PBL 1

Question 1

when in intrauterine life does GnRH secretion begin?

Answer 1

4th week of intrauterine life

Question 2

when in intrauterine life doe FSH and LH begin being secreted?

Answer 2

week 10-12

Question 3

what causes the pulsatile secretion of GnRH?

Answer 3

the tonic centre

akak pulse generator

Question 4

at what age does the pulsatile secretion of GnRH begin in males and females?

Answer 4

12 in f and 14 in m

Question 5

describe how GnRH secretion and sensitivity changes during puberty

Answer 5

at first, pulses only occur at night but as puberty advances pulses begin to occur in the day and overtime they become more frequent. the GnRH receptors on anterior pituitary also become more sensitive so we get ;larger releases of Lh and FSH

Question 6

how do LH and FSH secretions in puberty affect cells in the testis?

Answer 6

leydig cells respond to LH by producing testosterone whilst Sertoli cells respond to FSH by kickstarting sperm production

Question 7

how do LH and FSH secretions in puberty affect cells in the ovaries?

Answer 7

theca cells respond to LH by producing androstenedione whilst granulosa cells respond to FSH by converting androstenedione to oestrogen and progesterone

Question 8

what is the surge centre and who has it?

Answer 8

an area in the hypothalamus that causes FSH and LH levels to vary over the menstrual period
only women

Question 9

what do granulosa cells produce more of in the follicular phase and the luteal phase?

Answer 9

follicular phase - oestrogen

luteal phase - progesterone

Question 10

when are FSH levels higher than LH?

Answer 10

childhood

Question 11

what are primary sex characteristics?

Answer 11

reproductive organs

Question 12

what are secondary sex characteristics?

Answer 12

any sex specific physical characteristic that is not directly involved in reproduction e.g. breasts, facial hair

Question 13

outline Tanner stage 1

Answer 13

1. pre-pubertal stage -no pubic hair present, males have small penis and testis and females have a flat chest - hypothalamus begins to release GnRH

Question 14

outline Tanner stage 2?

Answer 14

2. soft pubic hair present, males have enlargement of testis and scrotum. Females have breast buds appearing which can be itchy or tender, the uterus also gets larger.
   9-11 in girls and 11 in boys

Question 15

outline Tanner stage 3?

Answer 15

3. coarser pubic hair, hair starts forming under armpits, first signs of acne may appear, highest growth rate of height, penis becomes to enlarge and breast mounds form. boys begin to have wet dreams, voices may crack, muscles get larger
   12 in girls and 13 in boys

Question 16

outline tanner stage 4?

Answer 16

4. pubic hair begins to cover the pubic area and the penis becomes larger again. breast enlargement continues. girls get first period between 12-14. armpit hair in boys starts to occur around age 4 and deeper voice becomes permenant
   13 in girls
   14 in boys

Question 17

outline tanner stage 5?

Answer 17

5. pubic hair extends to inner thigh, penis and testis enlarge to adult size and female breasts take on adult contour. periods become regular, hips thigh and buttocks fill out in shape, facial hair in boys
   after 15 in girls and boys

Question 18

what is delayed puberty?

Answer 18

described as not beginning progression through the tanner scale by the time 95% of peers have become to sexually mature. in boys this is 14 and in girls this is 13 or periods not begun by 16

Question 19

what are the 3 groupings for causes of delayed puberty?

Answer 19

primary hypogonadism - gonads dont respond to hormones or cells dont produce hormones
secondary hypogonadism - cant produce GnRH, LH or FSH or there is suppression by prolactin/thyroid hormone
constitutional delay - lack of GnRH but is not pathologic

Question 20

what are causes of primary hypogonadism?

Answer 20

radiotherapy, chemotherapy, gonad trauma, Klinefelter syndrome, Turner syndrome

Question 21

why is it called hypergonadotropic hypogonadism?

Answer 21

because there is no rpdocution of sex hormones, there is no feedback inhibition on the hypothalamus which causes Increased LH and FSH secretion

Question 22

what are causes of secondary hypogonadism?

Answer 22

radiotherapy, chemotherapy, gonad trauma, tumour on pituitary or hypothalamus, panhypopituitarism, Kallmann syndrome, obesity, malnutrition, stress, chronic illness, excessive exercise

Question 23

which types of puberty delays can cause infertility?

Answer 23

primary and secondary hypogonadism

Question 24

how is puberty delay diagnosed?

Answer 24

comparing sexual development using Tanner scale, blood tests for hormone levels, detailed medical history

Question 25

how is short stature described?whose height is 2 SD or more below the mean for children or that sex and age.

Answer 25

whose height is 2 SD or more below the mean for children or that sex and age.

Question 26

what are some causes of abnormal stature?

Answer 26

chronic diseases, GH deficiencies, mitochondrial diseases, malnutrition, psychosocial stress

Question 27

what’s the main difference between failure to thrive and problems with growth?

Answer 27

in failure to thrive the weight percentile is less than the height percentile but in growth problems the height percentile is less than weight percentile

Question 28

what androgen do we give to treat short stature?

Answer 28

oxandrolone

Question 29

what are some risks of human growth hormone therapy?

Answer 29

large doses can cause irreversible acromegaly
complications lie heart disease and diabetes
increased insulin resistance
oedema in arms and legs
joint and muscle pain
carpal tunnel syndrome
gynecomastia in men
increased risk of certain cancers