last updated:

April 9, 2021

[Brain Image]    

PSY 340 Brain and Behavior

Class 23: Sex and Hormones [Outline]



March 17, 2005: The human X chromosome has been fully decoded and the results published in the journal, Nature. The "X" chromosome is comprised of ca. 1.5 million base-pairs  ca. 154 million base-pairs coding for ca. 800 proteins in every cell in the human body (vs. ca. 59 million base-pairs in the "Y" chromosome coding for ca. 70 proteins).

  • two X chromosomes in females and an X and Y chromosome in males.
How are women and men different over and above the obvious physical differences?

Are there real differences between the sexes? If so, why?

[Sexual Differentiation]A. Becoming male or female (that is, sexual differentiation)

Development in males
Development in females

Hormones: Androgens & Estrogens
Hormone Actions
steroid hormones

B. Organizing Effects of Sex Hormones

Organizing Effects -> Causes permanent structural differences to develop gradually in the body.

Activating Effects -> Causes temporary behavior to occur over seconds, minutes, hours, or days following exposure to hormone(s).

   1. Sex Differences in the Hypothalamus

   2. Sex Differences in Childhood Behavior

1. Sexual Behavior in Humans

In males

[menstrual cycle]In females: the menstrual cycle

  Interactive effects of hypothalamus and pituitary gland

Sex Hormones & Nonsexual Characteristics

Male-Femail Brain Connectivity

D. Parental Behavior

Rat Pups[Pups]1. Behavior in Mammals

2. Human Parental Behavior (this is not in text but required)

This page was first posted March 20, 2005.