M6-GONADAL FUNCTION Flashcards
1
Q
What are the dual functions of the testes
A
Spermatogenesis and hormonogenesis
2
Q
What cells form sperm cells
A
Spermatogonia
3
Q
What processes do spermatogonia undergo
A
Mitosis and meiosis
4
Q
What is the result of spermatogonia undergoing mitosis and meiosis
A
Haploid cells that form mature sperm
5
Q
What are the parts of a mature sperm
A
Head
6
Q
What is the predominant hormone secreted by the testes
A
Testosterone
7
Q
What hormones control testosterone production
A
FSH and LH
8
Q
What cells does FSH act on in the testes
A
Germinal stem cells
9
Q
What cells does LH act on in the testes
A
Leydig cells
10
Q
What is the recommended time of sampling for testosterone
A
8-10 AM
11
Q
At what time of day is testosterone level highest
A
0.25
12
Q
At what time of day is testosterone level lowest
A
0
13
Q
To what protein is about 50% of testosterone bound
A
Albumin
14
Q
To what protein is about 45% of testosterone bound
A
Sex-hormone binding globulin (SHBG)
15
Q
What percentage of testosterone is free
A
2-3%
16
Q
What provides feedback control to the hypothalamus and pituitary
A
Testosterone and inhibin
17
Q
Where are neuroendocrine cells located
A
Hypothalamus
18
Q
What do neuroendocrine cells synthesize and secrete
A
Gonadotrophin releasing hormone
19
Q
Where does gonadotrophin releasing hormone bind
A
Specific cell membrane receptors on the gonadotrophs
20
Q
Where are gonadotrophs located
A
Anterior pituitary
21
Q
What is the result of gonadotrophin releasing hormone binding to gonadotrophs
A
Synthesis of FSH and LH
22
Q
What cells does FSH induce
A
Sertoli cells
23
Q
What does FSH induce Sertoli cells to synthesize and secrete
A
Androgen binding protein
24
Q
Where is androgen binding protein secreted
A
Into the lumen of seminiferous tubules
25
What is the role of androgen binding protein
Maintain high testosterone concentration required for spermatogenesis
26
What cells does LH induce
Leydig cells
27
What does LH induce Leydig cells to synthesize
Testosterone
28
What are the target tissues of testosterone
Skeletal muscles
29
What effect does testosterone have on the hypothalamus and anterior pituitary
Negative feedback effect
30
What does a negative feedback effect of testosterone cause
Decreases the production of gonadotrophin releasing hormone by the hypothalamus and FSH and LH by the anterior pituitary
31
What cells synthesize and secrete inhibin
Sertoli cells
32
With what cells does inhibin interact
Gonadotrophs in the anterior pituitary
33
What effect does inhibin have on gonadotrophs
Negative feedback effect
34
What hormone does inhibin decrease the synthesis of
FSH
35
What is the effect of inhibin on LH
No effect
36
What characterizes hypergonadotrophic hypogonadism
Low testosterone
37
What is the genetic cause of Klinefelter's syndrome
Presence of an extra X chromosome (XXY syndrome)
38
How common is Klinefelter’s Syndrome
Occurs in about 1 out of 400 men
39
What are the physical characteristics of Klinefelter's syndrome
Small
40
What semen abnormality is seen in Klinefelter's syndrome
Azoospermia (absence of sperm in male’s semen) and sterility (infertility)
41
What are the lab results in Klinefelter's syndrome
Elevated FSH and LH and reduced testosterone
42
What causes elevated FSH and LH in Klinefelter's syndrome
Increased aromatase activity (elevated estrogen levels)
43
What is the function of aromatase
Enzymes needed in synthesize of estrogen
44
What is Testicular Feminization Syndrome
Most severe form of androgen resistance syndrome
45
What does Androgen resistance syndrome result in
Lack of testosterone action in the tissue
46
What physical development results from Testicular Feminization Syndrome
Female phenotype
47
What are the lab results in Testicular Feminization Syndrome
Normal or elevated serum testosterone and elevated FSH and LH
48
What does 5a – Reductase Deficiency result in
Decreased testosterone levels
49
What physical development is seen in 5a – Reductase Deficiency
Similar to the female phenotype
50
What does Myotonic Dystrophy present with
Primary hypogonadism
51
When does testicular failure typically present in Myotonic Dystrophy
Fourth decade of life
52
What can result from postpubertal mumps infection
Orchitis and permanent testicular injury
53
What are the causes of Testicular Injury and Infection
Viral orchitis (due to mumps) and HIV infection and Radiation and chemotherapy
54
What is the long term result of radiation and chemotherapy to cancer
Long term testicular damage
55
What characterizes Sertoli Cell – Only Syndrome
Lack of germ cells
56
What are the lab results in Sertoli Cell – Only Syndrome
Small testes
57
What is the only procedure to confirm Sertoli Cell – Only Syndrome
Testicular biopsy
58
What characterizes hypogonadotrophic hypogonadism
Low testosterone levels
59
What is Kallmann’s Syndrome
An inherited
60
How common is Kallmann’s Syndrome
Occurs in about 1 out of 10
61
What other symptoms are present in Kallmann’s Syndrome
Anosmia (inability to smell) and midline defects
62
What do midline defects alert clinicians to suspect
Kallmann’s Syndrome
63
What are other possible symptoms in Kallmann’s Syndrome
Red-green color blindness
64
What causes hyperprolactinemia
Drug-induced or prolactin-producing tumors
65
What does hyperprolactinemia impair
Secretion of FSH and LH
66
What percentage of men with diabetes have low testosterone
At least 25%
67
In diabetic men with low testosterone
what other hormone level is inappropriately low
68
What mechanisms cause hypogonadism in diabetes
Insulin resistance and inflammation
69
What occurs gradually after age 30
Reduction in testosterone
70
What is the average decline in testosterone per decade after age 30
About 110 ng/dL every decade
71
