Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL155 > Sex Determination and Development > Flashcards

Sex Determination and Development Flashcards

1
Q

Differentiate the terms sex, gender, and sexuality

A

Sex = what a person has (morphological sex/gonads)
Gender = who a person identifies as
Sexuality = who a person likes/loves

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

What are the components of sex

A
  1. Morphological sex = what is visible (external genitalia)
  2. Primary sex characteristics: changes to the sexual organs themselves (uterus, vagina, penis, and testes)
  3. Secondary sex characteristics: other visible changes that mark adult maturation such as changes in height and body shape
  4. Gonads = reproductive organs (testes or ovaries)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Give some examples of primary sex characteristics (male/female)

A
  • production of gametes
  • growth of reproductive organs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Give some examples of secondary sex characteristics (male/female)

A
  • growth of pubic hair
  • facial hair
  • voice deepening for men
  • breast development
  • hips widening
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are gonads

A

male = testes -> produces smaller gametes (sperm)
female = ovaries -> produces larger gametes (eggs)

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

What are intersex characteristics

A

Sex is not a binary property
- characteristics can fall between the common ranges for male and female
- conditions for Diverse Sexual Development (DSD) are another term used for intersex conditions
- characteristics that lie somewhere between the male and female sex

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

Differentiate morphological sex from chromosomal sex

A

Morphological sex refers to what is visible (may be external reproductive organs)

Chromosomal sex refers to the sex chromosomes present in the somatic cells

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

What is chromosomal sex

A

Sex defined by the sex chromosomes present in somatic (non-germline) cells

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

What is the combination for male chromosomal sex

A

XY
- only males have a Y chromosome

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

What is the combination for female chromosomal sex

A

XX

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

How many pairs of autosomes do humans carry

A

Humans have 22 pairs of autosomes and normally 1 pair of sex chromosomes in diploid cells

Diploid = contains two sets of chromosomes (somatic cells)
Haploid = contain one set of chromosomes (gametes)

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

Is the Y or X chromosome primarily responsible for determining sex

A

Sex is primarily determined by the Y chromosome
- most individuals will have an X chromosome, but the primary sex characteristics are determined by the presence of the Y chromosome
- if the Y chromosome is present, it sets the development for gonadal sex (male genitalia/gonads)

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

What gene is responsible for initiating the cascade of male-typical sex development

A

SRY

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

What is the role of SRY and where can it be found

A

SRY is a gene on the Y-chromosome
- responsible for initiating the cascade of male-typical sex development
- this gene transcribes/activates other genes/proteins that drive the development of other male sex characteristics

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

What happens when SRY is mutated/changed

A

This is most evident in DSDs where the critical role of SRY becomes prevalent

  • when specific changes occur to SRY, this can cause DSDs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain what is expressed in each of the following scenarios:

Female = XX

Male = XY

Female = XY
- XY female with SRY gene missing

Male
- XX male with SRY

A

Female = XX
- expresses characteristics of a female

Male = XY
- expresses characteristics of a male

Female = XY
- XY female with SRY gene missing
- female sex development because the Y chromosome has some kind of mutation that causes the SRY gene to be missing
- even though the person has a Y chromosome, they will not express male characteristics because the SRY gene is missing

Male
- XX male with SRY
- X chromosome expresses SRY because of some mixing up that occurred during meiosis (gamete formation)
- develops male characteristics even though they have XX chromosomes

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

What is gonadal sex

A

Defined by the anatomy of the gonad, which determines which type of gametes are produced
- either sperm or eggs

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

How does gonadal sex differ from morphological sex and chromosomal sex

A

Gonadal sex refers to the anatomy of the gonads and type of gametes produced

Morphological sex refers to the external genitalia? and physical characteristcs (what is visible)

Chromosomal sex refers to the combination of sex chromosomes in somatic cells (and SRY gene)

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

What are the two types of gonads and their respective gametes produced

A
  1. Testes
    - produces sperm
    - smaller gametes
  2. Ovaries
    - produces ova (eggs)
    - larger gametes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

All embyros have two undifferentiated gonads and two sets of internal ducts at early developmental stages:

What is this stage called

A

the INDIFFERENT stage

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

What is the name of the two ducts that all embryos have during the indifferent stage

A
  1. Woffian duct
  2. Mullerian duct
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define what bipotential gonad means

A

Because embyros start in the indifferent stage where they hae two undifferentiated gonads and two sets of internal ducts, they are considered bipotential
- they have the potential to develop into testes or ovaries
- based on the presence or absence of SRY gene

23
Q

All mature gonads have three functional cell classes even though they differ in their exact physiological and anatomical properties: What are these three functional cell classes

A
  1. Steroid-secreting cells
  2. Support “nurse” cells
  3. Germ cells
24
Q

What are steroid-secreting cells

A

responsible for the secretion of steroid hormones

in females = estrogen
in males = testosterone

25
Q

What are support “nurse” cells

A
26
Q

What are germ cells

A

sex cells (eggs and sperm) that sexually reproducing organisms use to pass on their genomes from one generation to the next

in females = oocyte
in males = spermatogonia

27
Q

Differentiate SRY- and SRY+

A

SRY- = without SRY, ovarian determining genes are expressed
= ovaries

SRY+ = with SRY, initiates cascade which leads to the expression of testes determining factors
= testes

