7.0 Puberty Flashcards Preview

MedST IB: Human Reproduction (HR) > 7.0 Puberty > Flashcards

Flashcards in 7.0 Puberty Deck (39)
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1
Q

What age is average for menarche in females?

A

13yrs old<br></br><br></br>Usually no egg present (anovulatory)

2
Q

What is a sign of male puberty?

A

First ejaculation (often nocturnal)<br></br><br></br>Usually only seminal plasma with no spermatozoa

3
Q

Define gonadarche:

A

Changes dependent on steroid hormones from gonads

4
Q

Define adrenarche:

A

Changes dependent on steroid hormones from adrenal gland

5
Q

What age do girls hit peak growth velocity?<br></br>What age do boys hit peak growth velocity?

A

Girls = 12 yrs<br></br>Boys = 14yrs

6
Q

What explains the height difference between men and women?

A

Boys are older and taller at point of take off.<br></br><br></br>Amount grown during growth sprout is actually the same in males and females

7
Q

Complete the blank:<br></br><br></br>Adult men have _____ times more lean body mass than women.<br></br><br></br>Adult women have _____ times more body fat than men.

A

Adult men have 1.5 times more lean body mass than women.<br></br><br></br>Adult women have 2 times more body fat than men.

8
Q

How long after menarche do females experience their first ovulation?

A

Ranges from months → 2 years

9
Q

When is adult stature reached in females?

A

15

10
Q

When is adult stature reached in males?

A

17

11
Q

What do testicular androgens cause in males?

A

1) Development of genitalia<br></br>2) Body hair<br></br>3) Enlargement of larynx and laryngeal muscles

12
Q

What do ovarian oestrogens cause in females?

A

Development of breast and genitalia

13
Q

What do ovarian and adrenal androgens cause in females?

A

Pubic + auxillary hair

14
Q

When do testes descend from abdomen?

A

7-8th month in utero

15
Q

What hormones control descent of testes?

A

1) Mullerian inhibitory substance (MIS)<br></br>2) Testosterone

16
Q

What directs the pull of testes?

A

Gubernaculum

17
Q

When does spermatogenesis begin?

A

9 yrs

18
Q

When is mature spermatozoa produced?

A

14-15yrs

19
Q

How many ovaries are present at birth?

A

500,000

20
Q

How many ovaries are present at puberty?

A

83,000

21
Q

What are cryptorchid testes?<br></br><br></br>What is the treatment?

A

Testes that fail to descend at birth (3-4% of males)<br></br><br></br>0.8% fail to descend by 1 yr<br></br>0.3% fail to descend by 9yrs (commencement of spermatogenesis)<br></br><br></br>Treatment = surgery or Gonadotrophins/GnRH

22
Q

How much cooler do the testes need to be compared to the body for spermatogenesis?

A

3.1 degrees

23
Q

What are the daily patterns of hormone changes seen during puberty in females?

A

1) Fluctuations<br></br>2) ↑ amplitude (at night then always)

24
Q

How often do hormonal pulses need to be for puberty to occur?

A

1-3 hours

25
Q

What is the first endocrine change to occur in puberty?

A

<b>Dehydroepianosterone</b>

26
Q

Where are the following released from in females?<br></br>Oestradiol<br></br>Oestrone<br></br>Androgens

A

Oestradiol: follicles in ovary<br></br>Oestrone: body fat<br></br>Androgens: adrenal gland

27
Q

What is the source of oestrogens in males?

A

Steroli cells

28
Q

What causes acne?

A

Androgens → ↑ sebum → clogged glands → acne

29
Q

What is the effect of growth hormone during puberty?

A

1) Increases bone and tissue growth (along with androgens)<br></br>2) Roles in protein synthesis and glucose homeostasis

30
Q

What is the effect of thyroid hormone during puberty?

A

↑ metabolic rate

31
Q

What is onset of puberty associated with

A

<b>GnRH pulsing</b><br></br><br></br>(other components of system = <b>Neurokinin B</b> + <b>Kisspeptin</b>)

32
Q

What weight does puberty start for girls?

A

47Kg

33
Q

What weight does puberty start for boys?

A

55Kg

34
Q

What hormone may play a role in explaining the nutritional cause for pubertal increase in GnRH?

A

Leptin

35
Q

What is the effect of Melatonin and pineal secretions on puberty?

A

Inhibit reproductive function

36
Q

Comment on blind/deaf childrens puberty age:

A

Usually earlier (?sensory deprivation → quicker puberty?)

37
Q

Effect of pullutants on puberty?

A

Xenoestrogens (plastic industry) → earlier puberty<br></br><br></br>Other pullutants delay male puberty

38
Q

Effect of climate/altitude?

A

↑ altitude → delayed puberty

39
Q

Effect of genetics on puberty?

A

Black girls hit puberty before white girls