Repro Session 3 Flashcards
What is pubarche?
Development of axillary and pubic hair
What is menarche?
1st menstrual period
What is adrenarche?
Onset of an increase in androgen secretion
What is puberty?
Stage of human development when sexual maturation and growth are completed form the primary sexual characteristics established before birth
What is the fixed order of events seen in puberty?
Accelerated somatic growth, maturation of primary sexual characteristics, appearance of secondary sexual characteristics, menstruation/spermatogenesis begin
What accounts for the 10% difference in height between men and women?
Women undergo somatic growth earlier and for less time due to closure of epiphysis by oestrogen
What does genital maturation depend on in males?
Testosterone
Why does the reproductive system not work before puberty?
Low GnRH secretion –> low hormone levels so LH and FSH are insufficient
Where is there low level androgen secretion from prior to puberty?
Adrenals
What initiates onset of puberty?
Brain increasing GnRH –> steady rise in LH and FSH
How does nutrition affect onset of puberty?
Critical weight of 47 kg of menarche needs to be met and correlation between leptin and menarche
What is the supporting evidence that nutrition influences the onset of puberty?
Obese girls experience early menarche, malnutrition –> delayed menarche, primary amennorhoea in lean athletes, body fat set point seen in girls with fluctuating weight due to anorexia nervosa
What suggests an association between onset of puberty and seasonal breeding seen in species where changes in day length alter pineal gland melanin secretion?
Pineal tumours influencing onset of puberty in humans
What action does TSH have in both sexes in the HPG axis?
Increases metabolic rate and promotes tissue growth
What are the results of increased growth hormone on the HPG axis in puberty?
Increases insulin to descrease sex-hormone binding globulin and IGF-gpbinding protein and acts on liver to increase IGF-1 to cause somatic and neuronal growth and myelin secretion
What precedes the phenotypic changes seen in puberty by several years?
Increase in nocturnal pulsatile LH secretion during REM sleep
What happens at 9-12 years to lead to gonadal development?
(Less sensitive hypothalamic neurones?) LH and FSH levels rise
What are the results of the LH and FSH rise at ~10 y.o. In males?
Spermatogenesis and androgen secretion
What are the affects of increased androgen secretion in males during puberty?
Growth of sex accessory structures (prostate), male secondary sex characteristics, retention of mineral in body for bone and muscle growth
Which cells in the male secrete oestrogen?
Sertoli
What is the pattern of phenotypic changes seen in male puberty?
Testicular volume increases –> public hair grows and spermatogenesis occurs –> growth spurt –> adult genitalia and pubic hair develop
What is the pattern of phenotypic changes seen in female puberty?
Thelarche and pubic hair growth –> adrenarche, growth spurt and onset of menstrual cycle –> menarche, adult pubic hair and breasts
What are the female secondary sex characteristics?
Growth of pelvis, SC fat, reproductive organ and genitalia growth
What effects does increasing androgen release by the adrenal glands have on the female during puberty?
Growth of public hair, lowering of voice, growth of bone and increased secretion from sebaceous glands
Is the LH surge in the first ovarian cycle usually enough for ovulation?
No
What is considered normal pubertal development in boys?
Age of start (yrs): 12.5
First sign of puberty: testicular volume
What is considered normal pubertal development in girls?
Age of start (yrs): 11.5
First sign of puberty: breast development
Growth velocity (cm/yr): 9.0
Duration (yrs): 2.4 +/- 1.1
What are the 5 stages of Tanner standard for girls?
Breast: B1-5
Pubic hair: Pu1-5
Axillary hair: A1-5
Menarche
What are the 5 stages of Tanner standard used in male puberty?
Testicular volume > 4 ml: Te Penis enlargement: G1-5 Pubic hair: Pu1-5 Axillary hair: A1-5 Spermarche
How does prepubertal and pubertal growth velocity compare?
Pubertal approx 2/3 X greater than prepubertal
When does male puberty usually occur?
9-14 y.o.
When does female puberty usually occur?
8-13 y.o.
What affects the precise timing of the LH surge during the ovarian cycle?
Environmental factors such as day length and altitude
What is precocious puberty?
Onset of puberty >2 s.d. before average age (girls
What is the prevalence of precocious puberty?
1 in 5000 to 1 in 10,000
What two types of precocious puberty are there?
Gonadotrophin dependent (central) and gonadotrophins independent (neurological)
What are the causes of central precocious puberty?
Tumours (gliomas, astrocytomas, hCG-secreting germ cell)
CNS trauma/injury (infection, radiation, surgery)
Harmatoma of the hypothalamus
Congenital: hydrocephalus, arachnoid cysts
Gonadotrophin secreting tumour
Why is neurological precocious puberty known as precocious pseudopuberty?
Secondary sexual characteristics arise independent of the HPG axis therefore gonadotrophins are not involved
What are the hormone changes in neurological precocious puberty?
Raised testosterone and oestrogen causing suppression of LH and FSH with no pulsatile GnRH
What are the causes of neurological precocious puberty?
Congenital adrenal hyperplasia
Tumours (hCG-secreting in liver, pineal, mediastinal, choriocarcinomas of gonads)
Testotoxicosis
Therapeutic/accidental exogenous androgen exposure
What is testotoxicosis?
