Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Phys II Unit III > 3 Puberty > Flashcards

3 Puberty Flashcards

1
Q

What are the three levels of sexual differentiation?

A

Genetic sex (depends on the combo of sex chromosomes at the time of conception)

Gonadal sex (whether testes or ovaries develop - determined by presence or absence of Y chromosome)

Phenotypic sex (apparent anatomic sex of individual, usually determined by gonadal sex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What genetic determinant promotes testis differentiation?

A

Sex-determining Region of the Y chromosome (SRY)

Makes Testis Determining Factor (TDF)

Females lack SRY gene, therefore their gonads do not receive a signal for testicular development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Can you develop ovaries if you only have one X chromosome?

A

No. Two X chromosomes are required for the active genetic pathways necessary for ovarian development

XO (Turner’s syndrome) —> ovarian dysgenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

During the first ________ of gestational life, gonads are indifferent or bipotential

A

5 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In genetic males, the ______ gene of the ____ chromosome produces ______ which influences gonadal development into testis during gestational weeks _____.

A

SRY gene
Y chromosome
TDF
Weeks 6-7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

If TDF does not initiate the development of testes, female gonads (ovaries) begin to develop at what gestational age?

A

Week 9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Testes develop with what three cell types?

A

Germ cells (spermatogonia)

Sertoli cells (produce anti-Müllerian factor)

Leydig cells (produce testosterone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Ovaries develop with what three cell types?

A

Germ cells (oogonia)

Granulosa cells (produce estradiol)

Theca cells (produce androgens and progesterone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

________ differentiate into male reproductive tract and _______ differentiate into female reproductive tract

A

Wolffian ducts —> male

Müllerian ducts —> female

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

As testes develop, they secrete _________ from Sertoli cells and _________ from Leydig cells

A

Anti-Müllerian hormone from Sertoli cells

Testosterone from Leydig cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

________ promotes differentiation of the Wolffian ducts into the internal genitalia —> epididymis, vas deferens, seminal vesicles, and ejaculatory ducts

A

Testosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

________ causes atrophy of the Müllerian ducts, which would have become the female genital tract if they were not suppressed

A

Anti-Müllerian Hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

____________ stimulates the differentiation of the external genitalia around gestational week ________.

A

Dihydrotestosterone (DHT), a testosterone derivative from 5a-reductase

Week 9-10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Without DHT, _________ external genitalia develop

A

Female-like

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Are hormones needed to cause the development of the female gonads?

A

No HORMONES are needed, but development does require two functional X chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In females, the _________ do not regress, giving rise to the ________, _______, and _________.

A

Anti-Müllerian ducts —> Fallopian tubes, uterus, and upper 1/3 of vagina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If a gonadal female is exposed to high levels of androgens in utero, the external genitalia will …

A

Differentiate into a male-like phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

If a fetus lacks the 21-hydroxylase enzyme, what will happen?

A

21-hydroxylase is involved in the biosynthesis of aldosterone and cortisol

Lack of cortisol production —> excessive ACTH —> hyperplasia of adrenal cortex and excessive adrenal androgens

In XX fetuses, ovaries and internal genitalia develop but external genitalia will VIRILIZE —> enlarged clitoris, labial folds appear as an empty scrotum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Most common cause of genital ambiguity

A

21-hydroxylase deficiency

Can lead to life-threatening adrenal insufficiency within the first weeks of life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What’s another name for 21-hydroxylase deficiency?

A

Congenital adrenal hyperplasia

Acne, clitoromegaly, and hirsutism due to adrenal or gonadal androgen excess

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do XY individuals lacking SRY gene develop?

A

Develop as female but NO GONADS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do XX individuals with SRY translocation develop?

A

Develop as male, with testes

Would only known they are XX if you did chromosomal analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do XY individuals with defective AMH production or action develop?

A

Would develop with male external genitalia, but both male and female internal organs, and testes for gonads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How would an XY individual with an absence of testosterone production or action develop?

A

Female-like external genitalia, but no male or female internal tracts, just testes

