Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Week 1 SEM 4 > 2. HYPOTHALAMIC-PITUITARY GONADAL AXIS > Flashcards

2. HYPOTHALAMIC-PITUITARY GONADAL AXIS Flashcards

1
Q

What type of hormones are LH and FSH?

A

Peptide Hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of hormones are oestrogen, progesterone and androgens?

A

Steroid Hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where are receptors for peptide hormones found?

A

Inside the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does kisspeptin do?

A

Controls GnRH release and synthesis- makes it pulsatile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a GnRH analogue?

A

Different peptide structure to GnRH; downregulates HPG axis; can have agonist/antagonist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does a synthetic GnRH analogue do?

A

Stimulates HPG axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is kisspeptin produced?

A

Neurones in the brain- at first kisspeptin is inactive, gets cleaved and then gets activated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do we need to reproduce?

A

sexual intercourse, right gamete number, right chromosome number, fertilise, implant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

At what point do gonads positively feedback to the hypothalamus and anterior pituitary?

A

LH surge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What releases LH and FSH (gonadotrophins)?

A

Anterior Pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do the gonads release in females?

A

Oestrodiol (E2) and Progesterone (P4) (STEROID HORMONES)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What types of hormones do the male gonads release?

A

STEROID HORMONES: Testosterone

PEPTIDE HORMONES: activin and inhibin (negative feedback of FSH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is GnRH secreted from?

A

GnRH hormones in the hypothalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where is GnRH released into?

A

Hypophyseal portal circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does GnRH bind to ?

A

Gonadotroph cells on the anterior pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which hormone can feedback negatively and positively?

A

Oestrogen- only during ovulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the functions of the HPG axis?

A

gamete production in males, growth and development in males and females

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Give an outline of the hypophyseal circulation

A
  1. neuronal kisspeptin neurones act on GnRH neurones
  2. GnRH released into primary plexus
  3. Go into median eminence
  4. Travel via hypophyseal portal vessel to ant pituitary
  5. GnRH bind to gonadotroph cells
  6. LH and FSH release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of hormone is kisspeptin?

A

Peptide hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where is kisspeptin expressed?

A

In arcuate and AVPV nuclei in hypothalamus

21
Q

What receptor does kisspeptin bind to on GnRH

A

GPR54 (aka kiss-1)

22
Q

wHAT Is kisspeptin cleaved from?

A

pro-pro kisspeptin peptide structure

23
Q

What is the largest kisspeptin cleaved form?

A 
kisspeptin 54 (METASTIN)- the biggest one - can be cleaved to form smaller ones kp-14, kp-13, kp-10. KP-54 can cross BBB
All have a C-terminal region that contains an Arg–Phe–NH2 motif characteristic of the RF-amide peptide family, which allows them to fully activate KISS1 receptor.
24
Q

Where are GnRH neurones found?

A

in the parvocellular system

25
Q

What is a GnRH pulse generator?

A

small collection of GnRH neurones- maintain pulsatility, speed and frequency of GnRH pulse generation.

26
Q

What type of peptide is GnRH?

A

Decapeptide= 10 amino acids

27
Q

What is GnRH released with?

A

GAP (GnRH associated protein)- (56 amino acids long) function unknown but maybe to do with prolactin release

28
Q

How often is GnRH released?

A

pulsatile- every 30 to 120 minutes

29
Q

Why is pulsatile release of GnRH important?

A

pulsatile GnRH release= pulsatile LH and FSH release

if GnRH not pulsatile- then no LH/FSH release bc GnRH receptor desensitizes

30
Q

What does rapid GnRH pulse favour?

A

LH release Fast pulses are 30 to 60 mins

31
Q

What does slow GnRH pulse favour?

A

FSH release Slow pulses are 60 to 90mins

32
Q

What does synthetic GnRH do?

A
  1. GnRH binds to the GnRH receptor
  2. signalling in cell is activated
  3. stimulates gonadotrophin synthesis and secretion
  4. GnRH dissociates from GnRH receptor
33
Q

What does GnRH analogue (agonist) do?

A
  1. bind to receptor
  2. signalling activated
  3. gonadotrophin synthesis and secretion
  4. few weeks - LH and FSH surge
  5. GnRH gets uncoupled (stays binding)
  6. GnRH receptor non-responsive to GnRH
  7. no LH/FSH released
34
Q

Where are GnRH analogues used (CLINICAL USES)?

A

prostate cancer, IVG, ovulation induction, breast cancer, ovarian cancer, endometrial cancer
Used controversially as gonadal protection prior to chemotherapy

  • > Uterine fibroids
  • > Endometriosis
  • > Polycystic ovary syndrome
35
Q

What are the gonadotrophins?

A

LH, FSH, hCG= heterodimeric peptides (alpha and beta subunits)

36
Q

What do all gonadotrophins have in common?

A

alpha subunit (glycosylated residues)

37
Q

Why are the beta subunits different in gonadotrophins?

A

different glycosylation and diff amino acid length

38
Q

Why is glycosylation important?

A

glycosylation needed to activate the receptor

carb side chains (glycosylation) change with pregnancy and menstrual cycle (hCG becomes hyperglycosylated)

39
Q

wHAT Is the function of LH in males?

A

testis= stimulate leydig cells= produce testosterone

40
Q

What is the function of LH in females?

A

theca cells= produce androgens
LH= ovulation
second half= coordinates progesterone production from corpus luteum

41
Q

What is the function of FSH in males?

A

sertolli cells= spermatogenesis

42
Q

What is the function of FSH in females?

A

follicle maturation
granulosa cell proliferation- produce oestrogen
androgen from theca cells transported to granulosa cells= aromatase- convert to oestrogen

43
Q

What kind of gland is the pituitary gland?

A

endocrine

44
Q

what artery delivers blood to the infundibulum?

A

The superior hypophyseal artery delivers blood to capillary network in upper infundibulum

45
Q

What is the blood supply to the posterior lobe of the pituitary gland?

A

Inferior hypophyseal artery

46
Q

What can you give a patient if they are anovulatory (dont ovulate)

A

Give timed pump giving GnRH every 90 minutes

47
Q

Which subunits are made in excess in gonadotrophins?

A

α-subunits are synthesized in excess with β-subunit limiting the hormone concentration.

48
Q

What is the difference between LH,FSH and hCG?

A

LH/FSH have N-linked carbohydrate side chains

hCG has N-linked and O-linked

Week 1 SEM 4 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions