Puberty

Question 1

Prepubertal Development:

When does brain growth plateau?

Answer 1

6-8 yrs

Question 2

Are the ovaries essential for female prepubertal development?

Answer 2

No

Question 3

The Migration of the testes to scrotal position is mediated by which 2 ligaments?

Answer 3

Gubernaculum and Suspensory ligaments

Question 4

What kind of activity does the neonatal HPG axis undertake at birth until puberty?

Answer 4

Transient

Question 5

What week does sexual differentation occur?

Answer 5

5-6 Wks

Question 6

Fetal development:

At what week does the hypothalamic neural cells secreted GnRH?

Answer 6

Wk 11

Question 7

Prepubertal testosterone levels:

Fetal: onset of secretion?

Answer 7

Secretion from 8-10 weeks onwards

Question 8

Prepubertal testosterone levels:

Prenatal: Peaks at what week? How much T?

Answer 8

PEaks at wk 13- 15 (2ng/ml)

Question 9

Prepubertal testosterone levels:

Post natal: Peaks when? How much? When is the decline

Answer 9

Peaks @ 3 months after birth (2-3ng/ml)

Postnatal decline at 3-4months.

Question 10

Prepubertal testosterone levels:

What happens to testosterone levels at 1yr after birth? (Concentration?)

Answer 10

Second modest rise until prepubertal peak (9ng/ml)

Question 11

Triggers of puberty:

Sleep, explain?

Answer 11

Earlyin puberty, GnRH is released during sleep -> long term development of pulsative GnRH release w/ positive feedback initiating ovulation or spermatogenesis.

Helps perpetuate further release of LH and FSH from Pit. = Gonadal development.

Question 12

Triggers of puberty:

Leptin?

Answer 12

Before puberty leptin levels rise in proportion to adipose tissue mass (fat levels). Leptin may be a way for the body to tell the hypothalamus that (Dude we got enough long term energy storage lets go). But also there is a growth hormone- induced acceleration of body growth- increase body weight.

Question 13

What trigger puberty, Secondary factors?

Answer 13

• psychological factors (internal)
  
  • happiness vs. stress
• environmental stimuli (external)
  
  • smell
  • photoperiod in some species
    
    • circadian (circa = approximately, diem = day) rhythms
      
      • supra chiasmatic nuclei (tiny region in brain controlling circadian rhythms
    • circannual rhythms
• colours
• temperature (more relevant to animals)

Question 14

Female Tanner stages (5)

Answer 14

P1: Prepubertal.

P2: Early development of subareolar breast bud and small amounts of pubic hair and axillary hair.

P3: Increase in size of palpable breast tissue and areolae, increase in pubic/axillary hair

P4: Breast tissue and areolae protrude above breast level. Further increase in hair development.

P5: Mature adult breast Complete pubic/axillary growth

Question 15

What is the first sign of female puberty?

Answer 15

Thelarche (Breast development)

Question 16

What hormones initiate breast growth?

Answer 16

Oestrogen, Prolactin and GH

Question 17

Male Tanner stages

Answer 17

P1: Prepubertal, testicular volume <1.5ml

P2: Testicular volume between 1.6-6ml. Small amounts of axillary and pubic hair (9-11 year)

P3: Testicular volume 6-12ml, lengthening of penis and areola, increase in pubic/axillary hair (11-12.5 yrs)

P4: Testicular volume 12-20ml, scrotum enlarges + darkens. (12.5-14 yrs) Further increase in hair development

P5: Testicular volume (>20ml). Adult genitalia

Question 18

What hormone is higher during puberty than adulthood (Male + Female)?

Answer 18

LH

Question 19

Reproductive function and maturation is coordinated by the …

Answer 19

Hypothalamic-pituitary-gonadal axis

Question 20

What is the most significant structural remodelling during female puberty?

Answer 20

Uterine Chages

Question 21

What hormones cause uterine remodelling during puberty?

Answer 21

Oestrogen, Progesterone, Prolactin and Growth Factors

Question 22

When does the second stage of sertoli cell and germ cell proliferation occur?

Answer 22

Puberty

Question 23

What does this show?

Answer 23

Endocrine control of puberty and spermatogenesis in males

Question 24

What are the target cells of FSH in Males?

Answer 24

Sertoli cells

Question 25

What are the target cells of LH in males?

Answer 25

Leydig cells

Question 26

What are the target cells of LH in females?

Answer 26

Theca Cells

Question 27

What cells are the target of FSH in females?

Answer 27

Granulosa cells

Question 28

When is the prostate fully functionally grown?

Answer 28

Puberty

Question 29

What characteristics are defined by the sexual dimophism of the musculoskeletal system?

Answer 29

* Enlarged pelvis in females and enlarged shoulders in males * Men: 1.5x more lean body mass and 1.5x more skeleton than women * Women: 2x more body fat

Question 30

What hormones are responsible for the closure of epihpyses?

