Reproduction and sexual differentiation

Question 1

Diagram and explain the important steps in mitosis

Answer 1

Question 2

diagram and explain the important steps in meiosis for male

Answer 2

Question 3

diagram and explain the important steps in meiosis for females

Answer 3

Question 4

what occurs if sexual differentiation is interupted?

Answer 4

1. true hermaphrodites
   
   1. individuals who have both male and femal gonads
2. pseudor hermaphrodites
   
   1. individuals with the gonads of one sex abut external genitalia of the opposite sex or both sexes

Question 5

What is the important component on the Y c’some? What does it lead to the devlopment of?

Answer 5

1. SRY(sex-determining region of y chromosome) region
   
   1. located on the short arm of Y chromosome
   2. contains the testis determining factor (TDF) on the short arm of the Y chromosome
      
      1. allows the development of the testes
2. X chromosome has gene that encodes for androgen receptors
   
   1. lead ot primary sec characteristics
3. must have both the androgen and its receptor to have action of the hormone on the target tissue
4. genital ridges within the fetus give rise to the indifferent gonads ~6 weeks

Question 6

What contributes the androgen receptor? What is it responsible for?

Answer 6

1. SRY(sex-determining region of y chromosome) region
   
   1. located on the short arm of Y chromosome
   2. allows the development of the testes
2. X chromosome has gene that encodes for androgen receptors
   
   1. lead ot primary sex characteristics
      
      1. ​gonads
      2. accessory sex organs-storing
3. must have both the androgen and its receptor to have action of the hormone on the target tissue
4. genital ridges within the fetus give rise to the indifferent gonads ~6 weeks

Question 7

what must be present for the proper action on the target tissue?

Answer 7

1. SRY(sex-determining region of y chromosome) region
   
   1. located on the short arm of Y chromosome
   2. allows the development of the testes
2. X chromosome has gene that encodes for androgen receptors
   
   1. lead ot primary sec characteristics
3. must have both the androgen and its receptor to have action of the hormone on the target tissue
4. genital ridges within the fetus give rise to the indifferent gonads ~6 weeks

Question 8

What important process occurs in the fetus ~week 6?

Answer 8

1. SRY(sex-determining region of y chromosome) region
   
   1. located on the short arm of Y chromosome
   2. allows the development of the testes
2. X chromosome has gene that encodes for androgen receptors
   
   1. lead ot primary sec characteristics
3. must have both the androgen and its receptor to have action of the hormone on the target tissue
4. genital ridges within the fetus give rise to the indifferent gonads ~6 weeks
   
   1. ​occurs regarless of genetic makeup
      2.

Question 9

what is present in an early embryo regarless of sex?

Answer 9

1. early embryo has
   
   1. wolffian duct
      
      1. future male internal reproductive tract
   2. mullerian duct
      
      1. future female internal reproductive tract
2. Testes develop from testes determining factor on the SRY region of the short arm of the Y c’some
   
   1. development of testes is required to actively stimulate Wolffian duct formation into male redproductive tract

Question 10

what is absolutly necessary for Wolffian duct formation?

Answer 10

1. early embryo has
   
   1. wolffian duct
      
      1. future male internal reproductive tract
   2. mullerian duct
      
      1. future female internal reproductive tract
2. Testes develop from testes determining factor(TDF) on the SRY region of the short arm of the Y c’some
   
   1. development of testes is required to actively stimulate Wolffian duct differentiation into male redproductive tract
   2. Testosterone acts in a paracrine manner. Needs testosterone from the testes to differentiate the wolffian duct into​​
      
      1. ​epididymis
      2. vas deferens
      3. seminal vesicles
      4. ejaculatory duct

Question 11

explain the hormones that differentiate the embryo gonads to the male direction. where are they sourced from?

