Puberty Flashcards Preview

ESA 4 - Reproductive System > Puberty > Flashcards

Flashcards in Puberty Deck (84):
1

Define thelarche

The development of breasts

2

Define puberache

Development of axillary and pubic hair

3

Define menarche

The first menstrual period

4

Define adrenarche

The onset of an increase in secretion of androgens

5

What is puberty? 

The stage of human development when sexual maturation and growth are completed. and result in an ability to reproduce 

6

When are primary sexual characeristics established? 

Before birth 

7

When is the reproductive system inactive until? 

Puberty

8

What is the onset age of puberty? 

Variable 

9

How does the age of puberty differ between boys and girls 

Girls begin and end puberty before boys

10

Is the order of events in puberty consistent or variable? 

Consistent, they happen in a recognised pattern 

11

What does puberty consist of? 

  • Accelerated somatic growth
  • Maturation of primary sexual characteristics
  • Apperance of secondary sexual characteristics
  • Menstruation and spermatogenesis behin

 

12

What does the accelerated growth phase in puberty follow?

The linear growth phase before puberty 

13

What primary sexual characteristics develop in puberty? 

Gonads and genitals

14

What secondary sexual characteristics appear at puberty? 

  • Pubic and axillary hair
  • Female breast development
  • Male voice changes

 

15

When does the menstruation and spermatogenesis begin? 

At the end of puberty

16

What is puberty initated by? 

The brain

17

What is the onset of puberty associated with? 

Steady rise in FSH and LH secretion, due to a rise in GnRH secretion

18

Can the parts of the reproductive system work before the normal age of puberty? 

Most can, but don't because hormone levels are too low

19

In which sex does the growth spurt occur? 

Both 

20

How does the growth spurt differ between males and females? 

Happens earlier, and results in shorter in females

21

Why are men taller? 

Because the growth spurt is longer and slightly faster, and the linear phase is longer, so taller when start to spurt

22

What does the growth spurt depend on? 

Growth hormones and steriods

23

How is the growth spurt ended? 

In epiphyseal fusion 

24

What closes epiphyseal growth plates in girls? 

Oestrogen

25

What can be observed by the fusing of the growth plates? 

The measureable end of puberty

26

How has the timing of puberty changed? 

In Western countries, puberty is now much earlier. 

The average age of menarche was 17 in 1800, now <13 years

27

What is the change in the age of onset of puberty due to? 

Changes in nutrition and weight

28

What is the critical weight for the onset of puberty in females? 

47kg

29

What is happening to the average age of body weight at onset of menarche?

It is staying the same

30

What happens in a female if there is significant weight loss? 

The reproductive cycle ceases 

31

In what situations may primary amenorrhea due to low body weight occur? 

  • Malnutrition 
  • Lean female athletes

 

32

In whom is the 'body fat' set point very noticable? 

In girls with fluctating body weight due to anorexia nervosa

33

What may be involved in puberty signalling? 

Leptins

34

What is true of many species, regarding puberty and menarche? 

Breeding is seasonal, and so there is a new 'puberty' each year

35

What is the new puberty each year in some species triggered by? 

Changes in day length

36

What gland is involved in the 'new puberty' in some species? 

Pineal gland

37

What plays an important part in the pineal gland? 

Secretion of melatonin

38

What evidence shows the involvement of the pineal gland in human puberty? 

Pineal tumours can influence puberty in humans

39

What comes first in puberty, physical or hormonal changes? 

Hormonal

40

What causes the hormonal changes in the onset of puberty? 

Increased stimulation of the hypothalamo-pituitary-gonadal axis, and thus gradual activation of GnRH 

41

What does the gradual activation of GnRH at the onset of puberty cause? 

Increases frequency and amplitude of LH pulses

42

What happens in puberty once levels of gonadotrophins are high enough?

They stimulate the secretion of sexual steroids (oestrogens and androgens)

43

What extragonadal hormone changes occur at the onset of puberty? 

Elevation of IGF-I and adrenal steroids

44

Draw a diagram illustrating the hormone changes that trigger the onset of puberty

45

Where is neuro-kinin B released from? 