What were the results of the Baltimore Longitudinal Study of Aging
19% at age 60
72
What happens to SHBG with age
Elevation of SHBG by about 1% per year
73
What can cause pituitary disease
Tumors
74
In male hypogonadism
what are the lab results for primary deficiency
75
What is the underlying issue in primary hypogonadism
Destruction of male gonads (testes)
76
In male hypogonadism
what are the lab results for secondary deficiency
77
What is the underlying issue in secondary hypogonadism
Destruction of anterior pituitary
78
What lab results are expected in primary excess hypogonadism
low FSH and LH; high testosterone
79
What lab results are expected in secondary excess hypogonadism
high FSH and LH; high testosterone
80
What symptoms of hypogonadism should be corroborated with low testosterone levels
Loss of secondary sexual characteristics and osteoporosis
81
What is the treatment for hypogonadism
Testosterone Replacement Therapy
82
How may Testosterone Replacement Therapy be administered
transdermal
83
What are the dual functions of the ovaries
Gamete (ovum) and steroid hormone production
84
What synchronizes ovarian and menstrual events
Hormones secreted by the hypothalamus
85
What prepares the uterus for implantation
Hormones secreted by the hypothalamus
86
What happens without implantation
Uterine lining is shed
87
What is the typical duration of the menstrual cycle
28 ± 3 days
88
What is the average menstrual flow duration
2-4 days
89
What class of hormone is estrogen
Carbon-18 steroid hormone
90
What does estrogen promote
Breast
91
What else does estrogen affect
the skin
92
What uterine changes are estrogens responsible for
Follicular phase changes
93
What happens in estrogen deficiency
Irregular and incomplete development of the endometrium
94
What is the principal estrogen produced in the ovary
Estradiol
95
What is the most abundant estrogen in post menopausal women
Estrone
96
What is the major estrogen secreted by the placenta during pregnancy
Estriol
97
What class of hormone is progesterone
Carbon-21compound within the steroid family
98
What produces progesterone
Corpus luteum
99
What is the prime secretory product of the ovary
Progesterone
100
What is the function of progesterone
Prepares the endometrium for embryo implantation
101
What is the dominant hormone responsible for the luteal phase
Progesterone
102
After menopause
what produces progesterone
103
What is the result of progesterone deficiency
Failure of implantation of the embryo
104
What androgens are produced by the ovaries
androstenedione
105
What class of hormone are androgens
carbon-19 compounds
106
What results from excess androgen production in women
Hirsutism (excessive hair growth)
107
How long does androgen synthesis continue
Well into advanced age
108
How does androgen synthesis compare after menopause
Unlike estrogen and progesterone which are not produced by the ovaries after menopause
109
What is the function of inhibins A and B
inhibit FSH production
110
What is the function of activin
enhances FSH secretion and induces sterioidogenesis
111
What does sterioidogenesis refer to
Steroid hormone synthesis
112
What is the normal menstrual cycle length
25-35 days
113
What is primary amenorrhea
never menstruated by age 16 years
114
What is secondary amenorrhea
has at least one menstrual cycle followed by absence of menses for a minimum of 3-6 months
115
What is oligomenorrhea
Infrequent irregular menstrual bleeding
116
What is menorrhagia
Uterine bleeding in excess of 7 days
117
What are the causes of hypogonadotrophic hypogonadism
Weight loss associated with anorexia nervosa or various disease processes
118
What characterizes hypergonadotrophic hypogonadism
ovarian failure resulting in elevation of FSH concentrations
119
What is premature ovarian failure
primary hypogonadism in a woman before the age of 40
120
What can cause premature ovarian failure
Congenital chromosomal abnormality (Turner’s syndrome) or premature menopause
121
What is Turner's syndrome
Condition affecting only females; results when one of the X chromosomes is missing or partially missing
122
What does PCOS cause
Infertility
123
What symptoms and lab abnormalities are reversed with weight loss and increased physical activity
Those symptoms of PCOS
124
What does ovarian ultrasound reveal in PCOS
Multiple cysts
125
What drug normalizes menstrual cycle and improves conception rates
Metformin
126
What is hirsutism
Abnormal
127
What are the causes of hirsutism
Idiopathic (60% of cases) and PCOS (35%)
128
What were some negative side effects seen in women on conventional hormone replacement combinations
Increased incidence of invasive breast cancer and venous clot formation
129
What positive effects were seen in women on conventional hormone replacement combinations
Reductions in bone loss
130
What is the function of FSH in hormonal control of testicular function
induces sertoli cells to synthesize and secrete androgen binding protein in to the lumen of seminiferous tubules
131
What is the function of LH in hormonal control of testicular function
induces leydig cells to synthesize testosterone
132
What is the effect of estradiol on the hypothalamus and anterior pituitary near the end of the follicular phase
it stimulates a positive feedback effect on hypothalamus and anterior pituitary causing increase in the production of gonadotrophin releasing hormone
133
What hormones act on uterine endometrium to cause development of exocrine gland producing the secretory phase of the uterine endometrial cycle
Estradiol and Progesterone
134
What is synthesized and secreted by corpus luteum
Inhibin A
135
What is synthesized and secreted by developing follicle
Inhibin B
136
What is the action of Inhibin A and Inhibin B
Both suppresses FSH and LH
