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Lily BRS Endo > Sex Hormones During Life > Flashcards

Sex Hormones During Life Flashcards

1
Q

What is the definition of puberty?

A

Maturation of reproductive organs

Production of sex steroids

Develop secondary sexual characteristics

Attain capability to reproduce

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2
Q

How is progression through puberty measured?

A

Tanner staging

Thelarche- girls - beast development

Testicular volume - boys

Pubarche - pubic hair - both (this is really cause by adrenal androgen production but it goes along with puberty)

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3
Q

What are the secondary sexual characteristics of girls? And order?

A

Caused by oestradiol

Breast development

Hair growth (public, axillary)

Sweat gland composition- skin oiliness/ acne

Changes to external genetalia

First breast, then growth spurt, then pubic hair. Finally a little bit later menarche

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4
Q

What are the secondary sexual character of boys? And order?

A

Caused by testosterone

Deepening of voice

Hair growth (pubic then axillary, facial)

Sweat gland composition - oiliness/acne

Changes to external genetalia

First testicular volume, then growth spurt, then pubic hair, finally spermarche

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5
Q

What are the ages of puberty?

A

Girls: 8-14

Boys: 9-14

Precocious puberty is more common in girls

Delayed puberty is more common in boys

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6
Q

What are the hormone changes during puberty?

A

ADRENRCHE

Girls: large increase in DHEA

Boys: smaller increase in DHEA

GONADARCHE

Girls: large increase in oestradiol also a large increase in FSH

Boys: large increase in testosterone also a small increase in LH

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7
Q

How does GnRH secretion change with puberty?

A

In childhood the HPG axis is quiesced

Around puberty there is increased nocturnal GnRH pulsatility

At adulthood there is normal pulsatile GnRH secretion

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8
Q

What is mini puberty?

A

In a foetus there are high levels of GnRH

This causes testicular descent, penile length, Sertoli cell maturation and behavioural effects

But this is then quiesced until actual puberty

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9
Q

What is menarche?

A

The start of the menstrual cycle

Occurs ~2.3 years after thelarche, and soon after peak height velocity (growth spurt)

The mean age of onset is 12.7 years but it ranges from 10.7 - 16.1

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10
Q

What are primary and secondary amenorrhoea?

A

Primary: when you haven’t got your period by 16 tears old

Secondary: when you have it but then lose it for a period of 3-6 months

Most common cause of secondary amenorrhoea is pregnancy

There is also oligomenorrhoe - irregular or infrequent periods

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11
Q

What are the three stages of the menstrual cycle?

A

Follicular

Ovulation

Luteal

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12
Q

What happens during the follicular phase of the menstrual cycle?

A
  1. FSH levels rise
  2. 2-3 follicles start to grow
  3. These produce E2 and inhibin B
  4. These reduce FSH by negative feedback
  5. This restricts the “FSH” windows so that the non dominant follicules undergo atresia
  6. A dominant “graafin” follicular emerges
  7. E2 continues to increase
  8. There is a switch to positive feedback on LH due to high E2
  9. This induces a leutenising hormone surge
  10. Causes ovulation n
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13
Q

What happens in the menstrual cycle after ovulation?

A

The follicule develops into the corpus leuteum which releases progesterone and oestradiol

Without presence of a fertilised egg, these levels will drop back down by day 28

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14
Q

What is the uterine cycle?

A

How the endometrium changes during the menstrual cycle

Menstrual phase: bleeding. Layer is shed

Proliferative phase: endometrial lining regrows. New epithelial cells and gland proliferation. Increase in storms and arterioles

Secretory phase: transformation to be receptive for implantation. Increased volume of stromal cells, thick spongy lining. Cork screw shaped glands secreting glycogen, coiling and lengthening of spiral arteries

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15
Q

How does the presence of an embryo affect the menstrual cycle?

A

During the luteal phase it will secrete beta hCG

This acts in LH receptors on the corpus leuteum, stimulating it to keep releasing progesterone

As progesterone levels don’t drop, the endometrium is not shed for the next cycle

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16
Q

What happens if GnRH secretion isn’t pulsatile?

A

This decreases LH and FSH secretion

17
Q

How does GnRH pulsatility change during the menstrual cycle?

A

Follicular phase: pulse every 90-120 mins

Luteal phase: pulse every 180-240 mins

18
Q

What is hypogonadism?

A

Decreased oestrogen in a woman

Decreased testosterone in a man

19
Q

What is primary hypogonasism?

A

Low oestradiol (E2)/ testosterone

But high LH/FSH due to reduced negative feedback to the hypothalamus and pituitary

The problem is in the gonads

In men this may be caused by infection (mumps), trauma, cancer of the testes

In women the main cause is menopause (this also has low inhibin)

20
Q

What is secondary hypogonadism?

A

Low E2/ testosterone

But also low (or normal) LH/FSH

This is due to a lack of functioning negative feedback

If there are sex hormones the levels of gonadotrophs should deffo be raised, not normal

The problem is in the hypothalamus or pituitary

May be caused by a pituitary tumour or high prolactin

21
Q

What are the symptoms of menopause?

A

Due to a lack of oestradiol (occurs at ages 41-55)

Skin dryness/ hair thinning

Hot flushes, sweating, sleep disturbance

Mood disturbance

Osteoperosis (E2 stimulates osteoblasts)

Sexual dysfunction (vaginal dryness, decreased libido)

Weight gain

Amenorrhoea

Cessation of fertility

Climacteric (irregular periods in years close to menopause)

It can be treated with hormone replacement therapy. Oestrogen stimulates the endometrium (of endometrium is intact add progesterone to prevent hyperplasia or cancer)

22
Q

What are ovarian reserve markers?

A

Such as anti mullerian hormone

This usually peaks in early adult life and is very low at menopause

So by measuring levels of this, you can see how close a person is to menopause and therefore roughly how many eggs they have

23
Q

What is early menopause?

A

Premature ovarian insufficiency (used to be called premature ovarian failure)

Conception can still happen in 20% of people

It can be diagnosed with high FSH levels

Caused by: autoimmune, genetic (fragile X syndrome/ turners), cancer therapy

24
Q

Is there an equivalent of menopause In men?

A

“Andropause”?

Sorta

In some people there is late onset hypogonadism

In which the levels of testosterone in the body slowly fall until they are very old

This happens as you get older as levels of sex hormone binding globulin increase. So there is less free T

25
Q

How is testosterone present/carried in the body?

A

60% is bout to sex hormone binding globulin (SHBG). This is strongly bound and unavailable

38% is bound to albumin. This is weakly bound and “bioavaliable”

2% is free testosterone. This is active

26
Q

When should you measure testosterone levels?

A

In the morning as it has a diurnal rhythm

Also fasting, as T levels can fall with sugar consumption

27
Q

What are some symptoms of testosterone deficiency?

A

Sexual dysfunction (low libido)

Erectile dysfunction (includes loss of early morning erections)

Less hair growth (may need to shave less often)

Low energy levels

Mood disturbance

Body composition (increased fat, reduced muscle mass)

Less spermatogenesis

Osteoperosis

28
Q

What happens to testosterone? (Possible pathways)

A

Testosterone —> oestrogens (by aromatase enzymes)

This is stimulated by age, obesity, alcohol, insulin, ginadotrophins.

It occurs in adipose tissue, adrenal glands, ovaries (granulosa), testes (sertoli), brain bone and skin

Testosterone —> di hydro testosterone (by 5 alpha reductase)

This occurs in the testes (seminal vesicles and epididymis), prostate, skin and scalp, liver

It is a more potent ligand for androgen receptor

Lily BRS Endo (10 decks)

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