Usually a lack of receptors (insensitive to testosterone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How would an individual with 5a-reductase deficiency develop?
Would have testes, male internal genitalia but female-like external genitalia (male pseudohemaphrotidism)
26
What would lab findings look like if you had a patient with suspected complete androgen insensitivity syndrome?
``` Testosterone: high-normal DHT: normal FSH and Inhibin: normal LH: high AMH: high Chromosome karyotype: 46XY U/S: no ovaries, no uterus, male testes ```
27
What is the treatment for complete androgen insensitivity syndrome?
Laparoscopic gonadectomy followed by estrogen replacement therapy
28
How is complete androgen insensitivity syndrome diagnosed?
In infancy, due to inguinal masses (undescended testes with nowhere to go) If not infancy, they typically get classified as female at birth and are diagnosed at puberty because of primary amenorrhea
29
When does puberty typically begin?
8-13 years for girls 9-14 years for boys
30
What are the main characteristics of puberty?
Maturation of the hypothalamic-pituitary-gonadal axis —> appearance of secondary sex characteristics, acceleration of growth, and capacity for fertilization
31
Start of puberty in males is marked by ...
Increase in testicular size (gonadarche), followed by development of pubic hair and penile enlargement, as well as increased muscle mass
32
Sperm production and ejaculatory capability are developed in males around ______ years old
13.5 - 13.7 years
33
Adult testicular volume and penile size are achieved by ________
16 years of age
34
Final height in males is reached by _______.
18 years of age
35
Start of puberty in females is marked by _________.
Thelarche (breast development), at 10.9 years on average
36
Typical course of female puberty
Thelarche at ~10.9 —> Pubarche at ~11.2 —> Menarche, usually by 13th birthday
37
The first few menstrual periods for girls are ________, because _______
Non-ovulatory | No positive feedback by estrogen
38
What happens to a girl’s body shape as puberty progresses?
Adipose tissue deposited around the hips Hips enlarge and pelvic inlet widens
39
What hormones are most important in the pubertal growth spurt?
GH and IGF-1
40
In girls, growth spurt begins in ________ and is complete by _________
Early puberty Menarche
41
In boys, growth spurt begins near ________, almost _______ later than girls
Near the end of puberty 2 years later
42
What happens to body composition during puberty?
Men develop 1.5x higher lean body mass, skeletal mass, and muscle mass than women Women develop twice as much fat
43
_____ functions to fuse epiphyses towards the end of puberty in both males and females
Estrogens High levels of estrogen —> shorter stature The longer time to reach puberty in boys accounts for most of the difference in stature
44
Other things that happen during puberty
Bone density increases Periodontal disease may appear (mouth flora changes) Acne appears (testosterone-induced sebaceous gland activity)
45
What is responsible for pubertal timing?
Reactivation of gonadotropin synthesis and secretion • Hypothalamic Maturation Hypothesis - reduction in intrinsic suppression of GnRH • Gonadostat Hypothesis - decreased sensitivity to the negative feedback of estrogen or testosterone INCREASE IN PULSATILE GnRH RELEASE - first occurs during sleep —> increased ratio of LH/FSH release in both sexes that correlates with teh onset of puberty (reverses in late puberty)
46
What is the major determinant in the timing of puberty?
Genetics
47
What are some other factors that influence timing of puberty?
Geographic location Exposure to light Psychological factors General health and nutrition
48
More important than weight in the timing of puberty is ....
Percentage of body fat - from 16-23.5%
49
What is the Leptin theory for the timing of puberty?
Puberty is physiologically gated by the energy resources of the body Delayed puberty in female ballet dancers and accelerated puberty in obese females A metabolic signal from adipose tissue may control onset of sexual maturation Leptin, a protein produce of the obese gene secreted as a hormone from adipose tissue
50
What is the function of Leptin?
Plays an important role in the regulation of body weight and metabolism Plasma levels are correlated with the degree of adiposity and are regulated by fasting and feeding Mutant mice that are unable to produce leptin fail to undergo normal puberty When these mice are given leptin, all aspects of the reproductive system are stimulated and fertility ensues
51
What is the Melatonin Theory of puberty?
Melatonin = hormone secreted from the pineal gland, synchronizes circadian rhythms with light/dark cycles Melatonin inhibits GnRH release**** Puberty may be initiated by a reduction in melatonin secretion
52
What happens if you remove the pineal gland?
Precipitates puberty
53
Precocious Puberty is defined as...
Development of secondary sexual characteristics before age 8 in girls or 9 in boys
54
Gonadotropin-dependent precocious puberty is characterized by...
Increased gonadotropins (LH, FSH) CNS tumors Idiopathic in 90%
55
Gonadotropin-independent precocious puberty is characterized by...
Normal gonadotropins, but increased gonadal hormones Testicular disorders: androgen secreting tumors Ovarian disorders: estrogen secreting tumors 5x more frequent in girls
56
How do you treat Gonadotropin-dependent precocious puberty?
Long-acting GnRH agonists Results in initial release of FSH/LH, followed by down-regulation and desensitization of receptors —> reduced gonadotropins, reduced sex steroids, and biologic effects
57
How do you treat gonadotropin-independent precocious puberty?
Surgical tumor removal
58
Delayed puberty is defined as ...
Lack of physical maturation 2 SD beyond mean onset Can be either hypogonadotropic hypogonadism or hypergonadotropic hypogonadism
59
What is hypogonadotropic hypogonadism?
Gonadotropin deficiency Low gonadotropins —> low gonadal hormones Deficiency of pulsatile release of gonadotropins Ex: Kallman’s Syndrome
60
What is hypergonadatropic hypogonadism?
PRIMARY gonadal failure Low gonadal hormones result in high gonadotropins due to lack of negative feedback (gonadal streak) Ex: Turner’s Syndrome or Klinefelter’s Syndrome
61
Failure of fetal migration of GnRH neurons to the hypothalamus
Kallman’s Syndrome, delayed puberty due to hypogonadotropic hypogonadism Lack of pubertal development, associated with short stature and anosmia
62
Condition associated with anosmia due to a genesis or hypoplastic of the olfactory bulbs and tracts
Kallman’s Syndrome
63
Treatment for Kallman’s Syndrome?
Supplemental sex-steroid (estrogen or testosterone, later GnRH for reproductive capacity)
64
What is Turner’s Syndrome
XO hypergonadotropic hypogonadism Female genital tract forms but no functional gonads Associated with short stature and delayed or absent puberty and amenorrhea A type of primary gonadal failure due to absence of negative feedback
65
What is the treatment for Turner’s Syndrome?
GH first, then supplemental sex steroids
66
Most common form of primary testicular failure
Klinefelter’s syndrome (47, XXY) Due to absence of negative feedback —> feminization
67
Complications of Klinefelter’s syndrome
Germ cell tumors Breast cancer Osteoporosis
68
Treatment for Klinefelter’s Syndrome
GH first and then supplemental sex steroids
69
Increased gonadotropins (LH, FSH) —> increased gonadal hormones
Gonadotropin-dependent precocious puberty
70
Normal gonadotropins (LH, FSH) but increased gonadal hormones
Gonadotropin-independent precocious puberty
71
Low gonadotropins (LH, FSH) result in low gonadal hormones
Hypogonadotropic hypogonadism Kallman’s Syndrome
72
Low gonadal hormones result in high gonadotropins due to lack of negative feedback
Hypergonadotropic hypogonadism Turners and Klinefelters

Phys II Unit III (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions