Sexual Development and Behavior

What do male testes produce?

Sperm cells.

What do female ovaries produce?

Ova (eggs).

How many chromosomes do sperm and ova each have?

23 chromosomes.

What is formed when a sperm cell fertilizes an ovum?

Zygote.

What develops from a zygote 5 days later?

Blastocyst.

What happens when a blastocyst merges with the uterus?

It leads to the development of an embryo.

After how many weeks is differentiation of cells evident that leads to a fetus?

10 weeks.

What is the total number of chromosomes in a human zygote?

46 chromosomes.

What chromosomes do ova carry?

X chromosomes.

What chromosomes do sperm carry?

X or Y chromosomes.

What genotype represents a female?

XX genotype.

What genotype represents a male?

XY genotype.

What defines a person's genotype?

It is based on genetics.

What defines a person's phenotype?

It is the physical expression of genes.

What determines the development into phenotypic females in humans?

It is unless there is a trigger that shifts genetic expression.

What is the function of the Sex-Determining Region of Y (SRY)?

It produces Testes Determining Factor (TDF).

What occurs in Swyer Syndrome?

Individuals have a 46, XY genotype but appear female.

What is the prevalence of Swyer Syndrome?

Approximately 1 in 80,000.

What do 15-20% of Swyer Syndrome cases involve?

SRY gene mutations or missing segments containing the SRY gene.

What are the physical characteristics of individuals with Swyer Syndrome?

They can have functional female genitals but non-functioning gonads.

What characterizes the 46, XX Testicular Disorder?

Translocation of genetic material leading to male genital development.

What is the estimated prevalence of the 46, XX Testicular Disorder?

Approximately 1 in 25,000.

What happens if the SRY gene is misplaced onto two X chromosomes?

It can result in typically normal development of male genitalia.

What is a primordial gonad?

It can differentiate into male or female gonads.

What develops in the absence of a Y chromosome?

The cortex of the primordial gonad develops into an ovary.

What are the Mullerian and Wolffian ducts?

Both are present in all fetuses, with female ducts developing autonomously.

What is needed for male development?

Hormonal input is required to stop female duct development.

What does dihydrotestosterone stimulate?

Development of external genitalia.

What happens in 5-alpha-reductase Deficiency Syndrome?

Individuals may start puberty transformed into males due to testosterone.

What is the role of aromatase in the presence of testosterone?

It converts testosterone into estradiol.

What does Alpha Fetoprotein do during fetal development?

It binds to estradiol, preventing it from entering the brain.

What is the controversial theory proposed by John Money?

That biology does not matter in terms of sexual development and identity.

What was the outcome for Brenda after raising her as a female?

She later transitioned back to male identity.

How does the Hypothalamic-Pituitary-Gonadal (HPG) Axis function?

It regulates the release of hormones affecting sexual function.

What hormone is labeled as the 'love' hormone?

Oxytocin.

What is the role of Follicle-stimulating hormone (FSH)?

It aids in the development of ova and sperm.

What hormone surge triggers ovulation?

Luteinizing hormone (LH).

What is the main role of estradiol in females?

It is involved in egg maturation and thickening of the uterine wall.

What represents the typical menstrual cycle length?

28 days.

When does the menstruation phase occur in the cycle?

Days 1-5.

What happens during the preovulatory phase of the menstrual cycle?

The development of ovarian follicles and rising estrogen levels.

What is the main function of progesterone in the menstrual cycle?

To prepare the endometrium for a developing zygote.

What happens if fertilization does not occur in the menstrual cycle?

The corpus luteum deteriorates, leading to menstruation.

What is the function of birth control pills?

To interfere with the hormonal signals necessary for ovulation.

What does Plan B do if taken after unprotected sex?

It stops the release of ovum or interferes with the LH surge.

What does Mifepristone do?

It blocks progesterone receptors to end a pregnancy.

What area of the hypothalamus is involved in regulating male sexual behavior?

Medial Preoptic Area.

What is the Lordosis posture in female rodents?

A mating posture involving arching the back and dropping shoulders.

What is the Whitten Effect?

Cycle syncing among females when groups live together.

What triggers the Bruce Effect in female animals?

The introduction of a new male causing miscarriages.

What is the Vandenburgh Effect?

Accelerated sexual maturation of prepubescent females in the presence of a male.

What type of hormones are androgens?

Hormones like testosterone that influence male characteristics.