Repro 1 Flashcards
Role of reproduction
Making new humans
Why are we advanced when it comes to reproduction
- Mate for pleasure and procreation
- Does not only occur during “fertile” periods
Sexually dimorphic
Males and females have distinct physical characteristics
Male and female sex organs consist of 3 sets of structure
Gonad, internal genitalia, external genitalia
Gonads
Gamete producing organs
Internal genitalia
Accessory glands and ducts
External genitalia
External reproductive structures
Where is sex determined
Programmed in genome
Each nucleated cell of body except gametes contains
23 pairs of chromosomes (46 total: diploid)
22 pairs autosomes: direct development of human body
1 pair sex chromosomes: direct development of internal and external sex organs
What do gametes contain
23 single chromosomes (haploid)
Each egg produced by a female has
An X chromosome
Sperm produced by male has either
And X chromosome or a Y
In females during early embryonic development what happens to one X chromosome
Turns off in each cell
- whether paternal or maternal X is shut off differs in each cel
What x-linked genetic disorders more commonly affect males
Muscular dystrophy, color blindness, hemophilia
(Expressed because they only have one X)
If there’s a Y chromosome
Genetically male
What are 2 ways there can be abnormal sex chromosome distribution
Non disjunction at meiosis 1
- both go into 1 secondary gamete
- one pair of disomic gametes and one pair of nullisomic
Non disjunction at meiosis 2
- one disomic(2 chromatids one gamete) and one nullisomic gamete in a pair
- one pair normal monosomic gametes
XXY
Klinefelters
X
Turner syndrome
Y
Non viable
Stages of egg
Egg-zygote-2 cell stage- 4 cell stage - morula- blastocyst
Embryonic period extends through
The 8th week
What is the time of a standard pregnancy
38 weeks development
40 weeks because standard pregnancy is measured from first day of last mentrual cycle
When is fetus
9 weeks
Wet do reproductive structures begin to differentiate
Seventh week of development
Prior to time of reproductive differentiation considered
Bipotential
Has capacity to become male or female
When bipotential, gonads are
Outer cortex and innner medulla
What are the 2 accessory ducts when bipotential
Wolffian and Müllerian duct
In female gonad cortex
Forms ovary
If female gonad medulla
Regresses
If female wolffian duct
Regressses (testosterone absent)
If female Müllerian duct
Becomes fallopian tube, uterus, cervix, and upper 1/2 vagina (AMH absent)
If male gonad cortex
Regresses
if male Gand medulla
Forms testis
If male wolffian duct
Forms epidiidymis, vas deferents, and seminal vesicle (testosterone present)
If male Müllerian duct
Regresses (AMH present- testis produces)
Male or female development depends on the presence or absence of
Sex determining region of the Y chromosome (SRY gene)
SRY gene
Guides development of internal genitalia into male and inhibit female internal
What does SRY produce
Testis determining factor (TDF)
- SOX9, WT1, SF1
What does TDF do
Guide development of gonadal medulla into testis
What hormones does the testes then produce
Anti-mullerian hormone
Testosterone
Di hydro testosterone
Anti mullerian hormone
Sertoli cells
Causes Müllerian ducts to regress
Testosterone
Leydig cells
Converts wolffian ducts into male acccesory structures
Dihydrotestosterone
Leydig cells
Differentiation of external genitalia
Interstitial cells or Leydig cells secrete
Testosterone
Sertoli cells secrete
Anti-mullerian hormone
At 10 weeks of female growth
Gonadal cortex becomes ovary in absence of SRY protein and influence of female genes
Absence of testosterone causes wolffian duct to degenerate
At birth what happens to females
Absence of AMH allows Müllerian duct to become fallopian tube, uterus, and upper part of vagina
At 10 weeks of male growth
SRY protein directs medulla of bipotential gonad to develop into testis
AMH from testis causes Müllerian ducts to disppear
At birth for males
Testosterone from testis converts wolffian duct into seminal vesicle, vas deferents, epidydimis
DHT controls prostate development