Answer 11

1. development of male internal genitalia depends on two hormones produced by fetal testis
   
   1. testosterone
      
      1. from leydig cells
   2. amullerian inhibitin hormone =anti-mullerian hormone
      
      1. from sertoli cells
2. indifferent gonad ahas an outer cortex and inner medullary region
   
   1. testis develop from the medulla
   2. cortex regresses to become the leydig cells
3. 1st 5 week in-utero gonads of males and females have two cells types coelomic and mesenchymal stromal
   
   1. coelmic->sertoli cells
   2. mesenchymal stromal ->Leydig cells
4. primoridial germ cell migration fro mthe cortex t othe primitive sex cord of medulla
   
   1. stimulates formation of
      
      1. semineferous tubules
      2. sertoli cell differentiation, enclose germ cells

Question 12

describe the differentiation with regard to regions of the primordial gonads.

Answer 12

1. development of male internal genitalia depends on two hormones produced by fetal testis
   
   1. testosterone
      
      1. from leydig cells
   2. amullerian inhibitin hormone =anti-mullerian hormone
      
      1. from sertoli cells
2. indifferent gonad has an outer cortex and inner medullary region
   
   1. testis develop from the medulla
   2. cortex regresses to become the leydig cells
3. 1st 5 week in-utero gonads of males and females have two cells types coelomic and mesenchymal stromal
   
   1. coelmic->sertoli cells
   2. mesenchymal stromal ->Leydig cells
4. primoridial germ cell migration fro mthe cortex t othe primitive sex cord of medulla
   
   1. stimulates formation of
      
      1. semineferous tubules
      2. sertoli cell differentiation, enclose germ cells

Question 13

How many cell types are present in 5week old fetus? explain the differentation from areas

Answer 13

1. development of male internal genitalia depends on two hormones produced by fetal testis
   
   1. testosterone
      
      1. from leydig cells
   2. amullerian inhibitin hormone =anti-mullerian hormone
      
      1. from sertoli cells
2. indifferent gonad ahas an outer cortex and inner medullary region
   
   1. testis develop from the medulla
   2. cortex regresses to become the leydig cells
3. 1st 5 week in-utero gonads of males and females have two cells types coelomic and mesenchymal stromal
   
   1. coelmic->sertoli cells
   2. mesenchymal stromal ->Leydig cells
4. primoridial germ cell migration fro mthe cortex t othe primitive sex cord of medulla
   
   1. stimulates formation of
      
      1. semineferous tubules
      2. sertoli cell differentiation, enclose germ cells

Question 14

cell migration from the cortex to medulla has what effect on the organ/organism?

Answer 14

1. development of male internal genitalia depends on two hormones produced by fetal testis
   
   1. testosterone
      
      1. from leydig cells
   2. amullerian inhibitin hormone =anti-mullerian hormone
      
      1. from sertoli cells
2. indifferent gonad ahas an outer cortex and inner medullary region
   
   1. testis develop from the medulla
   2. cortex regresses to become the leydig cells
3. 1st 5 week in-utero gonads of males and females have two cells types coelomic and mesenchymal stromal
   
   1. coelmic->sertoli cells
   2. mesenchymal stromal ->Leydig cells
4. primoridial germ cell migration from the cortex of the primitive sex cord of medulla
   
   1. stimulates formation of
      
      1. semineferous tubules
      2. sertoli cell differentiation, enclose germ cells

Question 15

describe the route and process of development in the absence of testosterone

Answer 15

1. in the absence of testosterone
   
   1. wolffian ducts regress
   2. mullerian ducts become
      
      1. fallopian tubes
      2. uterus
      3. cervix
      4. upper 1/3 of vagina
2. indifferent gonad has an outer cortex and inner medullary region
   
   1. ovary develops from cortex and medulla regresses
3. 1st week in-utero of males and females indifferent and have 2 types of cells
   
   1. coelomic ->granulosa
   2. Mesenchymal stromal ->theca
4. differentiation into female
   
   1. no testosterone
      
      1. wolfian duct regression
      2. mullarian duct differentiation
         
         1. uterine tubes
         2. uterus
         3. cervix
         4. upper 1/3 of the vagina
   2. gonads
      
      1. cortex grows, medulla regresses
      2. both X’s are active
      3. germ cells under go mitosis
         
         1. oogonia increase in population
      4. oogonia undergo meiosis
         
         1. arrest in Prophase 1
      5. cortex, granulosa cells and stroma curround the oogonia
      6. stroma differentiates into theca cells