28
Q

What is SOX9

A

A testes determining factor
- activation of SOX9 occurs when the SRY gene is present
- regulates the development of other male genes

29
Q

The three functional classes of cells in gonads have different names in both ovaries and testes: What are they called in testes

A

Support cells = Sertoli cells
Steroid-secreting cells = Leydig cells
Germ cells = spermatogonia

30
Q

The three functional classes of cells in gonads have different names in both ovaries and testes: What are they called in ovaries

A

Support cells = granulosa
Steroid-secreting cells = follicular cells (granulosa and germ cells)
Germ cells = oocyte

31
Q

What is the role of anti-Mullerian hormone (AMH) in the testes

A

Support cells in the testes (Sertoli cells) secrete anti-Mullerian hormone (AMH) which leads to the male typical development of ducts

32
Q

Describe the difference between AMH+ and AMH-

A

From a bipotential gonad/indifferent stage:

AMH+
= AMH degrades Mullerian ducts
= Wolffian ducts develop forming male internal genitalia

AMH-
= no AMH produced
= Mullerian ducts develop and form female internal genitalia (oviduct/Fallopian tubes)
= Wolffian ducts degrade

33
Q

During male gonadal development, which duct degrades

During female gonadal development, which duct degrades

A

Male = Mullerian ducts degrade

Female = Wolffian ducts degrade

34
Q

Which of the following embryonic structures eventually forms the uterus

  1. Genital ridge
  2. Wolffian duct
  3. Mullerian duct
  4. Hindgut
A

Uterus = female reproductive organ

ANSWER: Mullerian duct

35
Q

Differentiate the role of steroid-secreting cells in the ovaries and testes

A

XX
= ovaries
= follicular cells (granulosa and germ cells)
= secretes mostly estrogen (androgen/progesterone)

XY
= testes
= Leydig cells (Sertoli and germ cells)
= secretes mostly testosterone (androgen)

36
Q

Recall: What are steroid hormones

A

Class 3 lipid derivatives
- derivative of cholesterol
- hydrophobic
- lipid-soluble

37
Q

What are the five classes of steroid hormones receptors

A
  1. Mineralcorticoids (MR)
  2. Glucocorticoids (GR)
  3. Estrogens (ER)
  4. Androgens (AR)
  5. Progesterone (PR)
38
Q

True or False:

All hormones are precursors to another hormone

A

FALSE

  • only SOME hormones are precursors to other hormones
39
Q

True or False:

Converting enzymes can be found in non-endocrine tissues

A

TRUE

  • converting enzymes can be expressed in other tissues that are non-endocrine
40
Q

True or False:

All steroid hormone reactions are irreversible

A

FALSE

  • NOT ALL, but many reactions are irreversible
  • only go in one direction
41
Q

Which cells would you expect to express the enzyme 17B-HSD if this enzyme produces androgens

A
  1. Leydig cells in the testes
  2. Follicular cells in the ovary
42
Q

Which cells would you expect to express the enzyme 21-hydroxylase if this enzyme produces glucocorticoids/mineralocorticoids

A
  1. Zona fasciculata cells in the adrenal cortex
    - produce glucocorticoids (cortisol)
    - from adrenal cortex
43
Q

What is morphological/anatomical sex

A

Defined by the anatomy of the external genitalia
- which develop in response to androgen receptor signalling

44
Q

When do external genitalia begin to develop

A

at 9 weeks of fetal development

45
Q

How does female external genitalia development differ from male external genitalia development

A

Leydig cels in testes produce testosterone and dihydrotestosterone which cause the development of male external genitalia

Meanwhile, follicular cells in ovaries do not produce gonadal steroids, which is what causes the female external genitalia to develop

46
Q

Sex hormones can also be found outside the reproductive system - Name another place it can be found

A

Within parts of the brain
- key receptors for both ER and AR expression are subnuclei within the hypothalamus and amygdala

47
Q

What is the enzyme aromatase

A

Converts androgens to estrogens

48
Q

During puberty, gonadal hormone levels rise in both sexes, initiating processes of sexual maturation
- secretions of which hormone from the hypothalamus is increased

A

hypothalamus increases GnRH production
- FSH => gamete production initiated
- LH => sex hormones are released, initiating secondary sex characteristics and behaviour

49
Q

What causes the development of secondary sex characteristics

A

Elevated levels of testicular or ovarian hormones

50
Q

Describe some secondary sex characteristics in males caused by elevated levels of testosterone

A
  • body hair growth
  • bone growth
  • myofibre hypertrophy
  • activational effects on sex drive and sexual behaviours
  • increased RBC production
  • growth of larynx and vocal cords
  • development of accessory structures and sperm production
51
Q

Describe some secondary sex characteristics in females caused by elevated levels of estrogen

A
  • body hair growth
  • development of mammary glands (breast tissue)
  • bone growth
  • some myofibre hypertrophy
  • activational effects on sex drive and sexual behaviours
  • reduced blood cholesterol levels
  • development of uterine lining (period) and accessory reproductive structures
52
Q

Which hormone is the main testicular secretion

A

Testosterone

53
Q

Which hormone is the main ovarian secretion

A

Estrogen

BIOL155 (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions