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Module 203, Theme 2- Reproductive System, Fetal Development, Pregnancy and Birth > T2 L20 Physiology of Puberty > Flashcards

T2 L20 Physiology of Puberty Flashcards

(67 cards)

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1
Q

Define puberty

A

The stage of physical maturation in which an individual becomes physiologically capable of pro-creation (sexual reproduction)

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2
Q

List some of the physical changes that occurs during puberty (both male + female)

A

Growth spurt

Secondary sex characteristics

Menarche/spermatogenesis

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3
Q

Between what ages do girls begin their growth spurt? How long does it last?

A

Age: 8 - 14 yrs
Duration: 2.5 yrs

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4
Q

How many cm do girls grow per year during their growth spurt?

A

6 - 10 cm (per year)

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5
Q

Between what ages do girls begin to have breast growth? What is this called?

A

Age: 8 - 13 yrs ( avg: 11 yrs )
THELARCHE

NOTE: This is usually the first pubertal sign

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6
Q

Between what ages do girls begin to grow pubic hair? What is this called?

A

9 - 13 yrs

PUBARCHE

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7
Q

What % of girls have pubarche as their first pubertal sign?

A

25%

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8
Q

Between what ages do girls begin to grow axillary (armpit) hair? What is this called?

A

Age: 9.5 - 15 yrs

ADRENARCHE

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9
Q

Between what ages do girls begin to menstruate? What is this called?

A

10 - 16 yrs ( avg: 13 yrs )

MENARCHE

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10
Q

What may adrenarche follow?

A

Menarche

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11
Q

When is H-P-G synchrony established? (in females)

A

Established in fetal life

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12
Q

What happens to GnRH release before puberty? (in females)

A

GnRH release is suppressed via neural mechanisms

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13
Q

Between what ages does mini puberty occur? What happens? (in females)

A

At 6-9 yrs

Pulsatile nocturnal GnRH release begins

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14
Q

What test is carried out to check for puberty?

A

A LHRH test

If this hormone is switched off the person is not experiencing puberty.

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15
Q

What endocrine changes occur during puberty?

A

Pulsatile GnRH release (nocturnal) every 90-120 min - (between 6 to 9 yrs)

Increased GnRH leads to increased FSH and LH
Ovaries/testes become sensitized to the effects of FSH and LH

Final phase: development of positive/negative feedback mechanism

ACTH stimulates the adrenals – Pubic & Axillary hair

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16
Q

What is the role of the testes?

A

Production of gametes (sperms)
-Sertoli cells under FSH control

Production of androgens (Testosterone)

  • Leydig cells under LH control
  • 95% from testes, 5% from adrenals
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17
Q

What is testosterone converted to in target organs?

A

DHT (dihydrotestosterone)

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18
Q

What happens in the follicular phase of the ovarian cycle?

A

Initially oestrogen rises (due to FSH) with LH surge in mid cycle

Ovulation occurs

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19
Q

What happens in the luteal phase of the ovarian cycle?

A

Negative feedback after ovulation

No further ovulation in the same cycle

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20
Q

What is the age of menarche related to?

A

General health

Genetic

Nutritional factors

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21
Q

What is happening to the mean age of menarche?

A

Mean age is falling at a rate of 4 months per decade

Mean age in 1840 = 16.5 y; 1990 = 12.8 y

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22
Q

How many girls reach menarche whilst in primary school?

A

1 in 8

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23
Q

What is the mean weight and body fat % during menarche?

A

Mean weight at menarche is 47.8kg

16-24% fat

NOTE: Without enough fat stores, the body does not undergo menarche

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24
Q

Which groups of people are likely to have a late onset of menarche?