Question 16

Describe the route of wolfian duct regression and mullarian duct differentiation

Answer 16

1. in the absence of testosterone
   
   1. wolffian ducts regress
   2. mullerian ducts become
      
      1. fallopian tubes
      2. uterus
      3. cervix
      4. upper 1/3 of vagina
2. indifferent gonad has an outer cortex and inner medullary region
   
   1. ovary develops from cortex and medulla regresses
3. 1st week in-utero of males and females indifferent and have 2 types of cells
   
   1. coelomic ->granulosa
   2. Mesenchymal stromal ->theca
4. differentiation into female
   
   1. no testosterone
      
      1. wolfian duct regression
      2. mullarian duct differentiation
         
         1. uterine tubes
         2. uterus
         3. cervix
         4. upper 1/3 of the vagina
   2. gonads
      
      1. cortex grows, medulla regresses
      2. both X’s are active
      3. germ cells under go mitosis
         
         1. oogonia increase in population
      4. oogonia undergo meiosis
         
         1. arrest in Prophase 1
      5. cortex, granulosa cells and stroma curround the oogonia
      6. stroma differentiates into theca cells

Question 17

what occurs in the coelomic and mesechymal stromal cells for female development?

Answer 17

1. in the absence of testosterone
   
   1. wolffian ducts regress
   2. mullerian ducts become
      
      1. fallopian tubes
      2. uterus
      3. cervix
      4. upper 1/3 of vagina
2. indifferent gonad has an outer cortex and inner medullary region
   
   1. ovary develops from cortex and medulla regresses
3. 1st week in-utero of males and females indifferent and have 2 types of cells
   
   1. coelomic ->granulosa
   2. Mesenchymal stromal ->theca
4. differentiation into female
   
   1. no testosterone
      
      1. wolfian duct regression
      2. mullarian duct differentiation
         
         1. uterine tubes
         2. uterus
         3. cervix
         4. upper 1/3 of the vagina
   2. gonads
      
      1. cortex grows, medulla regresses
      2. both X’s are active
      3. germ cells under go mitosis
         
         1. oogonia increase in population
      4. oogonia undergo meiosis
         
         1. arrest in Prophase 1
      5. cortex, granulosa cells and stroma curround the oogonia
      6. stroma differentiates into theca cells

Question 18

list the female differentiation for the duct and gonads

Answer 18

1. in the absence of testosterone
   
   1. wolffian ducts regress
   2. mullerian ducts become
      
      1. fallopian tubes
      2. uterus
      3. cervix
      4. upper 1/3 of vagina
2. indifferent gonad has an outer cortex and inner medullary region
   
   1. ovary develops from cortex and medulla regresses
3. 1st week in-utero of males and females indifferent and have 2 types of cells
   
   1. coelomic ->granulosa
   2. Mesenchymal stromal ->theca
4. differentiation into female
   
   1. no testosterone
      
      1. wolfian duct regression
      2. mullarian duct differentiation
         
         1. uterine tubes
         2. uterus
         3. cervix
         4. upper 1/3 of the vagina
   2. gonads
      
      1. cortex grows, medulla regresses
      2. both X’s are active
      3. germ cells under go mitosis
         
         1. oogonia increase in population
      4. oogonia undergo meiosis
         
         1. arrest in Prophase 1
      5. cortex, granulosa cells and stroma curround the oogonia
      6. stroma differentiates into theca cells

Question 19

list the ways that sex hormones are transported in the blood system

Answer 19

1. Testosterone and estrogen bind and are transported through two chaperones
   
   1. sex steroid binding globulin(SSBG)
   2. Albumin
2. progesterone is transported by
   
   1. corticosteroid binding globulin (CBG)
3. half life of steroids ~30-60 minutes

Question 20

Describe and diagram the route of sex steroids on a cell

Answer 20

1. hydrophobic
   
   1. SSBG, albumin or CBG
2. binds to a protein in the cytoplasm and then transports into the nucleus
3. once int he nucleus, it acts as a transcription factor

Question 21

diagram and explain the synthesis of sex steroids in the testes and ovaries

Answer 21

Question 22

describe the formation of testosterone and use in the gonads vs adrenal gland

Answer 22

1. gonads-male
   
   1. leydig cells-5 steps from cholesterol to testosterone
      
      1. uses 17b-hydroxysteroid dehydrogenase
      2. cholesterol(27)->prenenalone(21)->17-1Hpreg. ->DHEA (19) -> androstenedol ->testosterone
   2. sertoli cells
      
      1. uses aromatase
      2. testosterone(19) -> estrogen(18)
   3. target cells
      
      1. 5alpha-reductase is located in the target cell and converts tetsosterone to DHT
2. adrenal gland
   
   1. uses desmolase to generate testosterone. During times of stress, this pathway is not favored, rather cortisol synthesis is preffered.

