Sex hormones

Question 1

Testosterone actions

Answer 1

Stimulates enlargement of testes and male accessory organs

Stimulates development of male secondary sex characteristics

Suppresses FSH and LH secretion and GnRH production

Question 2

Metabolism of testosterone

Answer 2

by 5-alpha reductase to active metabolite dihydrotestosterone (DHT)

Question 3

Dihydrotestosterone (DHT)

Answer 3

causes development of male external genitalia

by binding to cytoplasmic androgen receptors

Question 4

Leydig cells of testes

Answer 4

activated by LH and secrete testosterone

Question 5

Sertoli cells

Answer 5

activated by FSH

secrete anti-mullerian hormone and androgen binding protein (ABP)

Question 6

Anti-mullerian hormone (AMH) function

Answer 6

causes regression of mullerian duct

Question 7

Androgens made within adrenal cortex

Answer 7

testosterone, androstenedione and dehydroepiandrosterone (DHEA)

Question 8

Dehydroepiandrosterone (DHEA) function

Answer 8

causes early development of pubic/body hair in boys and girls

Question 9

testosterone release process

Answer 9

1. testes release testosterone
2. 5-alpha reductase convert testosterone to DHT
3. DHT binds to androgen receptor which releases heat shock proteins (hsp)
4. hsp migrate to nucleus and bind to specific regions of DNA that contain Androgen Response Elements (ARE)
5. ARE drive expression of genes that increase: growth, survival and PSA production

Question 10

sex hormones secreted by pituitary gland

Answer 10

LH and FSH

Question 11

hormone released by hypothalamus

Answer 11

GnRH (gonadotropin releasing hormone)

Question 12

role of GnRH

Answer 12

stimulation of LH and FSH secretion

Question 13

role of FSH and LH

Answer 13

stimulate gamete production in the gonads

Question 14

how many sperm cells does 1 germ cell (spermatogonium) produce

Answer 14

1 germ cell = 1 primary spermatocyte = 2 secondary spermatocytes = 4 sperm cells

Question 15

what is the product of Sex-determining region of Y chromosome (SRY gene)

Answer 15

testis-determining factor

Question 16

male development at 10-week old foetus

Answer 16

1. SRY protein in male embryo detects medulla of biopotential gonad to develop into testes
2. Anti-Mullerian hormone from testis causes the mullerian ducts to diappear

Question 17

male development at birth

Answer 17

1. testosterone from testis converts Wolffian duct into seminal vesicle, vas deferens and epididymis
   (DHT control prostate development)

Question 18

what happens to gonad (cortex) in male and female development

Answer 18

M - regresses

F - forms ovary

Question 19

what happens to Gonad (medulla) in male and female development

Answer 19

M - forms testis

F - regresses

Question 20

what happens to Gonad (medulla) in male and female development

Answer 20

M - forms testis

F - regresses

Question 20

what happens to Gonad (medulla) in male and female development

Answer 20

M - forms testis

F - regresses

Question 20

what happens to Gonad (medulla) in male and female development

Answer 20

M - forms testis

F - regresses

Question 21

what happens to Wolffian duct in male and female development

Answer 21

M - forms epididymis, vas deferens and seminal vesicle (testosterone present)
F - regresses (testosterone absent)

Question 22

what happens to Mullerian duct in male and female development

Answer 22

M - regresses (AMH present)

F - forms fallopian tubes, uterus, cervix and upper half of vagina (AMH absent)

Question 23

What do primary testicular failure (M) and hypogonadotropic hypogonadism (M+F)

Answer 23

infertility and associated hypogonadism and lack of 2nd sexual characteristics

Question 24

Ovarian steroid hormones

Answer 24

1. estrogens C18 2. progestagens C21 3. Androgens C19

Question 25

how many egg cells does 1 germ cell (oogonium) produce

Answer 25

1 germ cell = 1 primary oocyte = 1 secondary oocyte (egg cell) = 1 egg cell released from ovary at ovulation

Question 26

female development at 10 weeks (foetus)

Answer 26

1. Gonadal cortex becomes ovary in absence of SRY protein and under influence of female-specific gene 2. absence of testosterone causes Wolffian duct to degenerate

Question 27

Female development at birth

Answer 27

3. absence of anti-mullerian hormone allows Mullerian duct to become fallopian tubes, upper half of vagina, uterus

Question 28

Role of estrogen

Answer 28

- maturation of germ cells - anabolic effects on bone and cartilage (osteoporosis) - maintenance of pregnancy - growth development metabolism and reproduction - labour and lactation - development of tissue that will allow for implantation of blastocysts - development and regulation of female reproductive system and secondary sex characteristics

Question 29

increased progesterone effect in women

Answer 29

thickening of uterine wall

Question 30

increased inhibin effect in women

Answer 30

LH and FSH inhibition

Question 31

increased estrogen effect in women

Answer 31

release of inhibin | inhibition of FSH

Question 32

physiological stages of fertilisation

Answer 32

1. sperm cell fertilises ovum 2. divides into 2 then 4 cells (blastocysts) 3. blastocyst attaches itself to uterine wall (6-7 days) 4. implantation of blastocyst in endometrium (11/12 days) = embryo at 4 weeks

Question 33

role of Human Chorionic Gonadotropin (hCG)

Answer 33

hormone detected in pregnancy tests | prevents degeneration of corpus luteum = continued secretion of estrogen and progesterone

Question 34

role of estrogen in pregnancy

Answer 34

inhibits FSH and LH = no subsequent ovulation

Question 35

role of progesterone in pregnancy

Answer 35

maintains integrity of uterine wall

Question 36

placental hormones

Answer 36

``` Placental lactogen (hPL) hCG progestins lutenising hormone (LH) estrogens ```

Question 37

labour related drugs

Answer 37

oxytocin | selective beta2 adrenergic receptor antagonist = prevents smooth muscle contraction

Question 38

hormones involved with lactation

Answer 38

E2 - ductal growth progesterone - inhibits milk production and secretion in late pregnancy prolactin oxytocin - stimulated by estrogens and inhibited by progesterone

Question 39

physiology of menopause

Answer 39

increased LH and FSH - compensates decreased estrogen | ovaries fail to respond to FSH - number of remaining follicles decreases

Question 40

physiological signs of menopause

Answer 40

decreased estrogen production decreased testosterone thinner vaginal walls

Question 41

hormonal control of early to mid-follicular phase of menstrual cycle

Answer 41

1. low level estrogen = -ve feedback to GnRH, FSH and LH 2. increased estrogen secretion by follicle 3. granulosa cells secrete AMH = prevents more follicles developing

Question 42

hormonal control of late follicular phase and ovulation of menstrual cycle

Answer 42

1. increased estrogen and progesterone = LH surge (important for ovulation) 2. FSH suppressed by inhibin

Question 43

hormonal control of early to mid-luteal phase of menstrual cycle

Answer 43

1. increased inhibin, estrogen and progesterone = FSH and LH inhibition

Question 44

hormonal control of late luteal phase of menstrual cycle

Answer 44

1. decreased estrogen and progesterone when corpus luteum dies 2. gonadotropins start follicular development for a new cycle

Question 45

4 stages of menstrual cycle

Answer 45

1. early to mid-follicular phase 2. late follicular phase and ovulation 3. early to mid-luteal phase 4.