Sex Hormones Flashcards

1
Q

Sex steroids are derivatives of?

A

Cholesterol (like all steroids)

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2
Q

What is the rate limiting step in steroid hormone synthesis?

A

side chain cleavage

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3
Q

What enzyme converts Pregnenolone to Progetsterone?

A

3B- Hydroxysterone beta dehydrogenase

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4
Q

Androstenedione gives rise to

A

Testosterone

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5
Q

Testosterone gives rise to

A

Estradiol

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6
Q

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

A

Bulbourethral glands, seminal vesicles

-contains prostaglandins, fructose, citric acid

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7
Q

Semen =

A

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

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8
Q

What pubertal changes are reversible?

A

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

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9
Q

Non-reversible changes

A

voice, height, beard growth, libido, muscle mass

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10
Q

Two major functions of testis

A

gametogenesis and steroid production

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11
Q

sperm produced where?

A

seminiferous tubules

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12
Q

Testosterone produced where?

A

Leydig Cells

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13
Q

Spermatogenesis requires what hormones?

A

FSH, Testosterone (high conc)

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14
Q

Indirectly need:

A

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

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15
Q

What are Sertoli cells?

A

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
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16
Q

What is inhibin and where is it produced?

A

It is a hormone that is needed to decrease FSH

17
Q

LH secretion occurs in what kind of pattern?

A

Pulsatile

18
Q

LH secretion is required for what?

A

Testosterone production

19
Q

Some tissues require testosterone to be metabolized to what?

A

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

20
Q

Examples of tissues that require transformation to DHT?

A

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
Q

Testosterone is degraded by what organ?

A

Liver…excreted in the urine

22
Q

Conversion to estradiol occurs where

A

adipose tissue, pituitary, hypothalamus

23
Q

How is testosterone transported in teh blood?

A

Gonadal steroid binding globulin

- sex hormone binding globulin (70%)

24
Q

How much T is free at any given time

A

3%

25
Q

Actions of testosterone

A
  • 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
Q

See slide on negative feedback.

A

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
Q

Primary sex organs in the female?

A

Ovaries

28
Q

Secondary Sex organs

A

oviducts, uterus, vagina

Glands: mucous and mammary

29
Q

Estrogen

A

Stimulates growth and formation of ovaries and follicles

30
Q

Low estrogen does what to LH and FSH?

A

inhibitory

31
Q

Rising estrogen

A

stimulatory, leads to mid cycle LH burst that causes ovulation

32
Q

very high E

A

inhibitory …used to be used as BC

33
Q

very low E + progesterone

A

birth control pills

34
Q

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

A

Oviduct: growth of muscle and epithelium

  • motility
  • ciliary beating

Uterus: Myometrium growth, contractility

35
Q

Cervical mucus

A

production of thin, watery, clear mucus

36
Q

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

A

ok