Discovering Human Sexuality 4e Chapter 3 Outline

The Male External Genitalia Are the Penis and Scrotum

The penis combines erotic, reproductive, and urinary functions

Box 3.1 Male Circumcision

Some disorders affect penile function

Box 3.2 How Big Should a Penis Be?

Box 3.3 Diphallia

Penile Erection Involves Nerves, Blood, and Chemistry

Erection is the filling of the penis with blood

Muscles are also involved in erection

Erections occur during sleep

The scrotum regulates the temperature of the testicles

The Testicles Produce Sperm and Sex Hormones

Other glands contribute secretions to the semen

Box 3.4 Declining Sperm Counts

Cancer and other disorders can affect the testicles

Other glands contribute secretions to the semen

What is semen?

Ejaculation Requires Coordination of Muscles and Glands

The testicles secrete sex hormones

Box 3.5 The Secret Life of Semen

The brain and pituitary gland regulate hormone levels

Box 3.6 Steroids and Sports

Nudity Is Culturally Regulated