4.2: Puberty and Menopause

Question 1

When are the primary sexual characteristics developed and what are they?

Answer 1

Before birth: ducts, external genitalia, ovaries, testis

Question 2

When are secondary sexual characteristics developed and what are they?

Answer 2

Puberty: gamete production, behavioural changes

Question 3

What is the specific sequencing of events that occurs at puberty called? Which gender begins and ends puberty earlier?

Answer 3

The Tanner staging, females tend to begin and end earlier

Question 4

What are the 5 stages of the ‘Tanner staging’?

Answer 4

1. Hormone release but no physical changes
2. First physical changes: girls start breasts, boys undergo testes and scrotum enlargement
3. Growth spurt, continued physical changes; girls develop fat around hips, boys have voice cracks and nocturnal ejaculations (but they still aren’t fertile until…)
4. Key functional events: girls - first period, boys - spermatogenesis (now fertile)
5. Adult physical appearance and function: girls have regular periods/ovulation, boys have facial hair and musculature

Question 5

What is the age of puberty onset in females? List five of the overlapping stages that occur

Answer 5

Ages 8-13

1. breast bud (thelarche)
2. pubic hair growth (adrenarche)
3. growth spurt
4. onset of menstrual cycles (menarche)
5. continued pubic hair and breast growth

Question 6

Describe the five stages of breast development

Answer 6

1. No glandular breast tissue palpable
2. Breast bud palpable under areola
3. Breast tissue palpable outside areola
4. Areola elevated above contour of breast
5. Areola mound recedes into single breast contour with hyperpigmentation, nipple protrusion, etc

Question 7

What is the age of puberty onset in males? List five of the overlapping stages that occur

How many stages are there in male genital development and what is primarily happening?

Answer 7

Age: 9-14

1. genital development begins (testes before penis)
2. Pubic hair
3. growth spurt
4. spermatogenesis begins
5. genitalia and pubic hair continue to develop

5 stages in male genital development; where testis/scrotum continue to grow

Question 8

Why are males generally taller than females?

Answer 8

Female growth spurts are earlier and shorter (partly because they have more estrogen which stimulates fusion at the epiphyseal plate)

Men are taller as their growth spurt is later, longer and at a slightly higher growth rate

Question 9

What happens on a cellular level during a ‘growth spurt’? What terminates it?

Answer 9

Proliferation of chondrocytes at the end of long bones, terminated by the fusion of the epiphyseal plates controlled by estrogen (in both sexes)

Question 10

Can the reproductive system work before puberty?

Answer 10

Yes, it’s just not being triggered since hormonal levels are low due to low GnRH secretions

Question 11

What causes precocious puberty?

How might you treat delayed puberty?

Answer 11

Precocious: GnRH secretion activated earlier than normal (can have other influences on the hypothalamus, e.g; weight)

Delayed: provide exogenous pulsed infusions of GnRH

Question 12

How does leptin influence puberty? At what weight in females is menarche and male/female growth spurts effected?

Answer 12

Leptin (released by fat cells) stimulates the Kisspeptin neuron which stimulates GnRH

47 Kg is necessary for menarche in females

Growth spurts:
55kg needed in males, 30kg in females

Question 13

How does melatonin affect puberty and what influences it? (include one specific type of tumour)

Answer 13

Stimulates the Kisspectin neuron

Melatonin is influenced by changes in day length and is more sensitive to light in prepubertal years (light resets the circadian rhythm and inhibits its synthesis), a pineal tumour can also initiate early puberty (the pineal gland makes melatonin)

Question 14

List three major neuron signals that influence the production of GnRH

Answer 14

1. Kisspeptin neuropeptide
2. Glutamate
3. GABA downregulation

Question 15

What are three genetic predispositions to undergoing earlier puberty in girls?

Answer 15

1. African American girls (earlier than Caucasians)
2. Early-onset of puberty in the mother
3. Mutations in genes for the major neuron signals or their receptors

Question 16

At what age is ‘precocious puberty’ classified, which gender is it more common in and which gender is it more likely to be pathological? List three general causes

Answer 16

Classed as signs of puberty before 8 in females and 9 in males, more common in girls and more likely to be pathological in boys

Cause often unknown but can be due to

1. neurological issues (pineal tumours, meningitis)
2. Uncontrolled gonadotrophin or steroid secretions
3. Genetics

Question 17

How might you treat precocious puberty?

Answer 17

Blocking gonadotrophin release from the pituitary

Question 18

What are the signs of delayed puberty? Which gender is it more common in? List 3 general possible causes

Answer 18

Signs: no testicular development in boys aged 14, no breast development in girls age 13 OR no menarche by age 15

More common in boys

Cause often unknown but can be…

1. linked to malnutrition and chronic illness
2. Issues with gonads, thyroid or pituitary
3. Genetic conditions (e.g androgen sensitivity, Klinefelter’s)

Question 19

What happens on a hormonal level prior to puberty?

Answer 19

1. A rise in pulsatile GnRH secretion (initially at night)

2. Followed by a steady rise in FSH and LH

Question 20

List the hormones involved in the following landmarks of puberty…

a) pubic and axillary hair
b) genital development
c) breast development
d) gamete development
e) growth spurt
f) larynx and laryngeal muscle development in males

Answer 20

a) adrenal androgens in females, androgens in males
b) testosterone, estrogen
c) estrogen
d) FSH, LH, gonadal steroids
e) GH and steroids in both sexes, (and estrogen closes the epiphyses)
f) Testosterone

Question 21

What happens to the menstrual cycle in the pre-menopause stage and what age does this typically begin?

Answer 21

Begins typically at age 40:

1. Follicular phase shortens so ovulation is early or absent
2. Less estrogen is secreted: So LH and FSH levels rise (reduced feedback)
3. Reduced fertility

Question 22

What marks the start of menopause and what is the average age this occurs?

Answer 22

Marked by ceasing the menstrual cycles, averagely ~50

Question 23

What happens hormonally in menopause and why?

Answer 23

Estrogen levels fall dramatically (not being produced by ovarian follicles as the follicle supply is near exhausted), so FSH and LH levels rise (FSH rises more dramatically)

Question 24

Name three general common symptoms of menopause and 4 symptoms specifically involving reproductive tissue

Answer 24

Symptoms:

1. Vascular changes (hot flushes)
2. Changes in skin
3. Changes in bladder

On Repro tissue:

1. Thinning of cervix
2. Vaginal rugae lost
3. Uterus: endometrium regresses and myometrium shrinks
4. Involution of some breast tissue

Question 25

What happens to bone mass during menopause?

Answer 25

Less estrogen increases osteoclast activity (can lead to type 2 osteoporosis) and greater risk of fractures later in life

Question 26

What defines post menopause?

Answer 26

No period for 12 consecutive months

Question 27

What is HRT, why is it used and how can it be given?

Answer 27

Hormone replacement therapy: Estrogen given (orally or topically) to relieve symptoms and limit osteoporosis (although not advised for first line protection)

Question 28

What happens at the end of reproductive life in males?

Answer 28

Gradual decline in fertility: semen volume, motility, quantity and quality but sperm production still continues throughout life

Question 29

How can the puberty process be tested?

Answer 29

Can use hormones like estrogen to test for puberty progress