Question 23

where is aromatase active in the male?

Answer 23

1. gonads-male
   
   1. leydig cells-5 steps from cholesterol to testosterone
      
      1. uses 17b-hydroxysteroid dehydrogenase
      2. cholesterol(27)->prenenalone(21)->17-1Hpreg. ->DHEA (19) -> androstenedol ->testosterone
   2. sertoli cells and adipocytes
      
      1. uses aromatase
      2. testosterone(19) -> estrogen(18)
   3. target cells
      
      1. 5alpha-reductase is located in the target cell and converts tetsosterone to DHT
2. adrenal gland
   
   1. uses desmolase to generate testosterone. During times of stress, this pathway is not favored, rather cortisol synthesis is preffered.

Question 24

what leads to the generation of secondary male sex characteristics and what are those characteristics

Answer 24

1. development of primary sex characteristics is under the influence of hormones produced by the gonads in-utero
   
   1. gonads->testes due to expression of TDF
      
      1. sertoli->antim ullarian hormone
         
         1. mullerian duct regression
      2. leydig cells->testosterone
         
         1. accessory sex organs: epididymus, vas deferens, seminal vesicles and ejaculatory duct.
            
            1. originate from the wolffian duct
2. secondary sex characteristics are under the influence of DHT
   
   1. prostate
   2. penis
   3. scrotum

Question 25

describe the flow of male sexual differentiation of the internal duct and the hormones that lead to this outcome

Answer 25

1. development of primary sex characteristics is under the influence of hormones produced by the gonads in-utero
   
   1. gonads->testes due to expression of TDF
      
      1. sertoli->antim ullarian hormone
         
         1. mullerian duct regression
      2. leydig cells->testosterone
         
         1. accessory sex organs: epididymus, vas deferens, seminal vesicles and ejaculatory duct.
            
            1. originate from the wolffian duct
2. secondary sex characteristics are under the influence of DHT
   
   1. prostate
   2. penis
   3. scrotum

Question 26

expression of the following in the fetus lead to devleopment of what structures?

1. mullerian inhibiting hormone
2. testosterone
3. dihydrotestosterone

Answer 26

1. development of primary sex characteristics is under the influence of hormones produced by the gonads in-utero
   
   1. gonads->testes due to expression of TDF
      
      1. sertoli->antim ullarian hormone
         
         1. mullerian duct regression
      2. leydig cells->testosterone
         
         1. accessory sex organs: epididymus, vas deferens, seminal vesicles and ejaculatory duct.
            
            1. originate from the wolffian duct
2. secondary sex characteristics are under the influence of DHT- around week9-10 of gestation
   
   1. prostate
   2. penis
   3. scrotum

Question 27

DHT generation occurs due to what enzyme? what characteristics occur as a result?

Answer 27

1. phenotypic differentiation
   
   1. external genitalia of both genders begins to differentiate at 9-10 weeks
   2. the common linage for the genitalia differentiate based on the presence of DHT.
   3. The enzyme responsible for the reaction of testosterone->DHT is 5alph reductase.

Question 28

when does phenotypic differentiation occur? explain the hormone involved, how it works and the female vs male and common tissues.

Answer 28

1. phenotypic differentiation
   
   1. external genitalia of both genders begins to differentiate at 9-10 weeks
   2. the common linage for the genitalia differentiate based on the presence of DHT.
   3. The enzyme responsible for the reaction of testosterone->DHT is 5alph reductase.

