Brainscape's Knowledge GenomeTM

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


See full index

Human Development > 1 - Reproductive Endocrinology and the Menstrual Cycle > Flashcards

1 - Reproductive Endocrinology and the Menstrual Cycle Flashcards

1
Q

What are the 2 main groups of molecules involved in human development?

A

Steroids and Glycoproteins

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

What are 5 features of steroids?

A
  • Lipids
  • 4 fused rings
  • 27C skeleton
  • Small
  • Central core molecule is cholesterol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are 3 types of steroids?

A
  • Oestrogen
  • Progestagens
  • Androgens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 3 types of Oestrogen?

A

E1 - Oestrone
E2 - Oestradiol (main oestrogen)
E3 - Oestriol (only in pregnancy)

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

Where is testosterone synthesised?

A

Leydig cells of testes in males

Ovary in females

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

Where is DHT synthesised?

A

Sertoli cells of testes in males

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

Where is Progesterone synthesised?

A

Adrenals in males

Ovary/Placenta in females

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

Where is oestradiol synthesised?

A

Ovary/placenta in females

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

Where is androstenedione synthesised?

A

Leydig cells

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

Where is DHEA synthesised?

A

Leydig cells

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

Where are oxidative enzymes located and what is the 1st step in steroid synthesis?

A
  • Mitochondria and endoplasmic reticulum

- Conversion of cholesterol to pregnenolone

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

What are the 6 steps of steroid synthesis in males?

A
  • GnRh in the hypothalamus stimulates FSH and LH from anterior pituitary
  • LH stimulates testosterone production from leydig cells
  • Target of testosterone and FSH is Sertoli cells
  • Sertoli cells have the enzyme 5a reductase which converts testosterone to DHT
  • Sertoli cells secrete ABP
  • ABP binds to testosterone and carries it to seminiferous tubule to stimulate spermatogenesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 6 steps of steroid synthesis in females?

A
  • GnRH stimulates FSH and LH from AP
  • LH stimulates testosterone by THECA cells in the ovarian follicle
  • Testosterone enters GRANULOSA cells surrounding oocyte
  • Converted into oestrogen by aromatase
  • Oestradiol stimulates formation of LH receptors on granulosa cells
  • Enables follicle to respond to LH and cause ovulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the potency of DHT, Testosterone, Androstenedione and DHEA?

A

DHT - 100%
Testosterone - 50%
Androstenedione - 8%
DHEA - 4%

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

What is the action of androgens?

A

Maintain male somatic tissue differentiation
Induce male secondary sexual characteristics
Support spermatogenesis
Influence sexual and aggressive behaviour (male & female)
Promote protein anabolism, somatic growth & ossification
Regulate gonadotrophin secretion (testosterone)
Induce body hair (in females – pubic & axillary)

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

What is the potency of 17b oestradiol, oestriol and oestrone?

A

Oestradiol - 100%
Oestriol - 10%
Oestroine - 1%

17
Q

What is the action of oestrogens?

A

Stimulate growth of mammary gland & endometrium
Induce female secondary sexual characteristics
Prepare uterus for spermatozoa transport
Increase vascular permeability
Mildly anabolic
Regulate gonadotrophin secretion

18
Q

What are the function of progestagens?

A

Luteal progesterone prepares the endometrium for implantation during the secretory phase of the menstrual cycle.

Effects cervix, vagina and breast

Placental progesterone maintains the endometrium (decidua) in pregnancy (after approximately 10-12 weeks)

19
Q

What is a glycoprotein?

A

Protein containing oligoscaccharide chains covalently attached to their polypeptide side chains

20
Q

What are the gonadotrophins produced by the anterior pituitary?

A
  • LH
  • FSH
  • TSH
21
Q

What is the name of the gonadotrophin produced by the placenta and the cell in placenta it is from?

A

Human chorionic gonadotropin (HCG)

Syncytiotrophoblast

22
Q

What is the funcitonal glycoprotein?

A

2 alpha and 2 beta subunits

23
Q

What is an alpha subunit?

A

Identical in FSH, LH, TSH and hCG - 92 Amino acids

24
Q

What is the beta subunit ?

A

Different in FSH, LH, hCG and gives them their specific biological action

25
Q

What is the function of FSH?

A

 Stimulates growth of immature Graafian follicles in the ovary to maturity
 Enhances production of androgen binding protein by the Sertoli cells of the testes amd is needed for spermatogenesis

26
Q

What is the function of LH?

A

 Surge triggers ovulation and converts the residual follicle into a corpus luteum
 Necessary to maintain luteal function
 Supports thecal cells in the ovary that provide androgens and hormonal precursors for oestradiol
 Acts upon the Leydig cells of the testes and is responsible for the production of testosterone

27
Q

What is the function of hCG?

A

 Maintains corpus luteum during pregnancy to ensure a constant release of progesterone to maintain the uterus lining during pregnancy

28
Q

What is the function of inhibin?

A

 Produced by males by Sertoli cells. Secreted when sperm count is high to inhibit pituitary release of FSH and hypothalamic secretion on GnRH
 In females it is produced by granulosa cells and helps to exert negative control on FSH production during the menstrual cycle

29
Q

What is the function of activin?

A

 Increases FSH activity and enhances the actions of LH in both males and females
 Belongs to the transforming growth factor beta family

30
Q

What is the funciton of Relaxin?

A

 Produced by females in the menstrual cycle (follicular development and oocyte maturation) and pregnancy (relaxation of ligaments and parturition)
 Produced in males in seminal fluid and enhances sperm mobility

31
Q

How many amino acids doe GnRh, GHRH, Oxytocin and Prolactin have?

A
  • Gonadotrophin releasing hormone (GnRH) – 10 amino acid peptide (hypothalamus)
  • Growth hormone releasing hormone (GHRH) – 44 amino acid peptide (hypothalamus)
  • Oxytocin – 9 amino acid peptide (hypothalamus/posterior pituitary)
  • Prolactin – 198 amino acid polypeptide (anterior pituitary)
32
Q

What are the 3 stages of the menstrual cycle?

A

o Menstrual phase: 1-5 days
o Proliferative phase: 6-14 days
o Secretory phase: 15-28 days

33
Q

How much blood is usually lost during menstruation?

A

50 - 150ml

34
Q

What happens during the menstrual phase?

A

Withdrawal of oestrogen and progesterone

endometrium collapses and is shed

35
Q

What happens during the proliferative phase?

A

o Oestrogen from the mature follicle stimulates thickening of endometrium
o Glands and spinal arteries form
o Oestrogen stimulates the synthesis of progesterone receptors on endometrial cells

36
Q

What happens during the secretory phase?

A

o Progesterone from corpus luteum acts on endometrium
o Progesterone stimulates enlargement of glands which begin secreting mucus and glycogen in preparation for implantation of oocyte
o If fertilization doesn’t occur, the corpus luteum degenerates
o Progesterone levels fall and the endometrium degenerates
o The cycle starts again with the first day of menstrual flow

37
Q

What happens if fertilisation doesnt occur?

A

o Corpus luteum degenerates and forms the corpus albicans
o Progesterone levels fall
o Endometrium breaks down
o Menstruation occurs

38
Q

What happens if fertilisation does occur?

A

o Blastocyst implants into maternal endometrium
o Developing placenta secretes human chorionic gonadotrophin (Hcg)
o Corpus luteum does not degenerate because of Hcg
o Progesterone levels do not fall because progesterone secretion is maintained by the corpus luteum
o Progesterone maintains the endometrium

Human Development (19 decks)

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