Answer 30

Oestrogen and Thyroid hormones

Question 31

What are the characteristics of sexual dimorphism of the respiratory system?

Answer 31

* Male larynx grows by 1/3 of its adult size (also laryngeal prominence) * Thickening and lengthening of the vocal cords in males * Lowers pitch of voice.

Question 32

What are the four characteristic features of the pubertal development of the integumentary system?

Answer 32

1. Hair Growth (Male thick, Female Fine) 2. Hypodermic fat (cellulite) accumulation (Females, oestrogen) 3. Activation of sebaceous glands (Testosteron and oestrogen) 4. Development of axillary and anogenital 'sweat' glands. * Controlled by androgen * secrete viscous odorless sweat, proteins and fat substances. * activated by sympathetic nerves and sexual foreplay.

Question 33

What are the characteristics of the pubertal changes of the cardiovascular system? (4)

Answer 33

* Increased blood volume * Increased interstitial fluid (oestrogen caused) * Decreased plasma cholesterol * Possibility of anaemia (Females)

Question 34

What are the characteristic changes in the nervous system during puberty?

Answer 34

Mental maturation Fatigue and Depression Sexual Drive Sexual Behaviour

Question 35

What is sexual age determined by in males and females?

Answer 35

Males: Testicular and penile size, hair growth Females: Thelarche, menarche, hair growth

Question 36

What % increase in body size occurs during puberty?

Answer 36

20%

Question 37

What years does puberty occur in females

Answer 37

9-13

Question 38

Whats years does puberty occur in males?

Answer 38

11-15 yrs

Question 39

Does puberty last longer in mals or females?

Answer 39

Males

Question 40

Answer 40

Question 41

Answer 41

Question 42

What is Precocious Puberty?

Answer 42

Dveelopment of secondary sexual characteristics before the age of: 8yrs in Women 9yrs in Men

Question 43

What % of the population shows precocious or delayed puberty?

Answer 43

5%

Question 44

What are he two main types of precocious puberty?

Answer 44

Gonadotrophin-independent (Peripheral) Gonadotrophin-dependent

Question 45

Gonadotrophin-independent precocious puberty caused by

Answer 45

Testicular disorders and tumors Ovarian disorders and tumors

Question 46

Gonadotrophin-independent precocious puberty causes (symptoms)

Answer 46

Increased gonadal steroid secretions Increased adrenal androgen (in males)

Question 47

Gonadotrophin-dependent PP is caused by:

Answer 47

CNS tumors Other pathologies and lesions Idiopatic: 2/3rds of cases, 90% of female precocious puberty

Question 48

Gonadotrophin-dependent PP causes (symptoms)`:

Answer 48

Early reactivation of the HPG axis Increased production of GnRH/ Gonadotrophins

Question 49

What is Delayed Puberty?

Answer 49

Failure to achieve sexual maturation at two years after the mean normal age of puberty • girls (normally 9-13 years) • boys (normally 11-15 years)

Question 50

What is delayed puberty caused by?

Answer 50

**Hypogonadotrophic hypogonadism** **Hypergonadotrophic hypogonadism**

Question 51

What causes hypogonadotrophic hypogonadism?

Answer 51

CNS disorders & gonadotrophin deficiency Gonadal dysgenesis and failure

Question 52

What causes hypergonadotrophic hypogonadism?

Answer 52

LHR (receptor) and FSHF mutations Turner Syndrome, 45X female Klinefelter syndrome, 47XXY male

Question 53

What is Anovulatory PCOS?

Answer 53

Chronic inability to produce preovulatory follicles, - no ovulation and mestrual cycle (amenorrhea). Characterised by: Hyperandrogenism, masculinsed body shape, hirsutism, obesity, acne

Question 54

How many women have PCOS and it causes what % of female infertility and anovulatory infertilty?

Answer 54

23% of all women have it 10% of all women infertility 50% of all anovulatory infertility

Question 55

Male erectile dysfunction affects how many men?

Answer 55

\>150 M men worldwide

Question 56

What is male erectile dysfunction caused by?

Answer 56

Vascular aetiology: - Atheroschlerosis of pudendal artery and branches - Failure of veno-occlusive mechanism (venous leak) - Impaired smooth muscle relaxation

Question 57

What is the danger of untreated cryptorchidism?

Answer 57

Infertility Increased incidence of testicular cancer in males

Question 58

6% of isosexual female puberty causes

Answer 58

malignancies of the female genital tract

Question 59

What female genital tract malignancy risk factor is increase by 6 fold in teenage pregnancy?

Answer 59

Gestational trophoblastic tumour

Question 60

Teenage girls whose mothers recieved diethylstilboestrol (DES) during pregnancy have an increased risk of ...

Answer 60

Clear cell carcinoma of the vagina

Question 61

What percent of precocious puberty is idiopathic in females?

Answer 61

66%

Question 62

What is the female:male ratio of precocious puberty?

Answer 62

10:1

Question 63

What does a GPR54 mutation cause?

Answer 63

Delayed puberty