Question 29

describe the following for normal male and femal development

1. gonad
2. mullarian duct
3. wollfian duct
4. external genitalia

Answer 29

Question 30

a patient presents with the following 45,X. Describe the following

1. genetic state
2. gonad
3. mullarian duct
4. wollfian duct
5. external genitalia

Answer 30

Question 31

Explain the testes and internal tract of a patient with androgen insensitivity syndrome (morris syndrome)

Answer 31

this is androgen insensitivity syndrome

1. x-linked recessive defect that leads to teh absence of androgen receptors on target tissues
2. testes do not descend - can still produce testosterone, but it not seen by the duct
   
   1. end up as a primitive location where leydig cells are actively producing testosterone, but not well formed
3. no internal tract
   
   1. wolfian duct did not develop b/c no response to
4. during puberty
   
   1. HPA axis kicks on for male -> increasing testosterone
   2. no active receptors-> build up of testosterone
   3. adipocytes and adrenal glands have aromatase still active
      
      1. genrating estrogen.

Question 32

Explain why a patient with morris syndrome grows up to look like a woman, even though they have a genotype of XY.

Answer 32

this is androgen insensitivity syndrome

1. x-linked recessive defect that leads to teh absence of androgen receptors on target tissues
2. testes do not descend - can still produce testosterone, but it not seen by the duct
   
   1. end up as a primitive location where leydig cells are actively producing testosterone, but not well formed
3. no internal tract
   
   1. wolfian duct did not develop b/c no response to
4. during puberty
   
   1. HPA axis kicks on for male -> increasing testosterone
   2. no active receptors-> build up of testosterone
   3. adipocytes and adrenal glands have aromatase still active
      
      1. genrating estrogen.

Question 33

A patient has a mutation leading to the inability to respond to testosterone. Describe the following.

1. genetic state
2. gonads
3. mullarian duct
4. wollfian duct
5. external genitalia

Answer 33

this is androgen insensitivity syndrome

1. x-linked recessive defect that leads to teh absence of androgen receptors on target tissues
2. testes do not descend - can still produce testosterone, but it not seen by the duct
   
   1. end up as a primitive location where leydig cells are actively producing testosterone, but not well formed
3. no internal tract
   
   1. wolfian duct did not develop b/c no response to
4. during puberty
   
   1. HPA axis kicks on for male -> increasing testosterone
   2. no active receptors-> build up of testosterone
   3. adipocytes and adrenal glands have aromatase still active
      
      1. genrating estrogen.

Question 34

A patient suffers from a mutation leading to a decrease in testosterone generation. Describe th following

1. genetic state
2. gonadal development
3. mullarian duct
4. wollfian duct
5. external genitalia

Answer 34

Question 35

what is the outcome for a male patient with a mutaion in the enzyme generating DHT?

1. genetic state
2. gonad
3. mullarian duct
4. wollfian duct
5. external genitalia

Answer 35

Question 36

5 alpha reductase is on what c’some?

Answer 36

X chromosome

Question 37

is the SRY portion of the Y chromosome active and working in a patient with AIS?

Answer 37

1. MIH(AMH)
   
   1. present -> desrtruction of the mullerian duct
2. testosterone
   
   1. VERY HIGH
   2. insesitivity leads to no development of the primary sex characteristics
      
      1. epidiymis, vas deferens, seminal vesicle
3. DHT
   
   1. present
   2. insensitivity leads to no developmentof the secondary sex characteristics
      
      1. prostate, penis and scrotum
4. estrogen
   
   1. present and very high
   2. aromatase in the adipocytes and adrenal glands is activly converting all the testosterone into estrogen

Question 38

describe the presence in A patient with morris syndrome (AIS).

1. MIH(AMH)
2. testosterone
3. DHT
4. estrogen

Answer 38

1. MIH(AMH)
   
   1. present -> desrtruction of the mullerian duct
2. testosterone
   
   1. VERY HIGH
   2. insesitivity leads to no development of the primary sex characteristics
      
      1. epidiymis, vas deferens, seminal vesicle
3. DHT
   
   1. present
   2. insensitivity leads to no developmentof the secondary sex characteristics
      
      1. prostate, penis and scrotum
4. estrogen
   
   1. present and very high
   2. aromatase in the adipocytes and adrenal glands is activly converting all the testosterone into estrogen