Module 9: Reproductive System Flashcards Preview

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Flashcards in Module 9: Reproductive System Deck (224)
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1

• process of genetic inheritance that sets the gender of an individual at the moment of fertilization

SEX DETERMINATION

2

• development of differences between males and females from an undifferentiated zygote

SEX DIFFERENTIATION

3

• sequential processes of establishment of sex and sexual difference
• includes the processes that determine:
o CHROMOSOMAL or GENETIC SEX
o GONADAL SEX
o PHENOTYPIC or GENITAL SEX
o PSYCHOLOGICAL SEX

Sex Determination and Differentiation

4

• established by genetic inheritance at the moment of fertilization

Chromosomal Sex

5

• development of primary sex organs (gonads) in response to genetic sex
• If you are a male/female, you should have an organ that tells you that your a male/female (testis/ovary)

Gonadal Sex

6

• a chromosome that determines the maleness

Y chromosome

7

Gonadal Sex (Male)

Sex-determining region of Y chromosome (SRY) codes for production of testis-determining factor (TDF) >> TDF directs differentiation of gonads into TESTES

8

Gonadal Sex (Female)

No Y chromosome >> No, Sex-determining region of Y chromosome (SRY) and testis-determining factor (TDF) >> undifferentiated gonads develop into OVARIES

9

• regulation by gonadal sex of the differentiation of the genital apparatus
• influenced mainly by genetics and hormonal factors
• determines by the presence or absence of a masculinizing hormone (testosterone)

Phenotypic or Genital Sex

10

• secretes testosterone and Mullerian-inhibiting factor (anti-mullerian hormone)
• transforms Wolffian ducts into internal male reproductive system
• can be converted to dihydrotestosterone that promotes the development of undifferentiated external genitalia among male lines (penis, scrotum)

Testosterone

11

• where the development of the internal female reproductive tract came from (eg Oviducts, Uterus)

Mullerian duct

12

• causes the degeneration of the Wolffian ducts and development of undifferentiated external genitalia along female lines (eg Clitoris, labia)

Absence of Testosterone

13

• establishment of gender role, gender identity or sexual orientation
• influenced by behavioral and cultural factors

Psychological Sex

14

• determined at time of fertilization when ovum and sperm unite
*genetic male (heterogametic ) = XY pattern
*genetic female (homogametic) = XX pattern

• mutation of genes on an X chromosome results in transmission of X-linked traits
*EXAMPLES: hemophilia, color blindness

Genetic Sex

15

• presence of the Y chromosome is the single most consistent determinant of maleness

*contains SRY gene responsible for sex determination
*necessary for testes and masculine genital pattern development

Genetic Sex

16

• presence of additional X chromosome does not alter fundamental maleness dictated by the Y chromosome
*EXAMPLE: Klinefelter Syndrome (XXY)

Genetic Sex

17

• discovered by Barr and Bertram in 1949
• one of the two copies of the X chromosome present in females is inactivated (Lyon hypothesis)
*nucleus of somatic cells of females contain a plano-convex mass adherent to inner side of nuclear membrane (sex chromatin mass or Barr body)

Sex Chromatin Test

18

(Sex Chromatin Test)
• presence of 1 Barr body means that an individual has 1 X chromosome in excess (2 X chromosomes total)

Normal Female

19

(Sex Chromatin Test)
• presence of 2 Barr bodies means that an individual has 2 X chromosomes in excess (3 X chromosomes total)

Superfemale

20

Specimens for Sex Chromatin Test

• NERVE CELLS
• BUCCAL SMEAR (inner cheek scrapings)
- if 20% positive, genetic female
- if 0-4% positive, genetic male (4% error margin)
• BLOOD SMEAR
- presence of drumstick appendage in nucleus of neutrophils in genetic females
- low positiveness (6/500 neutrophils)
• VAGINAL SMEAR

21

• form of genetic imprinting where one of the two chromosome is inactivated so that the only one is active

Lyonization

22

• pluck 3-4 strands of normal scalp hair
- tease the root of hair
- stain with fluorescent stain
- look for fluorescent body (Y body)
- part of the Y chromosome present only in males (15/100 cells) and invariably absent in females

Hair Root Test

23

• noninvasive screening for large populations in sports competitions (eg, Olympics)
- assurance that individual joining female division sports competition is a normal genetic female

Hair Root Test

24

• patient has a testes and produce testosterone but despite the presence of it, it lacks of receptor for testosterone
• due to high testosterone, pt is masculine
• pt is genetically male but due to the absence of penis, pt can be mistaken as a female

Androgen Insensitivity Syndrome

25

• requires use of tissue culture (may take 10 days for complete processing)
• most accurate method (gold standart)
• done by geneticists
• required for patients who will undergo gender reassignment surgery (genetic sex must be determine for those who want gender reassignment or those with ambiguous genitalia)

Karyotyping

26

What are the 3 tests for genetic sex?

• Sex Chromatin Test
• Hair Root Test
• Karyotyping

27

• development of primitive gonad into either testes or ovary
- outer cortex composed of COELOMIC EPITHELIAL CELLS
- inner medulla composed of STROMAL MESENCHYME which surrounds cords of epithelial cells

• at 4th to 6th week of gestation, all embryos have bipotential gonads (potential to differentiate along either male or female lines)

Gonadal Sex

28

Testis-determining SRY protein initiates the production of multiple gonad medulla to differentiate into a testis which has __.

*In males, only medulla will develop and the cortex will regress.

Leydig Cells and Sertoli Cells

29

• secrete testosterone which controls the development of Wolffian duct into accessory structures and development of external genitalia via DHT

Leydig Cells

30

• secrete Anti-mullerian hormone that causes regression of Mullerian duct; responsible for the nutrition of the spermatogonia

Sertoli Cells