Endocrinology - Lecture 5 Flashcards
(103 cards)
1
Q
What are the primary reproductive organs?
A
testes in the male and ovaries in the female
2
Q
What are the 2 functions of gonads?
A
- gametogenesis
- secretion of sex hormones
3
Q
What are the 3 kinds of sex hormones?
A
- testosterone (men)
- estrogen and progesterone (fem)
4
Q
Are the differences in reproductive endocrinology in males and female quantitative or qualitative?
A
quantitative
5
Q
What does estrogen maintain in males?
A
bone density
6
Q
Where is estrogen produced in males?
A
in tissues
7
Q
What does aromatase convert testosterone to?
A
estrogen
8
Q
What does estrogen deficiency in males lead to?
A
- increased to body fat
- contributes to sexual desire and erectile function
9
Q
What secretes GnRH?
A
hypothalamus
10
Q
Where does GnHR travel to?
A
anterior pituitary
11
Q
What 2 pituitary gonadotropins does the GnRH stimulate the release of?
A
FSH and LH
12
Q
What do FSH and LH stimulate the development of?
A
spermatozoa/ova and sex steroids
13
Q
What do sex steroids exert effects in?
A
gonads
14
Q
What is the principal function of the testes? (2)
A
spermatogenesis and steroidogenesis
15
Q
What are precursor germ cells called?
A
spermatogonia
16
Q
Where does the process of spermatogenesis take place?
A
in the coiled seminiferous tubules
17
Q
How long does the process of maturation from immature spermatozoon take?
A
60 days
18
Q
What are the 2 cell types critical for maturation of spermatozoa?
A
Leydig cells and Sertoli cells
19
Q
Where are Leydig cells located?
A
outside seminiferous tubules
20
Q
Where are Sertoli cells located?
A
within the seminiferous tubules
21
Q
In response to LH, what do Leydig cells synthesize?
A
androgens
22
Q
What do Sertoli cells envelop during their development?
A
germ cells
23
Q
What do Sertoli cells synthesize in response to FSH? (2)
A
ABP and inhibin
24
Q
What kind of concentrations does spermatogenesis depend on?
A
androgen
25
How much higher do androgen concentration in seminiferous tubules need to be compared to androgen concentration in circulation otherwise spermatogenesis ceases?
10x higher
26
Sertoli cells ensure high ___ concentration within seminiferous tubules.
androgen
27
What 2 feedback loops regulate testicular androgen?
1. hypothlamic-pituitary-Leydig cell axis
2. hypothalamic-pituitary-seminiferous-tubules axis
28
29
What do Leydig cells produce?
androgen
30
What does androgen inhibit the release of (3)?
GnRH, LH and RSH
31
What does non steroidal inhibin secreted by sertoli cells inhibit?
FSH
32
What 2 things do ovaries produce?
mature eggs and steroid hormones
33
What does ovary contain at birth?
oocytes
34
How many oocytes are there at birth?
2 millions
35
How many ova are left after puberty?
400,000
36
What are oocytes surrounded by?
granulosa cells
37
What is the basement membrane of the oocytes made up of?
primordial follicles
38
What is the fundamental reproductive units of the ovary?
primordial follicles
39
When does the growth of primordial follicles into primary follicles begin by?
an unknown initiating events
40
What is growth of primary follicles controlled by? (2)
gonadotropins and steroid hormones
41
What is degeneration of follicles called?
atresia
42
What occurs during the initial stages of oocyte development in follicular growth?
initially, enlargement and differentiation of the oocyte take place, leading to the elaboration of the zona pellucida, an acellular layer rich in glycoproteins surrounding the oocyte.
43
What happens to granulosa cells during the formation of primary follicles, and what influences this process?
granulosa cells divide and increase to 2 or more layers, forming primary follicles. This process is influenced by FSH and estrogens, with estrogens being important for the expression of LH receptors on granulosa cells.
44
Describe the development of a secondary follicle.
under the influence of FSH and LH, the primary follicle develops into a secondary follicle. The secondary follicle expresses receptors for FSH, estrogens, and LH. Additionally, the follicular antrum appears, containing secretions from granulosa cells.
45
What happens to granulosa cells under the combined influence of FSH and LH in the formation of the preovulatory follicle?
under the combined influence of FSH and LH, granulosa cells elaborate follicular fluid. This fluid takes up the larger portion of the preovulatory follicle, also known as the late secondary follicle, Graafian follicle, or mature follicle.
