Female Reproductive Physiology Flashcards
What are the 3 layers of the ovaries?
- Surface
- Connective tissue capsule covered with layer of simple cuboidal epithelium
- Cortex
- Peripheral part, connective tissue containing ovarian follicles (one oocyte surrounded by single layer of cells)
- Medulla
- Central part, connective tissue with blood vessels
What is the surface of the ovaries formed from?
- Connective tissue capsule covered with layer of simple cuboidal epithelium
What is the cortex of the ovaries formed from?
- Peripheral part, connective tissue containing ovarian follicles (one oocyte surrounded by single layer of cells)
What is medulla of ovaries formed from?
- Central part, connective tissue with blood vessels
Describe the function of the ovaries?
- Oocyte production
- One mature egg per menstrual cycle, around 400 ovulated during entire reproductive lifespan
- Finite number of eggs which declines with increasing age
- Steroid hormone production
- Oestrogen develops female secondary sexual characters
- Progesterone prepares endometrium for implantation
- 50% of testosterone produced by ovaries before menopause
How does the number of eggs change with age?
Declines
What hormone is responsible for female secondary characteristics?
Oestrogen
What is oogenesis?
Differentiation of the ovum (egg cell) into a cell competent to further develop when fertilised
What is a diploid and haploid cell?
Diploid cell = cell that contains 2 complete set of chromosomes (46 chromosomes)
Haploid cell = cell that contains 1 complete set of chromosomes (23 chromosomes)
What is meiosis and mitosis?
Meiosis = cell division that results in 4 daughter cells, each with half the number of chromosomes of the parent cell, as in the production of gametes
Mitosis = cell division that results in 2 daughter cells with the same number and kind of chromosomes as the parent nucleus
What are gametes?
Gametes = an organism’s reproduction cells, female gametes are ova and male gametes are sperm
Describe the follicular development stage?
- Primordial follicles – primary oocyte arrested in first meiotic division surrounded by one layer of squamous pre granulosa cells
- Primary follicle – oocyte surrounded by zona and cuboidal granulosa cells
- Secondary follicle – increased oocyte diameter and multiple layer of granulosa cells, resumption of first meiotic division
- Tertiary/Graffian follicle – follicular fluid between the cells which coalesce to form antrum, completion of first meiotic division to form secondary oocyte and start of second meiotic division
What are the 2 phases of follicular development?
Preantrum phase (oogonia to secondary follicle)
Antral phase (tertiary follicle to preovulatory)
Describe the chromosomal division during oogenesis?
Before birth - oogonium to primary oocyte (mitosis)
After puberty - primary oocyte to secondary oocyte with production of polar body (meiosis)
What is the endocrine control of ovarian and menstrual cycles known as?
Hypothalamic-pituitary-ovarian axis
Describe the hypothalamic-pituitary-ovarian axis?
- Hypothalamus releases gonadotrophin releasing hormone (GnRH)
- Acts on anterior pituitary gland which releases gonadotrophins (follicle stimulating hormone and leukoinsing hormone)
- These hormones act on ovaries which release oestrogen and progesterone
- These hormones give negative feedback to hypothalamus and anterior pituitary for most of cycle, but from days 12-14 oestrogen gives positive feedback to hypothalamus and anterior pituitary
What effect does gonadotrophin releasing hormone (GnRH) have and where is it released from?
Acts on anterior pituitary gland which releases gonadotrophins (follicle stimulating hormone and luteinizing hormone)
Released from hypothalamus
What effect does FSH and LH have and where are they released from?
These hormones act on ovaries which release oestrogen and progesterone
Released from anterior pituitary
What effect does oestrogen and progesterone have on the hypothalamic-pituitary-ovarian axis and where are they released from?
These hormones give negative feedback to hypothalamus and anterior pituitary for most of cycle, but from days 12-14 oestrogen gives positive feedback to hypothalamus and anterior pituitary
Released from ovaries
Describe the phases of the ovarian cycle?
- Follicular phase – FSH causes follicle to mature and produce oestrogen (inhibiting the development of other follicles)
- Ovulation – an LH surge causes ovulation (follicle rupture and releases a secondary oocyte)
- Luteal phase – ruptured follicles forms a corpus luteum and secretes progesterone (and some oestrogen)
- Menstruation – when the corpus luteum degenerations (forming a corpus albicans), a new ovarian cycle can begin
What happens in the follicular phase of the ovarian cycle?
FSH causes follicle to mature and produce oestrogen (inhibiting the development of other follicles)
What causes ovulation?
