Puberty and the HPG axis

Question 1

what is precocious puberty

Answer 1

puberty before the age of 8

Question 2

why might precocious puberty be stimulated by meningitis

Answer 2

as menignitis infers with the pulsating release of GnRH, disrupting the axis

Question 3

will individuals who have had precocious puberty be taller or shorter and why

Answer 3

shorter - as their epiphyseal growth plates will close sooner

Question 4

what scale is used to asses points of puberty

Answer 4

tanner scale

Question 5

define puberty

Answer 5

a stage of human development when sexual maturation and growth are completed and result in the ability to reproduce

Question 6

the secretion of what hormone from the pineal gland assists in puberty

Answer 6

melatonin

Question 7

what role does leptin play in puberty

Answer 7

leptin determines when the child (particularly girls) have enough adipose tissue to sustain reproductive life

Question 8

what is the critical weight for girls to enter puberty

Answer 8

47kg

Question 9

what can cause precocious puberty

Answer 9

Brain injury, hydrocephalus, meningitis, congenital adrenal hyperplasia, pituitary tumour, pineal tumour

Question 10

when does puberty begin in girls

Answer 10

9-13

Question 11

what is aromatase

Answer 11

an enzyme which converts testosterone into oestrogen

Question 12

what causes the closure of epiphyseal growth plates

Answer 12

oestrogen

Question 13

when does puberty start in boys

Answer 13

10-14

Question 14

what does HPG stand for

Answer 14

hypothalamo-pituitary-gonadal axis

Question 15

what hormone is released from the hypothalamus in the HPG axis

Answer 15

GnRH

Question 16

what does GnRG stand for

Answer 16

gonadotrophin releasing hormone

Question 17

what causes the release of GnRH

Answer 17

leptin and photoperiod

Question 18

in what pattern type if GnRH secreted

Answer 18

pulsatile pattern

Question 19

where does GnRH go

Answer 19

to the anterior pituitary gland to stimulate the release of hormones

Question 20

what hormones are released in response to GnRH

Answer 20

luteinising hormone and follicle stimulating hormone

Question 21

how is the HPG axis controlled

Answer 21

though positive and negative feedback

Question 22

when do LH secretions increases

Answer 22

during sleep

Question 23

in males what does LH do

Answer 23

stimulates leading cells to produce testosterone

Question 24

in males what does FSH do

Answer 24

stimulates Sertoli cells to help mature sperm cells and release inhibin

Question 25

what does inhibin do

Answer 25

causes a negative feedback loop to FSH

Question 26

why dos Sertoli cells have tight junctions

Answer 26

to prevent sperm from entering the blood stream as they have different antigens so are seen as foreign

Question 27

in females where does LH go

Answer 27

goes to the theca interna cells

Question 28

in females where does FSH go

Answer 28

granulose cells

Question 29

what negative feedback occurs in the female HPG axis

Answer 29

normal oestrogen levels give negative feedback to the hypothalamus
inhibin gives negative feedback to FSH

Question 30

what cells in females produce inhibin

Answer 30

granulose cells

Question 31

describe the positive feedback occurring in the female HPG axis

Answer 31

high levels of oestrogen send positive feedback signals to the hypothalamus causing a LH surge