Brainscape's Knowledge GenomeTM

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


See full index

DEMS IV > reproductive axis > Flashcards

reproductive axis Flashcards

1
Q

Precursor of steroid hormones

A

choleserol- 27 carbon steroid molecule

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

Major classes of steroid hormones

A

glucocortocoids (ie. cortisol -C-21), mineralocorticoids (ie. aldosterone- C-21), and sex steroids

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

Major classes of sex steroids

A

progestins (C-21), androgens (C-19), and estrogens (C-18)

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

Principle sources of sex steroids

A

gonads, the adrenal cortex, and the placenta

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

List methods by which cholesterol is made

A

De novo from Co-enzyme A or from LDL in the circulation.

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

Where are sex steroids made

A

in the gonads, plus the adrenal cortex, skin and adipose tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. Describe key features in the biosynthesis of the sex steroids and describe the rate-limiting step.
A

Cholesterol is converted to steroid hormones by reduction of hydrocarbon side chains and hydroxylation of the 4 ring steroid nucleus. Rate limiting step is cleavage of the Cholesterol side chain to produce pregnenolone by 20,22 desmolase in the mitochondrial membrane. cholesterol > pregnenolone > progestins > androgens > estrogens

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

List the progestins

A

21-carbon sex steroids: pregnenolone, 17-alpha-hydroxy-pregnenolone, progesterone (major), and 17-alpha-hydroxy-progesterone (17-OH-P) (major).

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

Non-repro function of progestins

A

Progestins are also precursors for the production of aldosterone and cortisol by the adrenal gland.

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

Repro functions of progestins

A

Growth and development of the tissues and organs related to ovulation, menses, pregnancy, and lactation. Is a key feedback inhibitor at the hypothalamus and pituitary

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

List the androgens

A

19 carbon sex steroids: testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S), dihydrotestosterone (DHT), and androstenedione

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

Main sources of testosterone and DHEA

A

Test: 95% from testes, rest is from adrenal cortx. DHEA: mainly from adrenal cortex (marker of adrenal androgen activity)

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

Functions of androstenedione

A

In ovary: from the theca cells, precursor for ovarian estradiol by granulosa cells. Liver and adipose: precursor for extraglandualr estrogen formation

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

5-alpha reductase

A

converts testosterone to DHT in prostate and skin. DHT has much higher activity than testosterone and cannot be converted to estrogens

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

Testosterone functions

A

Androgenic: development of internal and external genitalia, devlopment/maintenance of secondary sex characteristics, spermatogenesis, libido, sebum production. Anabolic: growth of somatic tissues (bone,muscle, etc). Also feedback inhibitor at pituitary and hypothalamus

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

List the estrogens

A

18- carbon sex steroids: estrone (E1), estradiol (E2) and estriol (E3). They have one, two, and three hydroxyl groups, respectively

17
Q

How are estrogens made

A

androgens are converted into estrogens via aromatase in gonads, adipose tissue, liver, CNS

18
Q

Potency and location of estrone, estradiol and estriol

A

Estradiol is most potent (produced by granulosa cells of ovary, sertoli cells in testes). Estriol is least potent but serves as placental product. Estrone is derived from androstenedione in adipose tissue

19
Q

Functions of estradiol

A

Growth and development of the tissues and organs related to ovulation, menses, pregnancy, and lactation. Also feedback inhibitor of hypothalamus and pituitary

20
Q

How are sex steroids carried in bloodstream

A

bound to albumin, sex hormone binding globulin or corticosteroid binding globulin

21
Q

Where is GnRH produced

A

in neurons of the arcuate nucleus and preoptic area of the hypothalamus

22
Q

GnRH secretion

A

pulsatile- In adult males, approximately 8-14 pulses are released every 24 hours. In adult females, patterns of GnRH, FSH, and LH secretion vary throughout the menstrual cycle. Constant administration of GnRH actually suppresses the pituitary response

23
Q

Strcture of LH and FSH

A

The alpha subunits of LH, FSH, hCG and TSH are identical. The beta subunits are distinct and confer specific functional and immunologic characteristics to the intact molecule

24
Q

what is inhibin

A

Released by gonads. Exerts negative feedback on reproductive axis at the level of the pituitary.

25
Q

compare the gonadal cells in both sexes

A

Leydig (male) and theca (female) cells: interstitial cells, have LH receptors, make androgens and lack aromatase. Sertoli (male) and granulosa (female) cells: have FSH receptors, make inhibin, contain aromatase

26
Q

Function of Leydig cells

A

In response to LH, Leydig cells produce 95% of testosterone in males. It stimulates conversion of Cholesterol into pregnenolone by increasing amount of desmolase and enhancing its affinity for cholesterol.

27
Q

Function of Sertoli cells

A

In direct contact with spermatozoa - support cells. Organized into tubular epithelium called the seminiferous tubule with gap junctions btw cells. Maturing spermatogonia are located btw the sertoli cells and gap junctions btw sertoli cells and spermatozoa allow for maturation of gametes. Testosterone acts on the Sertoli cells

28
Q

FSH binding to Sertoli cells results in …

A

Increased production of androgen binding protein, enhanced conversion of testosterone from the Leydig cells into estradiol, and the production of inhibin. The Sertoli cells are the primary source of inhibin in males

29
Q

Function of Theca cells

A

In ovarian stroma surrounding follicles. In response to LH, they produce progesterone and androgens. Androstenedione diffuses to nearby granulosa cells

30
Q

Function of granulosa cells

A

In direct contact with oogonia, forming the primordial follicles. Androstenedione from theca cells is converted to estradiol by aromatase. Also produces progestins which are converted to androgens by the theca cells

31
Q
  1. Describe the 2-cell theory of sex steroid production and name the gonadal cell responsible for the production of sex steroids in men and women.
A

Sex steroid production requires 2 cells in both males and females

32
Q

Be able to label FSH, LH, estrogen, progestin, inhibin on a chart of the female menstrual cycle

A

ok see chart

33
Q

read the extra handouts if you have time

A

ya ok

DEMS IV (26 decks)

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