6 Puberty

Question 1

Define puberty.

Answer 1

Preparation for sexual maturity

Question 2

Disorders of which gland can cause early onset (precocious) puberty?

Answer 2

Pineal gland

(eg pineal tumour)

Question 3

Apart from the pineal gland, what other factors will have an effect on the onset of puberty in girls?

Answer 3

• Body weight- critical weight 47kg
• Nutrition
• Leptin (released from adipose tissue)

(low body weight can cause cessation of menstruation)

Question 4

What scale can we use to assess the stages of puberty in boys and girls?

Answer 4

Tanner scale

Question 5

Differentiate between primary and secondary sexual characteristics.

Answer 5

Primary sexual charcateristics:

-sexual characteristics at birth- eg anatomy of internal and external genitalia

Secondary sexual charcateristics:

-characteristics that develop after puberty eg pubic hair, breasts, genital development/enlargement, menstruation

Question 6

When do boys and girls usually start puberty?

Answer 6

Girls: 9-13yrs

Boys: 10-14yrs

Question 7

What is the sequence of events that occurs in females during puberty? (6)

Answer 7

1. Thelarche
   
   1. Breast bud development
2. Pubic hair
   
   1. Begins to grow- Under influence of testosterone
3. Growth spurt
   
   1. Oestrogen levels= important in fusion of epiphyseal plates
   2. Growth hormone triggers growth spurt
4. Menarche
   
   1. Initiation of menstrual cycle
5. Pubic hair
   
   1. Becomes coarser- further anatomical spread
6. Breast development
   
   1. Growth of breast tissue

Question 8

What is the sequence of events that occurs in males during puberty? (6)

Answer 8

1. Genital development
   
   1. Testicular volume enlargement
2. Pubic hair
   
   1. Begins growth- under influence of testosterone
3. Spermatogenesis
   
   1. process begins
4. Growth spurt
   
   1. (later in boys)
   2. Lower levels of oestrogen- taller that girls- epiphyseal growth plates slow to close
5. Genital enlargement
   
   1. Testes and external genitalia increase in size
6. Pubic hair
   
   1. coarser and pattern changes

Question 9

Explain why early onset (precocoius puberty) can cause short stature.

Answer 9

Levels of oestrogen rising earlier

Early fusion of epiphyseal plates

Question 10

Name the hormone which is thought to trigger the start of puberty. Where is it released from and how is it released?

Answer 10

Gonadotrophin releasing hormone (GnRH)

(thought to be triggered by release of leptin)

Produced by hypothalamus

Released from anterior pituitary

Secretion in pulses- tied to internal body clock

Amplitude of pulses increase- esp during sleep

Question 11

What does GnRH cause the release of and what effect do these hormones have?

Answer 11

GnRH- triggers release of LH and FSH (males and females)

From gonadotrophs in anterior pituitary

High levels of LH and FSH stimulate gonads (testes/ovaries) to release androgens and oestrogen - have negative feedback on GnRH

Question 12

Which cells do FSH and LH act on in males?

Answer 12

Question 13

Which cells do FSH and LH act on in females?

Answer 13

Question 14

What does inhibin do and where is it released from

Answer 14

Released from follicles (gametes) which have been stimulated

Has negative feedback on FSH- prevent further sperm production/maturation of more follicles

Question 15

What artery connects the anterior pituitary and the hypothalamus?

Answer 15

Superior hypophyseal artery

Question 16

What roles does leptin have on the body?

Answer 16

• Signals information about energy stores to CNS
• Can accelerate onset of reporductive function
• Can regulate GnRH levels

Question 17

Useful info about stages of puberty- ages:

Answer 17