the consequence of High level of estradiol (during the late follicular phase)
High level of estradiol (during the late follicular phase) enhances the sensitivity of gonadotrophs to GnRH
IV. Regulation of Ovarian hormone synthesis
8. What are the hormones regulate LH + FSH production?
CRH, β-endorphin, PRL and leptin/ghrelin regulate LH + FSH production
IV. Regulation of Ovarian hormone synthesis
9. Make a schematic diagram of Regulation of Ovarian hormone synthesis
V. Regulation of gonadotropin synthesis
1. What happen in Regulation of gonadotropin synthesis?
V. Regulation of gonadotropin synthesis
2. What happen after Binding of GnRH to the receptor?
Binding of GnRH to the receptor on the gonadotrophic membrane activates the PLC pathway:
Gq -> ↑PLC
-> IP3 -> ↑[Ca2+]IC
=> LH + FSH release
V. Regulation of gonadotropin synthesis
3. What is the role of PKC in Regulation of gonadotropin synthesis?
- PKC stimulates gene transcription and synthesis of gonadotropins (LH + FSH) by phosphorylation
V. Regulation of gonadotropin synthesis
4. What is the role of estradiol In the late follicular phase?
In the late follicular phase, estradiol enhances the GnRH sensitivity in the anterior pituitary, which causes a much larger release of LH
VI. Oocyte maturation
1. What are the events in Oocyte maturation?
VI. Oocyte maturation
2. What does Primordial germ develop into?
Primordial germ cells develop into oogonia
-> oogonia undergo mitotic divisions
-> some enter meiosis 1 and become primary oocytes
(- Meiosis 1 arrest at prophase 1 (initially, this arrest is caused by the lack of proteins required for meiosis 1 to occur – later, higher levels of cAMP maintains arrest))
VI. Oocyte maturation
3. How does Primordial follicles form?
Primordial follicles form when primary oocytes are surrounded by pre-granulosa cells
VI. Oocyte maturation
4. What happen when Primary follicles form?
Primary follicles form granulosa cells (cuboidal)
- Zona pellucida formscontains ZP1, 2, 3 (proteins)
- Number of FSH receptors on the granulosa cells increase
VI. Oocyte maturation
5. What happen when secondary follicles form?
VI. Oocyte maturation
6. What happen when Tertiary (antral) follicles form?
antrum develops within
(fluid-filled space)
VI. Oocyte maturation
7. What are the 3 types of Granulosa cells of the tertiary and Graafian follicle?
- Mural granulosa cells:
- farthest away from oocyte, most
metabolically active, large quantities of LH receptors - Cumulus granulosa cells (cumulus oophorus):
- innermost = corona radiata, shed with oocyte upon ovulation - Antral granulosa cells:
- faces the antrum, after ovulation they become luteal cells