BIO 336 - 3.1

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Questions and Answers

What is one of the organizing effects of sex hormones during puberty?

Breast development in females (correct)

Facial hair growth in females

Increase in sex drive

Menstrual cycle initiation

What is a key influence on childhood toy preferences according to the content?

Cultural norms only

Socialization and prenatal testosterone (correct)

Cognitive development stages

Genetic factors only

Which of the following best describes the activating effects of sex hormones?

They occur at any time and can modify behavior temporarily. (correct)

They have no effect on emotional states.

They take effect only during childhood.

They permanently alter brain structure.

Which area of the brain is mentioned as having a sexually dimorphic nucleus in males?

Anterior hypothalamus Signup and view all the answers

What role does oxytocin play in reproductive behavior?

It is crucial for uterine contractions during delivery. Signup and view all the answers

What behavior is associated with the bidirectional link to testosterone?

Aggression Signup and view all the answers

How does testosterone influence sexual arousal in males?

It binds to the hypothalamus and triggers dopamine release. Signup and view all the answers

Which difference is considered the largest in behavior between sexes after puberty?

Sexual preference Signup and view all the answers

What effect do high testosterone levels have on males in relationships?

They increase the desire to seek multiple sexual partners. Signup and view all the answers

How can prenatal testosterone levels affect girls' behavior later in life?

Development of male toy preferences Signup and view all the answers

What effect do sex hormones have on mood and cognition during pregnancy?

Produce temporary effects on emotional arousal and cognition Signup and view all the answers

Which hormone is primarily responsible for inhibiting sexual arousal?

Serotonin Signup and view all the answers

Which of the following substances is known to inhibit testosterone production?

Phthalates Signup and view all the answers

What link has been found regarding oxytocin and human behavior?

It is associated with higher levels of trust and generosity. Signup and view all the answers

How does being married generally affect testosterone levels in males?

They are generally lower than those of single males. Signup and view all the answers

What is the function of oxytocin during the process of breastfeeding?

Stimulates mammary glands to release breast milk. Signup and view all the answers

What is the role of follicle-stimulating hormone (FSH) during the menstrual cycle?

To promote the growth of the ovarian follicle Signup and view all the answers

During which period of the menstrual cycle is fertility at its peak?

The periovulatory period Signup and view all the answers

How does the release of progesterone affect the menstrual cycle?

It prepares the uterus for implantation Signup and view all the answers

Which factors influence a woman's sexual responsiveness during the periovulatory period?

Increased estradiol levels Signup and view all the answers

What hormonal change occurs in females after the birth of young, influencing maternal behavior?

Increased secretion of oxytocin and prolactin Signup and view all the answers

What characteristic behavior change occurs in women during the periovulatory period?

Increased interest in flirting Signup and view all the answers

What effect do birth-control pills have on female hormones?

They prevent the surge of FSH and LH Signup and view all the answers

What behavior changes typically occur in females as a result of hormonal influences during the menstrual cycle?

Increased aggression and higher appetite after menstruation Signup and view all the answers

Study Notes

The Menstrual Cycle

The hypothalamus and pituitary gland work together with the ovaries to regulate the menstrual cycle.
Follicle-stimulating hormone (FSH) stimulates the growth of a follicle in the ovary, which contains an immature egg.
The follicle produces estrogen (estradiol), which increases as the cycle progresses.
Increased estradiol triggers the release of both FSH and luteinizing hormone (LH), leading to ovulation.
Birth control pills prevent the surge of FSH and LH, preventing ovulation.
Progesterone, released from the remnants of the follicle, prepares the uterus for implantation and inhibits further LH release.

The Periovulatory Period

This period, around the middle of the menstrual cycle, marks the time of highest fertility.
Women experience increased sexual responsiveness during this period, including heightened interest in erotic content and flirting, as well as attraction to more masculine men.

Parental Behavior

Oxytocin and prolactin, released after childbirth, promote milk production and maternal behavior.
Oxytocin, a hormone released by the pituitary gland, plays a role in various aspects of reproduction and social behavior.
Oxytocin stimulates uterine contractions during childbirth and milk release, is released during orgasm, and is involved in establishing social bonds, promoting generosity, trust, and reducing anxiety.

Sexual Arousal in Males

Testosterone is crucial for male sexual arousal and triggers the release of dopamine in the hypothalamus, stimulating erection.
Dopamine promotes sexual activity, while serotonin inhibits it by blocking dopamine release.
Antidepressants, which increase serotonin levels, can decrease sexual arousal as a result.

Testosterone Levels & Behavior

Testosterone levels correlate with sexual arousal and the desire for multiple sexual partners.
Married or committed men generally have lower testosterone levels than single men.
High testosterone levels can drive the desire for additional sexual partners, even within committed relationships.
Women also experience higher testosterone levels when single compared to married women.
Phthalates, a group of chemicals found in cosmetics and other products, can inhibit testosterone production.

Genes & Sex Differences

Sex differences are not solely explained by hormones.
Genes on the X and Y chromosomes also contribute to biological differences between males and females.

Organizing and Activating Effects of Sex Hormones

Organizing Effects: occur during sensitive periods of development, influencing the development of sex organs (prenatally) and secondary sexual characteristics (puberty).
Activating Effects: can occur at any time in life and temporarily activate specific responses, such as increased sex drive or menstruation.
Current hormone levels influence the strength of activating effects.

Sex Differences in the Hypothalamus

Early sex hormone exposure influences the development of the hypothalamus, amygdala, and other brain regions.
The sexually dimorphic nucleus, located in the anterior hypothalamus, is larger in males and is involved in controlling male sexual behavior.
The female hypothalamus exhibits a cyclical pattern of hormone release, regulating the menstrual cycle.

Sex Differences in Childhood Behavior: Toy Preferences

The second largest observed sex difference in behavior is toy preference (after sexual preference).
Boys typically exhibit preferences for cars, trains, and balls, engaging in rough play, while girls prefer dolls, tea sets, and cooperative play.
This difference is partly due to socialization but also reflects inherent preferences observed even in monkeys raised without human influence.
Prenatal testosterone exposure influences toy preferences, as girls exposed to higher levels often display more male-typical preferences.

Activating Effects of Sex Hormones on Behavior

Sex hormones can temporarily modify behavior through activating effects, influencing sexual behavior within minutes.
A bidirectional relationship exists between behavior and hormone secretion, as seen with aggression and testosterone.