A

Athletes

Patients with anorexia

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25
Which hormone is responsible for axillary and pubic hair?
Adrenal androgens
26
BONUS: Which zone of the adrenal cortex produces adrenal androgens?
Zona reticularis
27
Which hormone stimulates the zona reticularis?
ACTH (from pituitary gland)
28
At what age do girls start producing DHEAS & androstenedione? At what age do girls have adequate levels of DHEAS & androstenedione?
Starts producing : 6 yrs Adequate levels : 8 yrs
29
At what age do boys start producing DHEAS & androstenedione? At what age do boys have adequate levels of DHEAS & androstenedione?
Starts producing : 8 yrs Adequate levels : 10 yrs
30
What test can be carried out to find out which androgens are responsible for adrenarche?
Urine profile test
31
What is the chronological order of puberty in girls?
1) Growth spurt 2) Breast development 3) Pubic hair 4) Axillary hair 5) Menarche
32
What is the chronological order of puberty in boys?
1) Testicular volume 2) Penile length 3) Pubic hair 4) Growth spurt 5) Axillary / Facial hair 6) Deep voice
33
Below what age does early or precocious puberty begin in girls and boys?
Girls – under 8 yrs | Boys – under 9 yrs
34
After what age does delayed puberty begin in girls and boys?
Girls – over 14 yrs | Boys – over 14 yrs
35
What is precocious puberty?
Early or Premature puberty Presence of true pubertal features at an young & inappropriate age
36
Describe the two subtypes of precocious puberty
Central or True precocious puberty -Gonadotrophin dependent Peripheral or Pseudo-precocious puberty -Gonadotrophin independent
37
What are the normal variants of precocious puberty?
Premature Thelarche : isolated breast development. Usually seen in children <2-3 yrs of age. Do a LHRH test and investigate the gonadal axis. Premature Adrenarche : isolated pubic hair development (take caution as this can be the first pubertal sign in some children)
38
Name the concerns raised by early onset of puberty
Possible underlying sinister cause -Boys – up to 80% Emotional & pyscho-social upheaval at an inappropriately young age Early cessation of growth leading to decreased final adult height
39
What is a hypothalamic hamartoma?
A benign tumour of the hypothalamus
40
What can a hypothalamic hamartoma lead to?
Central precocious puberty
41
What can high oestradiol levels be indicative of?
Activated pubertal axis
42
How can central precocious puberty be treated?
Long acting LHRH analog therapy - sustained supra-physiological LHRH levels - paradoxical cessation of gonadotrophin release - stops further pubertal progression
43
What happens when the LHRH analog therapy is stopped?
Pubertal progression resumes
44
At what age is the LHRH analog therapy usually stopped?
10 - 12 years
45
What is pseudo-precocious puberty
Oestrogen and testosterone are secreted by tumours in the adrenal gland or in the testis or ovaries The ovaries or the testes do not mature (unlike in precocious puberty)
46
What could be the underlying cause of iso-sexual or feminising features in pseudo-precocious puberty? (in females)
MAS (McCune-Albright syndrome) : a disorder that affects the bones, skin, and several hormone-producing (endocrine) tissues Ovarian/Adrenal Exogenous oestrogens
47
What could be the underlying cause of heterosexual or masculinising features in pseudo-precocious puberty? (in females)
CAH (Congenital Adrenal Hyperplasia) Ovarian/Adrenal Exogenous androgens
48
What could be the underlying cause of iso-sexual or feminising features in pseudo-precocious puberty? (in males)
CAH (Congenital Adrenal Hyperplasia) Adrenal/Leydig cell tumor Exogenous androgens
49
What could be the underlying cause of heterosexual or masculinising features in pseudo-precocious puberty? (in males)
Adrenal Exogenous oestrogens
50
What can be the effect of androgens in females?
Androgens block the normal cycle and can cause conditions like PCOS
51
Describe the characteristics of delayed puberty
- Absence of true pubertal onset at an appropriate age - Not necessarily lack of periods in a girl - X-files – very important BUT there are some normal variants with constitutional growth & pubertal delay
52
What concerns are raised by a delay in puberty?
Possible sinister underlying cause Fear that puberty will never occur Emotional and psychosocial upset of immaturity, especially when associated with short stature Long term sequelae: Reduced bone mineralization
53
What is Klinefelter syndrome?
A chromosomal abnormality 47 XXY / Multiple X
54
How many male infants are affected by Klinefelter syndrome?
1 in 1000
55
What are the effects of Klinefelter syndrome?
Behavioural problems Androgen deficiency Azoospermia / Infertility (Micro genitalia which can result in Sex change) Lifelong testosterone replacement therapy
56
What is Turner syndrome?
Chromosomal abnormality 45 X (one missing X chromosome)
57
How many female infants are affected by Turner syndrome?
1 in 2000 | Surprisingly common
58
What are the effects of Turner syndrome?
Triad - Short stature, streak gonads, primary amenorrhoea Dysmorphic features – Webbing of neck, cubitus valgus Coarctation of aorta, horse shoe kidneys
59
What is an early clue for Turner syndrome?
Lymphedema
60
How is Turner syndrome treated?
- Growth Hormone therapy - Pubertal induction + ongoing HRT - Active monitoring to detect co-morbidities - Assisted conception NOTE: Exclude co-existing congenital anomalies first
61
What is Kallmann syndrome?
A condition that causes hypogonadotrophic hypogonadism. Leads to GnRH deficiency Present at birth
62
What could be a sign of Kallmann syndrome in early infancy?
Undescended testicles or a small penis
63
Name another presentation of Kallmann syndrome
Loss of smell
64
How is hypogonadotrophic hypogonadism treated?
Lifelong testosterone treatment
65
What is the normal variant for delayed pubertal growth?
(Constitutional delayed growth & puberty) Late onset of puberty Bone age delayed slightly Family history is often present
66
Is the normal variant for delayed pubertal growth more common in boys or girls?
BOYS
67
Do people that fall within the normal variant for delayed pubertal growth reach their adult height?
YES NOTE: Pubertal induction is sometimes necessary

Module 203, Theme 2- Reproductive System, Fetal Development, Pregnancy and Birth (17 decks)

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