The arcuate area of the brain 

46

What happens if there is destructive coding of Kiss 1 neuron arcuate? 

Delayed onset of puberty

47

What happens is there is abnormal positive feedback on Kiss 1 neuron arcuate? 

Early onset of puberty

48

What is the effect of GnRH secretion from the pituitary? 

  • Increases TSH 
  • Increases metabolic rate
  • Promotes tissue growth
  • Increases androgens

49

What is the result of the effect of GN secretion from the pituitary? 

Results in growth spurt

50

What is the result of noctural GnRH pulsatility? 

LH secretion precedes phenotypic changes by several years

51

What does the noctural GnRH pulsatility in pre-pubescent boys suggest? 

Sleep related LH increase stimulates a noctural rise in testesterone 

52

What could the noctural rise in testosterone in adolescent boys account for? 

Some early pubertal changes seen in males

53

What pattern is seen similar to the noctural rise in testerosterone in pre-pubescent females?

Concomitant increase in oestrogen

54

What is true of LH and FSH levels in young children? 

They are insufficient to initiate gonadal function 

55

When do blood levels of LH and FSH increase? 

Between 9-12 years

56

When to levels of LH and FSH increase until? 

They reach levels high enough to initate gonadal development

57

What happens to the pulses of LH and FSH as a child gets older? 

The amplitude of the pulses increases, especially during sleep

58

What are the first phenotypic changes in puberty? 

  • Breast development
  • Testicular enlargement

 

59

What does an increase in LH and FSH lead to in males? 

Spermatogenesis and androgen secretion 

60

Other than the gonads, what else secretes androgen? 

The adrenals

61

What does the secretion of androgens in males lead to? 

  • Sex accessory structures developments, e.g. prostate
  • Male secondary sex characteristics, e.g. facial hair
  • Growth of larynx, leading to the voice breaking

 

62

What induces secondary sex characteristics in females? 

Oestrogen

63

What sexual secondary characteristics does oestrogen induce in females? 

  • Growth of pelvis
  • Deposit of subcutaneous fat
  • Maturation of internal reproductive organs and external genitalia
  • Androgen release by adrenal gland increases

 

64

What does androgen release cause in females? 

  • Growth of pubic hair
  • Growth of bone
  • Increased secretion from sebaceous gland

 

65

How is pubertal development classified? 

According to the Tanner standard

66

How many stages are there on the Tanner scale

5

67

What factors are staged on the Tanner scale in girls? 

  • Breast (B1-5)
  • Pubic hair (Pu1-5)
  • Axillary hair (A1-5)
  • Menarche

68

What are the Tanner stages in girls? 

69

What factors are staged in the Tanner standard in males? 

  • Testicular volume >4ml (Te)
  • Penis enlargement (G1-5)
  • Pubic hair (Pu1-5)
  • Axillary hair (A1-5)
  • Spermarche

70

What are the Tanner stages in boys? 

71

What is the criteria for the pubertal growth acceleration? 

Growth velocity is 2-3 times greater than prepubertal

72

At what age do girls start puberty? 

9-13 years

73

What is the first physical sign of puberty in females? 

B2 (breast development)

74

What is the growth velocity during puberty in females? 

9.0cm/yr (Tanner II-III)

75

What is the duration of puberty in females? 

2.4 years + - 1.1

76

At what age do boys start puberty? 

10-14

77

What is the first sign of puberty in males? 

G2 (testicular volume up to 4ml)

78

What is the growth velocity during puberty in males?

10.3 cm/yr

79

What is the duration of puberty in females? 

3.2 yrs + - 1.8

80

What initates the first ovarian cycle? 

LH surge

81

Is the LH surge usually sufficient to cause ovulation during the first cycle? 

No, can take a couple of years to establish oogenesis

82

What happens once oogenesis is established?

It continues fairly regularly

83

What happens soon after the first ovarian cycle? 

The brain and endocrine systems mature 

84

What happens to oestrogen levels in the blood following the initiation of the first ovarian cycle? 

They increase, due to the growing follicles