Module 3B Flashcards
1
Q
What letters denote male chromosomes?
A
- XY
2
Q
What letters denote female chromosomes?
A
- XX
3
Q
How is male genitalia differentiated?
A
- SRY antigen secreted by Y chromosome
- T stimulates Wolffian Duct to develop
- Sertoli cells of testes release MIH (Mullerian-inhibited factor)
- prostate converts T to DHT
4
Q
What do Wollfian Ducts develop into?
A
- epididymis
- vas deferens
- seminal vesicle
5
Q
What is the function of MIH?
A
- Mullerian-inhibited factor
- prevents Mullerian Duct from forming into genitalia
6
Q
What is the function of DHT?
A
- dihydrotestosterone
- stimulates development of scrotum, penis, & prostate
7
Q
How is female genitalia differentiated?
A
- No SRY antigen
- no male hormones present
- undifferentiated gonads naturally progress to ovaries
8
Q
What are the primary male sex organs?
A
- testes
9
Q
What is the function of the testes?
A
- production of spermatozoa
- production of T (testosterone)
10
Q
What two hormones are required for spermatogenesis?
A
- T
- FSH
11
Q
What is the male steroid hormone?
A
- testosterone (T)
12
Q
Where is T synthesized?
A
- Interstitial Cells of Leydig
13
Q
What are the general effects of T?
A
- anabolic
- androgenic
14
Q
What are the anabolic effects of T?
A
- stimulates GH secretion which leads to IGF-1 release
- end of puberty, promotes closure of growth plates
- stimulates protein synthesis in muscle
- summary - T has direct and synergistic effects on growth*
15
Q
What are the androgenic effects of T?
A
- development and maintenance of male accessory sex organs
- differentiation of male reproductive tract and brain
- development of secondary sex characteristics
- libido & potency
16
Q
What happens to T with age?
A
- decreases
17
Q
Where does spermatogenesis occur?
A
- seminiferous tubules
18
Q
What happens to the sperm after they are synthesized?
A
- stored in epididymis
19
Q
Describe the hormonal regulation of T
A
- GnRH stimulates FSH and LH from ant. pit.
20
Q
What does FSH do in the hormonal regulation of T?
A
- stimulates spermatogenesis in testes
- releases inhibin from testes
21
Q
What is the function of inhibin?
A
- inhibits FSH release from ant. pit.
22
Q
What does LH do in the hormonal regulation of T?
A
- stimulates synthesis & secretion of T from testes
23
Q
What inhibits LH?
A
- increased levels of T
24
Q
What is the primary female sex organ?
A
- ovaries
25
What is the function of the primary female sex organ?
- oogenesis
| - produces estrogens & progesterone
26
What is the function of estrogen?
- prepare for fertilization
- development & maintenance of female secondary sex characteristics
- protective effects on bone metabolism
- positive effect on CV
- CNS influences
27
What are the two cell types within a follicle?
- theca cells
| - granulosa
28
What hormones do the ovaries produce?
- estrogens
- progesterone
- inhibin
29
In summary, what is the function of progesterones?
- implantation
- maturation
- maintaining pregnancy
30
Describe LH's action during the menstrual cycle
- weeks 1 & 2, LH is required to stimulate ovarian follicle to produce estrogen
- surge at 14 d = LH stimulates ovulation
- weeks 3 & 4 = LH stimulates corpus luteum to release progesterone
31
Describe FSH's action during the menstrual cycle
- week 1 & 2 FSH stimulates growth of ovarian follicles and estrogen production
32
What are the phases of the menstrual cycle?
- follicular phase
- ovulation
- luteal phase
33
When is the follicular phase?
- days 1-14
34
When is ovulation?
- day 14
35
When is the luteal phase?
- days 14-28
36
What happens in follicular phase?
- endometrium thickens
| - ~20 ovarian follicles mature but 1 becomes dominant and other apoptose
37
What happens during ovulation?
- surge of LH leads to ovulation
| - uterus changes to allow sperm to enter
38
What happens in the luteal phase?
- follicle --> corups luteum
39
What happens in the luteal phase if fertilization occurs?
- corpus luteum produces hormones necessary for pregnancy
40
What happens in the luteal phase if fertilization does not occur?
- corpus luteum eventually degenerates
| - ischemia of endometrium (menses)
41
What are the stages of the follicular phase?
- early
- mid
- late
42
What happens during the early follicular phase?
- GnRH stimulates release of LH & FSH from ant. pit
- LH/FSH stimulate ovarian follicle growth & production of estrogens
- estrogens released into the bloodstream
43
What is the role of LH during the early follicular phase?
- stimulates the production of androgens in the theca cells
44
What is the role of FSH during the early follicular phase?
- stimulates the production of aromatase in the granulosa cells
45
What happens during the mid-follicular phase?
- dominant follicle emerges and continues to produce estrogen
- apoptosis of non-dominant follicles
46
What happens during the late follicular phase?
- estrogen levels increase dramatically & pos. feedback on release of LH
- peak levels of estrogen stimulates surge of LH
47
What stimulates ovum release from follicle aka ovulation?
- surge in LH
48
What happens during the luteal phase?
- empty dominant follicle become corups luteum which secretes progesterone and estrogen
- progesterone & estrogen now inhibit release of FSH/LH
49
What happens during the luteal phase if fertilization does not occur?
- corpus luteum secreteions progesterone/estrogen/inhibin which inhibit follicle development
- slowly decreases release of progesterone/estrogen/inhibin hormones
- decrease of progesterone/estrogen/inhibin levels constrict bloodflow & leads to menses
50
What happens during the luteal phase if fertilization does occur?
- corpus luteum will produce/maintain increased progesterone & estrogen levels
51
What do progesterone and estrogen levels do during pregnancy?
- stay elevated to support pregnancy and inhibit follicular development
52
What stimulates corpus lutem to produce estrogen/progesterone during pregnancy?
- hCG
53
What takes over production of estrogen and progesterone during pregnancy?
- placenta
54
Where is hCG produced and released?
- syncytiotrophoblast
55
What is the function of hCG?
- human chorionic gonadotropin
- maintains production of estrogens & progesterone in corpus luteum until placenta can take over
- suppresses follicle maturation in maternal ovaries
56
When is hCG measurable?
- 6-8d after conception
57
What does the placenta eventually produce?
- progesteron
- estrogen
- CRH
- hPL (human placental lactogens)
58
What is the function of CRH from the placenta?
- role in regulating birth
| - increase or decrease can result in premature or delayed birth
59
What is the function of hPL from the placenta?
- physical growth
| - lactation
60
When does menopause start?
- 45-55 y/o
61
What happens during menopause?
- ovarian tissue gradually ceases to respond to FSH & LH
| - decreased levels of estrogen and progesterone
