lecture 4 endocrine system and reproductive system

Question 1

what is the primary and secondary pseudoautosomal region of sex chromosomes?

Answer 1

homologous regions on the X and Y chromosomes

Question 2

what is the critical gene on the Y chromosome that allows for sex differentiation?

Answer 2

SRY gene

Question 3

what develops when the SRY gene is present and when it is absent?

Answer 3

present: testes
absent: ovaries

Question 4

what are the steps for male differentiation?

Answer 4

SRY gene produces TDF at week 5. during week &, testes are formed and produce testosterone and AMH/MIS. the mullarian ducts regress as a result, and the Wolfian ducts develop into the epididymis, vas deferens, seminal vesicles, and ejaculatory duct. Testosterone is converted to DHT by 5 alpha reductase to form male external genetalia

Question 5

what are the steps for femal differentiation?

Answer 5

gonads begin development with DAX1. Mullarian duct becomes: uterus, cervix, upper 1/3 of vagina. ovaries form week 10. In the absense of TDF/SRY/DHT, female external structures will form

Question 6

what structures in male and female external genetalia are analagous?

Answer 6

glans penis ~ glans clitoris
scrotum and prepuce ~ labia majora and prepuce
urethra, perineum, anus ~ urethra, perineum, anus, labia minora

Question 7

androgen insensitivity syndrom

Answer 7

Sex Chromosomes: XY
Abnormality: androgen receptors don’t function (doesn’t recognize T or DHT)
Internal Anatomy: “male” because testes have developed (no Wolfian or Mullerian)
External Anatomy: female
Important fact: testes remain inside (don’t descend)  can turn cancerous

As the name describes, individuals whose bodies simply do not respond to the Androgen/Testosterone signals

Question 8

guevedoces

Answer 8

Sex Chromosomes: XY
Abnormality: no 5-alpha-reductase (T  DHT)
Internal Anatomy: male (Wolfian)
External Anatomy: female born  male at puberty

Individual born looking like a normal baby girl  Masculinze at puberty
Capable of making sperm and ejaculating
Grow facial fair
Enlarged clitoris
Fused labia
Important facts: Society allows these women to spend the rest of their lives as men.

Question 9

Adrenogenital syndrom/congential adrenal hyperplasia

Answer 9

Sex Chromosomes: XX
Abnormality: adrenal gland makes insufficient cortisol and increased andorgens (masculinizing)
Internal Anatomy: female (Mullerian)
External Anatomy: female
Important facts: masculine effects due to T and DHT
fused labia
enlarged clitoris
Facial hair and other secondary male characteristics

If it occurs in males, puberty can start early

Question 10

precocious puberty

Answer 10

Sex Chromosomes: XY
Abnormality: constitutively active LH receptor (high, high, SUPER HIGH amounts of T)
Internal Anatomy: male (Wolfian)
External Anatomy: male
Important facts: undergo puberty (from huge surge in T) very early (4 years old), X-limited disorder = almost always shows up in males)
Penis enlargement
Scrotal development
Facial hair growth, other secondary male characteristics

Autosomal dominant condition, only affects males.