Puberty Flashcards by Neil Srivastava

Define puberty

Describe the physiological, morphological and behavioural changes as the gonads switch from infantiles to adult forms

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What is the first sign of girls going through puberty

Menarche (first menstrual bleeding)

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What is the first sign of puberty in boys

First ejaculation, often nocturnal

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What hormone regulates the growth of female and breast genitalia

Ovarian oestrogen

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What hormones control public and axillary hair

Ovarian and adrenal androgens

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What hormones control the development of external genitalis and pubic hair growth + enlargement of larynx and laryngeal muscles (voice deepening)

Tetsicular androgens

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Describe the tanner stages of development for males

Stage 1:
No pubic hair
Testicular length: <2.5 cm
Testicular volume: <3.0 mL

Stage 2:
Sparse growth of curly pubic hair at base of penis
Testes > 3mL
Scrotum thinning and reddening

Stage 3:
Thicker, curlier hair spreads to mons pubis
Growth of penis in width and length: further growth of testes

Stage 4:
Adult-type hair, not spread to medial surfaces of the thigh
Penis further enlarged; testes larger, darker scrotal skin colour

Stage 5:
Adult-type hair spread to medial surface of thighs
Genital adult size and shape

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Describe the tanner stages of development for females

Stage 1:
Prepubertal: No pubic hair
Elevation of papilla only
Stage 2: Sparse growth of long, straight minimally pigmented, mainly on labia
Breast bud palpable: enlargement of areola
Stage 3: Darker, coarser hair spreading over mons pubis
Further enlargement of breast and areola with no separation of contours

Stage 4:
Thick adult-type hair, not yet spread to medial surface of thighs
Projection of areola and papilla to form secondary mound above level of breast

Stage 5: Hair adult-type and distributed in classic inverse triangle
Adult contour breast with projection of papilla only

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How long does breast development take

3 years

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3 effects of oestrogen on the breast

Ductal proliferation
Site specific adipose deposition
Enlargement of the areola and nipple

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What three other hormones than oestrogen are involved in breast development

Prolactin
Glucocorticoids
Insulin

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How does the corpus:cervix ration change from prepubertal to pubertal

From 1:2 to 2:1

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How does the shape of the uterus change from prepubertal to pubertal

Tubular shape to pear shape

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Length change of the uterus

From 2-3 cm to 5-8cm

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How does the volume of the uterus change

0.4-1.6 ml to 3-15ml

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How does the endometrium change in the uterus

From single layer of cuboidal cells it increases in thickness

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What three things does a doctor look out for in a pelvic ultrasound to ensure pubic development is occurring

Are the Mullein structures present
Morphology of the uterus
Morphology of the ovaries

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What is the vagina lined by prepubertally

Thin columnar epithelium

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What is the vagina lined by post puberty

Thickening of the epithelium - stratified squamous epithelium formation

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How does the pH in the vagina change

pH neutral to 3.8

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What happens to the length of the vagina

3.5cm to 8cm

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How does oestrogen effect the maturation of external genitalia

Labia majora and minor increase in size and thickness
Rogation and change in colour of major
Hymen Thickens
Clitoris enlarged
Vestibular glands begin secretion

What is precocious puberty

Onset of secondary sexual characteristics before 8 (girls) and 9(boys)

What is delayed puberty

Absence of secondary sexual characteristics by 14 (girls) and 16 (boys)

Complications of delayed puberty

Reduced peak bone mass and osteoporosis

Where is inhibit produced

Females - pituitary gland, corpus luteum Males - Sertoli cells

Role of inhibin

Surpresses FSH

What inhibits inhibin

GnRH (enhanced by insulin-like growth factor-1)

How is FSH and LH secretion regulated

Circadian rhythms (pulse like)

When during the day is LH produced during early stages of puberty

Sleep

When is LH produced in late puberty

During the day

What is the hypothalamic maturation hypothesis

1. Puberty only requires increased hypothalamic GnRH 2. Emphasises direct link in CNA and pituitary/hypothalamic GnRH neutrons 3. Supporting evidence from rhesus macaque

Role of Kisspeptin

Stimulates primary puberty by releasing GnRH at the hypothalamus

What happens to the level of glutamate and kisspeptin at the start of puberty

Increased

What levels decrease at the start of puberty

Secretions of GABA and opioidergic neutrons (decreases inhibitory tones)

What is Adrenarche

Maturational process of adrenal gland

What happens during adrenarche

Developmental process where a specialised subset of cells arises forming the androgen-producing zona reticularis

What happens to the levels of hormones produced in adrenal glands during adrenarche

Increased DHEA, DHEA-S

Signs of adrenarche

Body odour Oily Skin Mild Acne Axillary hair

What is Pubarche

Result of androgen action (andrenarche) on the pilosebaceous unit transforming vellus hair into terminal hair in hair-growth prone parts of the skin

Name the g-couples receptor that kisspeptin binds o

GPR54

How common is precocious puberty

1 in 5,000

What sex is precocious puberty most common in

90% of females

What should we rule out before suspecting precocious puberty

Ruling out brain tumour

What is precocious pseudo puberty

Secondary sexual development induced by sex steroids from abnormal sources (adrenal glands)

How do we differentiate between Precocious puberty and precocious pseudo puberty

LH:FSH ratio > 1 - precocious puberty LH:FSH < 1 - precocious pseudo puberty

How is precocious puberty treated

GnRH super-agonist to suppress pulsatility of GnRH secretion

What are the causes of precocious puberty (GnRH dependant)

1. Idiopathic precocious puberty 2. CNS tumours 3. CNS disorders 4. Secondary central precocious puberty 5. Psychosocial

What are the causes of precocious pseudo-puberty

1. Increased androgen secretion 2. Gonadotropin secreting tumours 3. McCune-Albright Syndrome 4. Ovarian cyst 5. Oestrogen secreting neoplasm 6. Iatrogenic or exogenous sex hormones

What 3 causes are there of delayed puberty

1. Delayed activation of the hypothalamic pulse generator 2. Hypogonadotrophic hypogonadism 3. Hypergonadotrophic hypogonadism

How does delay in puberty effect repodocution and bone mass

Reproduction defects Reduced peak bone mass

What are indications for delayed puberty in girls

1. Lack of breast development by 13 2. More than 5 years between breast development and Menarche 3. Lackof pubic hair by 14 4. Absent menarche by 15-16

What are indications for delayed puberty in boys

1. Lack of testicular enlargement by 14 2. Lack of pubic hair by 15 3. More than 5 years to complete genital enlargement