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Intercal - Advanced molecules, membranes and cells > Endocrine Signalling 3 > Flashcards

Endocrine Signalling 3 Flashcards

1
Q

Whats the difference between autocrine and paracrine

A

Autocrine is to the same cell type and paracrine - different cell type

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2
Q

What is a pheromone

A

Substance that goes into the environment (smells etc)

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3
Q

Are there any human pheromones

A

No robust evidence but believed to be - androstenone

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4
Q

What steroid hormones are produced by the gonads

A

Oestrogens
Androgens (testosterone, DHT etc)
Progesterone

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5
Q

What non-steroid hormones are produced by the gonads

A

Inhibin A and B
Activin
Follistatin

(Growth factors)

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6
Q

What hormone is released by the hypothalamus

A

GnRH

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7
Q

What hormone is produced by the anterior pituitary gland

A

LH
FSH
Prolactin

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8
Q

What hormone is produced by the pineal gland

A

Melatonin

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9
Q

What hormones does the placenta produce

A

hCG
Placental lactogen

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10
Q

How are hormones modulated and why

A

Via desulphation and glucuronidation - allows them to cross the cell membrane.

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11
Q

Give some methods of hormone modulation

A

Sulphation
Glucuronidation
Sex hormone binding globulin
AFP
Serum albumin
Glycosylation
Active transport
Biotransformation in the liver

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12
Q

Explain the hypothalamo-pituitary gonad axis for sex hormones

A

Hypothalamus releases GnRH to AP

AP releases LSH and FH to gonads

Gonads release testosterone, progesterone and oestrogen to target tissues

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13
Q

What is an ultrashort feedback loop

A

Hormones affect cells which secrete them (autocrine)

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14
Q

What is a short feedback loop

A

Releasing hormones (e.g. GHRH on the hypothalamus)

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15
Q

What is a long feedback loop

A

Feedback via the peripheral blood supply (e.g. - GnRH inhibited by sex hormones)

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16
Q

What is photoperiod

A

The change in environment light cycles

17
Q

What hormone is affected by photoperiod

A

Melatonin - high at night

18
Q

What are retinal ganglion cells positive for

A

Melanopsin

19
Q

What does melanopsin do

A

Melanopsin –> retino-hypothalamic tract –> pineal gland –> manipulates melatonin release

20
Q

When do most hormones peak

A

Night time

21
Q

Why is photoperiod important in humans regarding sexual activity

A

The rise in melatonin correlated to a rise in pregnancy - therefore melatonin has link to sexual activity.

22
Q

What are the three stages of sex determination

A

Genetic sex - determine by sperm if XX or XY present
Gonadal sex - uterus or testes grow etc
Phenotypic sex - looks male/female

23
Q

What is SRY

A

Sex determining region - found on Y chromosome as testosterone pushes testes growth

24
Q

What are the general stages of sex determination

A

Bipotential gonad - germ cells migrate to gonadal precursor tissue near kidneys

Primary sexual differentiation - reproductive tissues and brain sex - no surge area in males (labour)

Secondary sexual differentiation - secondary sexual characteristics

25
Q

Why does guevedoces help us understand DHT

A

Guevedoces is children in the dominican republic which dont grow penises until puberty as have a deficiency in 5-alpha-reductase (testosterone to DHT)

Boys appear female but get second surge of testosterone in puberty and grow secondary characteristics.

26
Q

What did the guevedoces help achieve

A

Finasteride - 5 alpha reductase inhibitors

27
Q

What does anti-mularian hormone and testosterone do to the mesonephric duct and paramesonephric duct during sexual development (MALES)

A

Mesonephric duct - becomes wolffian duct and epididymis

Paramesonephric duct degenerates

28
Q

What does no anti-mularian hormone and no testosterone do to the mesonephric duct and paramesonephric duct during sexual development (FEMALES)

A

Mesonephric duct degenerates

Paramesonephric duct - oviducts, uterus and cervix

29
Q

How do XY chromosomes make a male

A

TDF/SRY on Y chromosome - testes develop –> seritoli cells secrete AMH –> Degeneration of paramesonephric duct and leydig cells differentation –> leydig cells make testosterone and dihydrotestosterone –> male duct system, penis, scrotum and accessory sex glands

30
Q

How does no Y chromosome make a female

A

No TDF/SRY –> Ovaries develop and no AMH produced –> paramesonephric duct becomes oviducts, uterus and cervix

31
Q

What is the masculination programming window

A

Important time which is testosterone dependenent between 10-12 weeks gestation.

Important for male gonad development

32
Q

What two conditions are important regarding poor testosterone production

A

Crpytorchidism
Hypospadius

33
Q

What three hormones are needed for production of female oocytes

A

E2
FSH
Inhibin

34
Q

How many oocytes do females have at week 22 gestation compared to birth

A

7 million –> 2 million

35
Q

When is LH needed

A

Late stages of oocyte development, takes over from FSH

36
Q

Why might a gene have different hormone response elements

WIDER READING - Pg973 of molecular cell biology krieger et al

A

Allows versatile control over the rate of transcription of a specific gene

37
Q

What did melatonin injecctions show in rats regarding sexual activity

WIDER READING - Drago 2000

A

High injections into the amygdala inhibit sexual performance whilst small doses stimulated sexual activity in rats

38
Q

What does melatonin do to erections

WIDER READING - Boxkurt et al 2018

A

Deficiency can cause erectile dysfunction

39
Q

What is an indicator for the masculinization programming window

WIDER READING - Welsh et al 2014

A

Anogenital distance - can be indicated for azoospermia, hypospadias and cryptorchidism.

Intercal - Advanced molecules, membranes and cells (31 decks)

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