A LH surge causes ovulation (follicle rupture and releases a secondary oocyte)
What happens in the luteal phase of the ovarian cycle?
Ruptured follicles forms a corpus luteum and secretes progesterone (and some oestrogen)
How does increase production of oestrogen affect other follices?
Inhibits development
What does the rupture follicle form and what does it do?
Corpus luteum which secretes progesterone and some oestrogen
What is formed when the corpus luteum degenerates?
Corpus albicans
Why in the middle of the ovarian cycle is there a large surge of LH? What does this cause?
Large surge due to positive feedback of oestrogen, causes ovulation
What occurs during the follicular phase and luteul phase?
Follicular - development of follicle
Luteum - progesterone prepares endometrium for implantation
Which of oestrogen and progesterone is dominant in the follicular and luteum phases?
Follicular - oestrogen
Luteum - progesterone
What effect does oestrogen and progesterone have on the endometrium?
Oestrogen - causes it to proliferate and grow
Progesterone - causes vascularisation
What is the medical term for no periods?
Amenorrhoea
What can amenorrhoea occur due to?
-
Problems with regulating hormones
- Hypothalamic or pituitary cause - Hypogonadotropic hypogonadism (low FSH, LH, high prolactin)
- Caused due to
- Functional – excessive weight loss or gain, over exercising or stress
- Chronic medical conditions – diabetes, sarcoidosis, renal disease, TB
- Intracranial space occyping lesion – prolactinoma tumours, cysts
- Infection or trauma – meningitis, intracranial bleed, Sheehan’s
- Drugs – glucocorticoids, anabolic steroids, opiates
- Genetic – Kallmann’s syndrome
-
Problems with ovarian function
- Hypogonadotropic hypogonadism (high or normal FSH and LH)
- Caused due to
- Genetic – Turner’s syndrome, Fragile X
- Ageing – steep decline in ovarian function past 35 years
- POI or POF
- Chronic illness – autoimmune diseases
- Radiotherapy or chemotherapy
- Infection – TB, mumps oophoritis
-
Problems with uterus or outflow tract
- Congenital
- Absent uterus, vagina, lack of Mullerian duct development
- Transverse vaginal septum
- Androgen insensitivity syndrome
- Iatrogenic
- Uterine adhesions or synechiae (Asherman syndrome)
- Radiotherapy – pelvic or cervical
- Congenital
What levels of hormones are seen if amenorrhoea occurs due to problems with regulating hormones?
- Hypothalamic or pituitary cause - Hypogonadotropic hypogonadism (low FSH, LH, high prolactin)
What levels of hormones are seen if amenorrhoea occurs due to problems with ovarian function?
- Hypergonadotropic hypogonadism (high or normal FSH and LH)
What is hypogonadotropic hypogonadism? Where is the cause?
Low FSH, LH, high prolactin
Problems with regulating hormones
What is hypergonadotropic hypogonadism? Where is the problem?
(high or normal FSH and LH)
Problem with ovarian function
What can problems with regulating hormones be caused due to?
- Functional – excessive weight loss or gain, over exercising or stress
- Chronic medical conditions – diabetes, sarcoidosis, renal disease, TB
- Intracranial space occyping lesion – prolactinoma tumours, cysts
- Infection or trauma – meningitis, intracranial bleed, Sheehan’s
- Drugs – glucocorticoids, anabolic steroids, opiates
- Genetic – Kallmann’s syndrome
What can problems with ovarian function be caused due to?
- Genetic – Turner’s syndrome, Fragile X
- Ageing – steep decline in ovarian function past 35 years
- POI or POF
- Chronic illness – autoimmune diseases
- Radiotherapy or chemotherapy
- Infection – TB, mumps oophoritis
What are examples of problems with uterus or outflow tract?
- Congenital
- Absent uterus, vagina, lack of Mullerian duct development
- Transverse vaginal septum
- Androgen insensitivity syndrome
- Iatrogenic
- Uterine adhesions or synechiae (Asherman syndrome)
- Radiotherapy – pelvic or cervical
What are some things involved in the management of amenorrhoea?
- Lifestyle changes
- Optimise control of medical illness
- Stop or change drugs
- Prolactinoma – medical treatment
- Intracranial SOL – surgical treatment
- Vaginal anomalies – surgical treatment
- Uterine adhesion – surgical division hysteroscopic
- Fertility preservation before radiotherapy and chemotherapy
- Fertility treatment such as IVF with own or donor eggs
