Reproductive 2

Question 1

what is the starting molecule for sex hormones

Answer 1

cholesterol

Question 2

dietery cholesterol vs blood cholesterol

Answer 2

• dietery in food, goes through GI tract
• blood cholesterol : synthesized by the liver, GI tract and other cells

Question 3

how is cholesterol transported

Answer 3

via lipoproteins

Question 4

HDL

Answer 4

• high density lipoprotein
• peripheral cells to liver

Question 5

LDL

Answer 5

• low density lipoprotein
• liver to peripheral cells

Question 6

VLDL

Answer 6

• very low density lipoprotein
• liver to peripheral cells

Question 7

chylomicron

Answer 7

small intestine to liver

Question 8

sex hormones - pathways

Answer 8

cholesterol
|
pregnenolone -> dehydroepiandrosterone ; DHEA
|
progesterone -> androstenedione -> estrone
|. ||
testosterone -> estradiol

|

Dihydrotestosterone; DHT

Question 9

sex hormones - pathways

Answer 9

• have wide-ranging effects in the body, not just sexual function but also effects on bones, brain, blood vessels, etc.
• different amounts produced in males and females
• produced primarily by the gonads - ovaries and testies - but also other sites like adrenal cortex, skin, adipose, etc.

Question 10

sex hormones - females

Answer 10

• dominance : progesterone/ estrogens (mainly estradiol; small amounts estrone, estriol)
• androgens - mainly DHEA from adrenal cortex (especially post menopause) / testosterone from ovaries

Question 11

sex hormones - males

Answer 11

• dominance : androgens (testosterone, DHEA, androstenedione, DHT)
• Estrogens : mainly conversion of androstenedione and testosterone by testes and other tissues like adipose

Question 12

gonadotropins

Answer 12

GnRH gonadotropin releasing hormone is secreted in hypothalamus and direct blood vessels to pituitary gland

-triggers secretion and release of gonadotropins from anterior pituitary gland

→ FSH (follicle stimulating hormone)

→ LH (luteinizing hormone)

• gonadotropins have effects on gonads (gametogenesis)
• release and response to sex hormones

Question 13

gonadotropins in fetal life to infancy

Answer 13

-GnRH/ gonadotropins (in males, females) and gonadal sex hormones (especially testosterone in males) secreted at relatively high levels

Question 14

Gonadotropins in childhood to the onset of puberty

Answer 14

-GnRH/gonadotropins and gonadal sex hormones (in males and females) are low

Question 15

gonadotropins in puberty to adulthood

Answer 15

• GnRH/ gonadotropins and gonadal sex hormones increase markedly (significantly) (in both males and females)
• males : testosterone driven development of secondary sex characteristics; spermatogenesis
• females : estrogen and progesterone driven development of secondary sex characteristics; cyclical variations (menstrual cycle) affecting oogenesis and follicle maturation

Question 16

male hormonal control

sertoli cells

Answer 16

→ stimulate spermatogenesis

→release hormone inhibin to bloodstream effecting feedback (negative feedback to FSH and LH)

Question 17

leydig cells

Answer 17

• produce testosterone
• in testes

→locally, stimulates sertoli cells

-in bloodstream

→effecting GnRH and gonadotropins via negative feedback

→reproductive tract, other organ effects

see graph

Question 18

male reproductive function - andropause

Answer 18

with aging ; testes ultimately become less responsive to gonadotropins

andropause : decrease in sexual hormones (testosterone)

→diminished capacity not cessation (may have reproductive capacity into nineties)

→ decline more subtle than females

→steady decrease in testosterone secretion, testicular function beginning ~ 40 years

• onset variable - typically 55 to 65 years
• decrease secondary sex characteristics (like muscle strength), spermatogenesis (fewer viable sperm)
• some manifest increased emotional problems such as depression
• increased aging-associated diseases

Question 19

604-306-2220

Question 20

androgens

Answer 20

hormones that contribute to growth and reproduction in both men and women