Sexual Development and Diversity (Exam 2) Flashcards
what biologically determines sex?
the size of an individual’s gamete size - large gametes (eggs) are female and small gametes (sperm) are male
what are gametes?
sex cells
what are the APA guidelines of sex?
refers to a person’s biological status typically categorized as male, female, or intersex indicated by sex chromosomes, gonads, internal reproductive organs, and external genitalia
what is gender?
a psychosocial term that encompasses the psychological, cultural, and social characteristics we ascribe to men and women (culturally dependent)
what are the APA guidelines of gender?
the attitudes, feelings, and behaviors that a given culture associates with a person’s biological sex
what is gender-normative?
behavior that is compatible with cultural expectations
what is gender non-conforming?
behaviors that are viewed as incompatible with cultural expectations
what is a chromosome?
long tightly packed DNA sequence
true or false: almost every cell in the human body has 21 pairs of chromosomes
false: 23 pairs
which human cells do NOT contain pairs of chromosomes?
egg and sperm cells (only 23 each, not in pairs)
how many chromosomes are inherited from the mother and the father?
one chromosome of each pair from both
how many pairs of chromosomes in humans are identical?
22 pairs
which set pair of chromosomes are the sex chromosomes that differ for males and females?
the 23rd set
what are the identical pairs of chromosomes known as and what do they determine?
autosomes: determine phenotypes such as eye color, height, looks, etc.
true or false: XX is male and XY is female
false (XX is female and XY is male)
one sex chromosome is inherited from the mother via – and is always an –
via ovum and is always an X
one of the sex chromosomes is inherited from the father via – and is –
via sperm and is an X or Y
which sex determines the sex of offspring and why?
males determine because their sperm can carry an X or Y to the females egg which is ALWAYS an X
how many genes do X chromosomes usually have and what do they determine?
about 900 - 1400 genes which determine personality, attributes, etc.
how many genes do Y chromosomes usually have and what do they do?
about 70 - 400 genes with info mostly in male sexual differentiation
which chromosomes (X or Y) are the largest and have the most genetic information?
X chromosomes
at conception, humans consist of one cell which is?
a fertilized egg
what determines whether cells develop into male or female embryo?
the presence or absence of a Y chromosome
which sex-determining gene located on the Y chromosome is the initial switch that causes differentiation in the male direction?
the sex-determining region Y (SRY)
true or false: X-carrying sperm and Y-carrying sperm are produced in roughly the same quantity
true
what is the ratio of male to female fertilized eggs?
160:100
what is the ratio of male to female live births?
105:100
why are there many more male fertilized eggs in comparison to female?
Y chromosomes are smaller and swim faster which can fertilize more eggs while X chromosomes are larger and slower
what is the ratio of male to female teenagers?
100:100
why are there fewer male live births than male fertilized eggs?
males are harder to develop as there are more steps and it is more complex - there are many more ways for it to go wrong
what are the two reasons there are more male miscarriages?
- there are more places for male development to go wrong
- with recessive genetic defects on the X chromosome, a male (XY) having only one X is more likely to express that defect
why are there fewer male teenagers than male live births
they are more likely to die off later in life as they are risk takers
true or false: at 5 weeks male and female internal sex organs are differentiated
false (undifferentiated)
at 5 weeks both XX and XY embryos have what INTERNAL genitalia?(2)
a pair of undifferentiated gonads and two sets of ducts: mullerian and wolffian
at 5 weeks both XX and XY have what EXTERNAL genitalia? (3)
genital tubercle, genital folds, genital swelling
at what week of development do undifferentiated gonads develop into ovaries?
week 7
if the Y chromosome is present at 7 weeks it will express the SRY and result in the production of what?
the testis-determining factor which induces the differentiation of gonads into testes
after the differentiation of gonads into ovaries and testes they begin to produce what which do what?
sex hormones which lead to the development of remaining internal and external genitalia
what sex hormones do testes produce?
androgens (testosterone is one) and a small amount of estrogen and progesterone
what sex hormones do ovaries produce?
estrogen and progesterone and a small amount of testosterone
what other part of the human body produces hormones?
adrenal glands
for female-typical development of internal sex organs which ducts degenerate?
wolffian ducts
for female-typical development which ducts develop into the internal sex organs?
mullerian ducts
what do mullerian ducts develop into for female development? (3)
fallopian tubes, uterus, upper part of vagina
for male-typical development of internal organs which ducts degenerate?
mullerian ducts
for male-typical development which ducts develop into the internal genitalia?
wolffian ducts
what do wolffian ducts develop into in male development? (3)
vas deferens, seminal vesicle, epididymis, ejaculatory ducts
what has to happen in male-typical development for the mullerian ducts to degenerate?
testes must secrete the anti-mullerian hormone (AMH)
in female-typical development what do the external sex organs develop into?
1. genital tubercle –> ?
2. genital folds –> ?
3. genital swelling –> ?
- genital tubercle –> clitoris
- genital folds –> inner labia
- genital swelling –> outer labia
in male-typical development what do the external sex organs develop into?
1. genital tubercle –> ?
2. genital folds –> ?
3. genital swelling –> ?
- genital tubercle –> glans penis
- genital folds –> shaft of the penis
- genital swelling –> scrotum
at around 10 weeks what change occurs to the ovaries and testes?
move down to the upper pelvis
in females the ovaries stay in the upper pelvis until what event and where do they move?
Until birth then they descend in the pelvis and remain on either side of the uterus
at what point in development do the testicles descend into the pelvis?
6-7 months
when do the testicles move down into the scrotum?
shortly before birth
as each testicle enters the scrotum what does it bring with it?
the vas deferens, blood vessels, and nerves
what percent of newborn males have one or both testes undescended?
~ 2%
why is it important for testes to be descended?
they need to be external to be cool enough for sperm production
what does the presence or absence of T during the “critical period” do?
masculinize/demasculinize the brain
what are organizational effects?
hormonal influences during critical periods that cause permanent effects
what are activational effects?
behavioral responses in adulthood from hormones that are reversible
true or false: the development of internal and external sexual organs in the womb is an organizational effect
true
true or false: male puberty (T burst) and female puberty (E burst) and starting menstruation are activational effects
false - they are organizational effects because they are permanent changes
true or false: menstrual changes and mood fluctuations are activational effects
true - they are reversible as they can be blocked with blockers
from childhood to puberty are hormonal influences organizational or activational?
organizational
in adulthood are hormone influences organizational or activational?
activational
what hormone is the main player in sex drive of males and females?
testosterone
true or false: the loss of testes and ovaries after birth has what effect and what can fix that?
decreases sex drive, taking T can help both
in the rat experiment what were the results on the brain of a rat who’s testes were removed before birth?
displayed female-typical behavior even WITH T administered
differentiation causes cells and neural circuits of the — to differentiate between males and females
hypothalamus (H)
at puberty, the female hypothalamus directs what?
a cyclical secretion of sex hormones - menstrual cycle