Neurobiology of Sex and Sex Differences and Homeostasis

The flashcards cover key topics from the lecture on the neurobiology of sex, sex differences, and the concept of homeostasis in relation to appetite and energy regulation.

What distinguishes humans from other species in terms of sex and gender?

Humans recognize sex and gender as separate concepts, leading to potential internal or externally-imposed conflicts, while other animals primarily recognize sex.

What is the definition of gender in the context of this lecture?

Gender refers to the behaviors and attitudes that a given culture considers to be masculine, feminine, or an alternative.

What is the significance of gonadal hormones in sexual differentiation?

Gonadal hormones like testosterone and estradiol mediate early changes in the developing brain, establishing circuits that promote appropriate reproductive behaviors.

What does the term sexual dimorphism mean?

Sexual dimorphism refers to marked sex differences in appearance and brain structure between males and females.

What are the two sensitive periods described in the Organization/Activational Hypothesis (OAH)?

The organizational phase during gestation when testosterone influences sexual differentiation, and the activational phase during puberty when gonadal hormones activate previously organized brain networks.

How does sexual differentiation of the brain occur during development?

It occurs through the influence of steroids present during sensitive periods which organize brain structures to support sex-specific behaviors.

What organ regulates appetite and is implicated in obesity?

The ventromedial hypothalamus (VMH) regulates satiety, and lesions in this area can lead to obesity.

What role does leptin play in appetite regulation?

Leptin is a hormone produced by fat cells that signals the arcuate nucleus in the hypothalamus to increase appetite when fat levels are low.

What initiates the process of sex determination in humans?

The presence of an X or Y chromosome from the sperm that fertilizes the egg determines whether the fetus develops as male or female.

During which stage does sexual differentiation take place?

Sexual differentiation occurs after sex determination when hormones secreted by gonads direct the development of male or female bodies and behaviors.

What is the role of the sexually dimorphic nucleus of the preoptic area (SDN-POA)?

The SDN-POA is a brain region that is larger in males than in females and is involved in copulatory and ovulatory behaviors.

What does the term 'set point' refer to in the context of homeostasis?

Set point refers to a single value that the body strives to maintain, such as levels of water, glucose, or temperature.

What triggers the release of insulin?

Insulin is released in anticipation of and after a meal to promote glucose uptake into cells.

How do hormones like ghrelin and cholecystokinin relate to appetite control?

These peripheral peptide hormones influence appetite-controlling mechanisms in the hypothalamus, affecting hunger and satiation.

What happens when there is no insulin present in the body?

Without insulin, cells (except the brain) cannot bring glucose into their cells, leading to elevated blood glucose levels.

What is the impact of bilateral lesions in the lateral hypothalamus (LH)?

Lesions in the LH can lead to aphagia, or a lack of eating behavior.

What is the importance of early androgen exposure in sexual orientation?

Early androgen exposure may influence whether an individual identifies as gay or straight, though it only accounts for a minority of cases.

What is a significant finding of Simon LeVay's study regarding the brains of homosexual men?

LeVay's study found that the size of the third interstitial nucleus of the anterior hypothalamus (INAH-3) was larger in heterosexual men than in homosexual men.