Also known as familial male precocious puberty it is an autosomal dominant condition causing rapid physical growth, skeletal maturation and sexual aggression at 2-3 y.o.
What can delayed puberty be define as?
Initial physical changes of puberty not present (girls 13 y.o. or 16 y.o. primary amennorhoea, boys 14 y.o.) or the interval between first signs of puberty and menarche/completed genital growth >5 years
What are the two categories of cause of delayed puberty?
Gonadal failure (hypergonadotrophic hypogonadism) and gonadal deficiency
What can cause gonadal failure leading to delayed puberty?
Turners syndrome, post malignancy (itself or Tx), polyglandular autoimmune syndromes
How is Turner’s syndrome treated?
GH and sex hormone substitution
What can cause gonadal deficiency leading to delayed puberty?
Rare gene defects inactivating FSH/LH/their receptors
Congenital hypogonadotrophic hypogonadism (+anosmia)
Hypothalamic/pituitary lesions due to tumour or radiotherapy
What is thelarche?
Development of the breast
What are the 3 stages of menopause?
Pre-menopause, menopause and post-menopause
What happens in the pre-menopausal stage of the menopause?
~40 y.o. Changes in mestrual cycle seen as follicular phase shortens (seen earlier as decrease in oestrogen by asymptomatic)
Describe the hormonal changes seen in premenopause.
Low oestrogen, raised LH, very raised FSH
What is the affect on ovulation and fertility of premenopause?
Ovulation early/absent and fertility decreases
What is the clinical definition of menopause?
12 continuous months with no menstrual activity
When is the average age of menopause?
49-50
How many follicles can develop at the menopause?
None
What are the effects of the large decrease in oestrogen in the menopause?
Regression of endometrium, shrinkage of myometrium, thinning of cervix, reduction in vaginal and skin tone, involution of breast tissue, loss of pelvic and bladder tone causing urinary incontinence
What is the name given to the symptom experienced when vascular changes in the menopause allow transient rises in skin temperature and flushing?
Hot flushes
Why do some menopausal women experience osteoporosis?
Low oestrogen enhances osteoclasts and removes stimulation of osteoblasts
At what rate does bone mass decrease following the menopause?
2.5% per year
What are the benefits of HRT?
Relieves menopausal symptoms, improves well-being and limits osteoporosis
What is HRT not advised for?
First line for osteoporosis or cardioprotective effect
Describe the end of reproductive life in the male.
No obvious decline in androgen levels, only gradual decline in testosterone levels therefore sperm production continues
When should LH and FSH be measured in menstrual dysfunction?
Beginning of cycle
Describe the regularity of the menstrual cycle across reproductive life.
Best between 20-40 y.o. as cycle is longer after menarche and shorter premenopause
How might a polyp in the female reproductive tract present?
Irregular bleeding +/- bleeding after intercourse
If a polyp in the female reproductive tract has metaplastic or dysplastic tissue where in the polyp will this be?
At the base
What pathology causes an irregular endometrial wall visible on hysterescopy?
Hyperplasia
Why does endometrial cancer have a good mean 5 year survival rate?
Presents early
What is the implication of a BRCA gene mutation in endometrial cancer?
Likely clear cell tumours and to be more aggressive
How does endometrial cancer commonly present?
Post menopausal bleeding
What type of pts are at an increased risk of endometrial cancer?
PCOS
What is the mean blood loss per menstrual cycle?
37-43 ml
When is the majority of blood lost in menses?
First 48 hours
What proportion of the 9-14% of women that lose >80 ml of blood per menstrual cycle are anaemic?
60-70%
Give some causes of menstrual dysfunction that present as an abnormality in the amount of blood lost.
Abnormal clotting, fibroids, IUCD, cancer, progesterone contraception, DUB
What are fibroids?
Myometrium tissue arranged in a whirled pattern that can be subserous, intramural or submucous
What is dysfunctional uterine bleeding?
Heavy bleeding with no recognisable pathology, pregnancy or general bleeding disorders
When is DUB common?
Premenopause
What does biopsy of the endometrium in DUB during premenopause show?
Evidence of dysynchronous hormones
What questions are useful when considering menorrhagia?
Any flooding, passing large clots, need for double protection or time off work?
What is the most likely cause of amennorhoea?
Pregnancy
What is primary amennorhoea?
Absence/failure of ovary causing failure of menses by 16 y.o. or if secondary sexual characteristics have failed to appear by 13 y.o.
What is secondary amennorhoea?
Cessation of menses following menarche
What is cryptomenorrhoea?
Where blood is produced but cannot exit e.g. uterine stenosis or imperforate hymen
What uterine/endometrial causes of amennorhoea are there?
Surgical menopause, laser ablation of basalis endometrium
What ovarian causes of amennorhoea are there?
Turner syndrome, primary ovarian insufficiency/premature ovarian failure
How can microprolactinoma cause amennorhoea?
Causes excess of prolactin causing HPG axis to fail leading to amennorhoea and galactorrhoea
What hypothalamic disorders can lead to amennorhoea?
Eating disorders, exercise, stress, thyroid dysfunction, idiopathic
How can low weight lead to amennorhoea?
Low weight –> lack of adipose –> low oestrogen so HPG axis uncontrolled
Which arteries are found in the germinalis layer of the endometrium?
Spiral and basal
Which arteries are found in the myometrium?
Arcuate arteries
