Sex Hormones Flashcards Preview

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Flashcards in Sex Hormones Deck (36):
1

Sex steroids are derivatives of?

Cholesterol (like all steroids)

2

What is the rate limiting step in steroid hormone synthesis?

side chain cleavage

3

What enzyme converts Pregnenolone to Progetsterone?

3B- Hydroxysterone beta dehydrogenase

4

Androstenedione gives rise to

Testosterone

5

Testosterone gives rise to

Estradiol

6

60% of seminal volume comes from where and consists of what?

Bulbourethral glands, seminal vesicles
-contains prostaglandins, fructose, citric acid

7

Semen =

sperm + secretions mainly from SV(60%) and Prostate (20%)

8

What pubertal changes are reversible?

spermatogenesis; size, secretion, content( fructose and citrate) of the sex accessory glands.

9

Non-reversible changes

voice, height, beard growth, libido, muscle mass

10

Two major functions of testis

gametogenesis and steroid production

11

sperm produced where?

seminiferous tubules

12

Testosterone produced where?

Leydig Cells

13

Spermatogenesis requires what hormones?

FSH, Testosterone (high conc)

14

Indirectly need:

LH for testosterone and GNRH for the production of FSH and lH

15

What are Sertoli cells?

The stimulate spermatogenesis and are the site of action of FSH and Testosterone.
- They provide nutrients to developing sperm and provide a blood brain barrier to many chemicals
- secrete inhibin
- phagocytose dead or developing

16

What is inhibin and where is it produced?

It is a hormone that is needed to decrease FSH

17

LH secretion occurs in what kind of pattern?

Pulsatile

18

LH secretion is required for what?

Testosterone production

19

Some tissues require testosterone to be metabolized to what?

Dihydrotestosterone (must become DHT) in order to reach the nucleus and produce androgenic actions

20

Examples of tissues that require transformation to DHT?

fetal formation of prostate and external genitalia
- pubertal enlargement of prostate, hair changes, acne

Processes that do not require change?
- pubertal growth of muscle, penis, scrotum

21

Testosterone is degraded by what organ?

Liver...excreted in the urine

22

Conversion to estradiol occurs where

adipose tissue, pituitary, hypothalamus

23

How is testosterone transported in teh blood?

Gonadal steroid binding globulin
- sex hormone binding globulin (70%)

24

How much T is free at any given time

3%

25

Actions of testosterone

- fetal differentiation of male sex organs
- induce changes in tissues at puberty
- Maintain size and function of most male ACCESORY organs ( seminal vesicles, prostate, increase fructose content, volume of secretions)
- Stimulate spermatogenesis
- Stimulate protein anabolism and long bone growth
- sex drive
- feedback to inhibit LH
- thick secretions (acne)
- pubic, axillary, facial hair growth

26

See slide on negative feedback.

ok. Important to note that testosterone feeds back to downregulate secretion of LH and FSH but it takes a ton of testosterone to downreulate FSH to bodybuilders know when they overdose because FSH decreases and size of testes decreases due to decrease in size of semeinferous tubules

27

Primary sex organs in the female?

Ovaries

28

Secondary Sex organs

oviducts, uterus, vagina
Glands: mucous and mammary

29

Estrogen

Stimulates growth and formation of ovaries and follicles

30

Low estrogen does what to LH and FSH?

inhibitory

31

Rising estrogen

stimulatory, leads to mid cycle LH burst that causes ovulation

32

very high E

inhibitory ...used to be used as BC

33

very low E + progesterone

birth control pills

34

What effect does E hav eon teh muscle and endothelial surfaces of the oviducts, uterus, vagina

Oviduct: growth of muscle and epithelium
- motility
- ciliary beating

Uterus: Myometrium growth, contractility

35

Cervical mucus

production of thin, watery, clear mucus

36

Vagina stimulates growth of mammary glands, branching of ducts, fat deposition, nipples and areolae growth and darkening

ok