Physiology of Puberty Flashcards
1
Q
Define Puberty
A
- The stage of physical maturation in which an individual becomes physiologically capable of pro-creation (sexual reproduction)
2
Q
Physical Changes in Puberty
- … spurt
- … … characteristics
- M…/s…
A
- Growth spurt
- Secondary sex characteristics
- Menarche/spermatogenesis
3
Q
Physical Changes in Girls
- … …
- 8 - 14 yrs
- 6 - 10 cm / yr peak
- 2.5 yrs duration
- … … (…)
- 8 - 13 yrs ( 11 yrs )
- Usually the first sign
- … … (…)
- 9 - 13 yrs
- 1st Pubertal Sign in …%
- … … (…)
- 9.5 - 15 yrs
- May follow Menarche
- … (…)
- 10 - 16 yrs ( 13 yrs )
A
-
GROWTH SPURT
- 8 - 14 yrs
- 6 - 10 cm / yr peak
- 2.5 yrs duration
-
BREAST GROWTH (Thelarche)
- 8 - 13 yrs ( 11 yrs )
- Usually the first sign
-
PUBIC HAIR (Pubarche)
- 9 - 13 yrs
- 1st Pubertal Sign in 25%
-
AXILLARY HAIR (Adrenarche)
- 9.5 - 15 yrs
- May fllow Menarche
-
MENSTRUATION (Menarche)
- 10 - 16 yrs ( 13 yrs )
4
Q
Endocrine Changes in Puberty
- …-…-… synchrony – established in … life
- Until … – neural mechanisms suppress … release
- At …-… yrs – pulsatile nocturnal … release
A
- H-P-G synchrony – established in fetal life
- Until puberty – neural mechanisms suppress GnRH release
- At 6-9 yrs – pulsatile nocturnal GnRH release
5
Q
Endocrine Changes in Puberty
- Pulsatile … release (nocturnal) every … - … min - 6 to 9 years
- increased … leads to increased … and increased …
- …/… become sensitized to the effects of these
- Final phase: development of …/… feedback mechanism
- … stimulates the adrenals – … & … hair
A
- Pulsatile GnRH release (nocturnal) every 90-120 min - 6 to 9 y
- increased GnRH leads to increased FSH and increased 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
6
Q
Testes
- Production of … (…)
- … cells under FSH control
- Production of … (Testosterone)
- … cells under LH control
- …% from testes, …% from adrenals
- Testosterone in blood – converted to … in the target organs
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
- Testosterone in blood – converted to DHT in the target organs
7
Q
The Ovarian Cycle
- … phase
- Initially E rises (…) with LH surge in …
- … occurs
- … phase
- … feedback after ovulation
- No further … in the same cycle
A
- Follicular phase
- Initially E rises (FSH) with LH surge in mid cycle
- Ovulation occurs
- Luteal phase
- Negative feedback after ovulation
- No further ovulation in the same cycle
8
Q
What is this showing?
A
Endometrial cycle
9
Q
Age of Menarche
- Related to general health, genetic and nutritional factors
- Mean age is … at a rate of … months per decade
- Mean age in 1840 = … y; 1990 = … y
- One in … girls now reaches menarche while at primary school
- Body … and % … is also important
- Mean weight at menarche is …kg
- …-…% fat
- …, patients with … – late onset
A
- Related to general health, genetic and nutritional factors
- Mean age is falling at a rate of 4 months per decade
- Mean age in 1840 = 16.5 y; 1990 = 12.8 y
- One in 8 girls now reaches menarche while at primary school
-
Body weight and % fat is also important
- Mean weight at menarche is 47.8kg
- 16-24% fat
- Athletes, patients with anorexia – late onset
10
Q
Adrenarche
- … … – responsible for axillary and pubic hair
- … stimulates zona … of adrenal cortex
- DHEAS & Androstenedione
- Girls – starts by …, adequate levels by …
- Boys – starts by …, adequate levels by …
A
- Adrenal androgens – responsible for axillary and pubic hair
- ACTH stimulates zona reticularis of adrenal cortex
- DHEAS & Androstenedione
- Girls – starts by 6, adequate levels by 8
- Boys – starts by 8, adequate levels by 10
11
Q
Define Adrenarche
- Adrenarche refers to the time during puberty when the adrenal glands increase their production and secretion of adrenal …
- Plasma concentrations of dehydroepiandrosterone (…) and DHEA-sulfate(s), the most important adrenal androgens, begin to increase in children by approximately … to …years.