46
What does follicular development lead to? (2)
1. follicular atresia
2. ovulation
47
What does a ruptured follicle transform into?
corpus luteum
48
What does the corpus luteum secrete?
progesterone and estrogens
49
What 2 cells contribute to the formation of the corpus luteum?
theca and granulosa cells
50
When does the corpus luteum produce large amounts of progesterone and estrogens? When does it stop?
a few days following ovulation and stops unless implanation of fertilized ovum happens
51
What does the corpus luteum transform into upon implantation?
corpus luteum of pregnancy
52
What limits the lifespan of corpus luteum?
absence of implantation
53
What induces luteal regression?
prostaglandins
54
What does luteal regression decrease?
steroidogenesis
55
What can trigger the initiation of the next reproductive cycle?
decrease of plasma progesterone and estrogen
56
Why does the endometrium thicken prior to day one of the menstrual cycle?
due to estradiol
57
What induces the appearance of specialized glycogen-secreting glands?
progesterone
58
What are the levels of estradiol and progesterone when bleeding begins?
very low
59
What reduces the blood supply in the endometrium?
the blood vessels constricting
60
What do low estradiol and progesterone increase?
FSH secretion
61
What do low estradiol and progesterone decrease?
non-steroidal ovarian inhibin
62
Under the influence of what hormones do cohots of ovarian follicles develop?
FSH
63
What does FSH stimulate to proliferate?
granulosa cells
64
What does FSH do to the production of estrogen and granulosa cell proliferation?
increase
65
What happens during day 8 of the menstrual cycle?
one follicle becomes dominant and committed to further development
66
What does the dominant follicle produce increasingly more of?
estradiol
67
What does increasing estradiol do to uterine endometrium proliferation?
stimulate it
68
What is the endometrium by day 13?
very thick
69
What does estradiol produce during day 13?
endometrial progesterone receptors
70
Although moderate estradiol concentrations stimulate ___ synthesis, they inhibit ___ release.
LH
71
Under the influence of developing follicle, ___ concentrations continue to build.
estrogen
72
What happens during day 14 of the mestrual cycle?
elevated estrogen concentrations stimulate LH release
73
What kind of feedback does estrogen exert?
negative feedback
74
What does estrogen do to GnRH and LH release?
decrease it
75
What happens to the ovary follicle at day 14?
it's huge and ovum is ejected
76
What do pills contain?
estrogen and progesterone
77
What does the pill suppress the release of?
LH and FSH
78
What happens during the luteal phase?
egg and corpus luteum degenerates
79
How long does the luteal phase last for?
14 days
80
What is unfertilized egg taken by at ovulation?
fimbria
81
What stage does the egg start dividing?
blastocyst
82
What does the blastocyst differentiate into?
trophoblast and inner cell mass
83
What does the trophoblast become?
placenta
84
What will form the embryo?
inner cell mass
85
What does trophoblast start to synthesize around the time or implantation?
HCG
86
What is the function of HCG?
stimulates the corpus luteum to contrinue secreting gonadal steroids
87
When is the fetoplacental unit formed?
about 12th week of pregnancy
88
What forms the biological pregnancy test?
HCG
89
What hormone stimulates the growth of alveoli?
progesterone
90
Why does most breast enlargement happen?
due to deposition under the glandular tissue
91
Under which hormones does ductal and alveolar structures develop?
estrogen, progesterone, prolactin, human placental lactogen
92
What is milk production during pregnancy controlled by?
prolactin
93
What inhibits the secretion of milk production?
high estrogen levels
94
After parturition, levels of estrogen ___, while levels of prolactin remain ___.
decrease, high
95
What causes ducts to contract and cause milk ejection?
oxytocin
96
What can be transmitted from the mother to infant through breastmilk?
infectious agents
97
What does maintained nursing stimulate?
prolactin production
98
What does prolactin production inhibit the secretion of?
FSH and LH
99
If suckling is not frequent enough then ovulation and pregnancy may ___.
occur
100
What is menopause?
loss of ovarian steroid production
101
What does the lack of estrogen during menopause induce?
hot flases, dry vagina, restlessness, bone loss
102
What is the most reliable indicator for onset of menopause?
constantly high levels of plasma FSH
103
What does menopause cause cessation of?
ovarian steroid hormone production - eleminated - feedback loop and rise in FSH and LH