- However, the signs of adrenarche, such as … and … … development, a…, and body …, do not typically occur until … to ….
A
- Adrenarche refers to the time during puberty when the adrenal glands increase their production and secretion of adrenal androgens. Plasma concentrations of dehydroepiandrosterone (DHEA) and DHEA-sulfate(s), the most important adrenal androgens, begin to increase in children by approximately 6 to 8 years. However, the signs of adrenarche, such as pubic and axillary hair development, acne, and body odor, do not typically occur until early to midpuberty.
12
Q
Chronological Order of Puberty - Girls
- … ….
- … development
- … hair
- … hair
- …
A
- Growth spurt
- Breast development
- Pubic hair
- Axillary hair
- Menarche
13
Q
Chronological Order of Puberty - Boys
- … volume
- … length
- … hair
- … …
- … / … hair
- … voice
A
- Testicular volume
- Penile length
- Pubic hair
- Growth spurt
- Axillary / Facial hair
- Deep voice
14
Q
For each row, what is the subtitle?
A
- Beginning of puberty
- Growth Spurt
- Years of Puberty
- Menarche/Voice Deepening
15
Q
Disorders of Puberty - Early or Precocious
- Girls – under … yrs
- Boys – under … yrs
A
- Girls – under 8 yrs
- Boys – under 9 yrs
19
Q
What is the Diagnosis?
-
Emileigh, 14 months
- Blood clots in nappy
- Bilat breast buds
- Ht & Wt >97th centile
- LH 2.2, FSH 3.2,
- 17β estradiol 432
- Uterus – enlarged
- Bone age – 2.8 yrs
- MRI scan shown
A
- Hypothalamic Hamartoma - premature true puberty - LH and FSH should be undetectable, uterus enlarged, blood clots in nappy, bones advanced (oestrogen), Breast buds
24
Q
- Congenital adrenal hyperplasia (CAH) is a group of autosomal … disorders characterized by impaired … synthesis.
- It results from the deficiency of one of the … enzymes required for the synthesis of … in the adrenal ….
A
- Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders characterized by impaired cortisol synthesis.
- It results from the deficiency of one of the five enzymes required for the synthesis of cortisol in the adrenal cortex.
25
Q
This is showing … biosynthesis
A
Steroid biosynthesis
29
Q
What is the diagnosis?
- Steven, 16 yrs
- No pubertal progress
- Learning difficulties
- Tall, 98th centile
- PH-2, G-2, TV-6ml
- LH 12, FSH 16, T 40
- Bone age – 14.5 yrs
A
Klinefelter Syndrome
30
Q
Klinefelter Syndrome
- 1 in … … infants
- 47 … / Multiple …
- … problems
- … deficiency
- …spermia / …
- (Micro … -> Sex change)
- Lifelong … replacement therapy
A
- 1 in 1000 male infants
- 47 XXY / Multiple X
- Behavioural problems
- Androgen deficiency
- Azoospermia / Infertility
- (Micro genitalia -> Sex change)
- Lifelong testosterone replacement therapy
31
Q
What is the diagnosis?
- Rosie, 12 yrs
- Short Stature
- No pubertal onset
- Recurrent ear infections
- Increased carrying angle
- Widely spaced nipples
- LH 56, FSH 95,
- 17β estradiol 45
- Karyotype
A
Turner Syndrome
32
Q
Turner Syndrome
- 1 in … live … births
- Triad - … stature, … gonads, primary …
- … features – Webbing of neck, cubitus valgus
- … of aorta, horse shoe …
- Early clue - L…
- Surprisingly … !!!
- Turner …
A
- 1 in 2000 live female births
- Triad - Short stature, streak gonads, primary amenorrhoea
- Dysmorphic features – Webbing of neck, cubitus valgus
- Coarctation of aorta, horse shoe kidneys
- Early clue - Lymphedema
- Surprisingly normal!!!
- Turner Mosaic
