🫦Intro to Human Sexuality Unit 2 – Sexual Anatomy and Physiology

Basic Anatomy: The Down Low

• Includes external genitalia (vulva, penis, scrotum) and internal reproductive organs (ovaries, uterus, testicles)
• Vulva consists of labia majora, labia minora, clitoris, and vaginal opening
  • Labia majora are outer lips of the vulva, covered in pubic hair after puberty
  • Labia minora are inner lips, rich in nerve endings and vary in size and shape
• Penis made up of shaft, glans (head), and foreskin (if uncircumcised)
  • Shaft contains three cylindrical bodies of spongy tissue that fill with blood during arousal
• Scrotum is a pouch of skin that holds the testicles, regulating their temperature for optimal sperm production
• Ovaries produce eggs (ova) and hormones (estrogen and progesterone)
• Uterus is a muscular organ where a fertilized egg implants and develops into a fetus
• Testicles produce sperm and testosterone, located in the scrotum

Getting Turned On: Sexual Response Cycle

• Consists of four phases: excitement, plateau, orgasm, and resolution
• Excitement phase characterized by increased heart rate, blood pressure, and muscle tension
  • Genital blood flow increases, leading to swelling of the clitoris, labia, and penis
  • Vaginal lubrication begins, and the vaginal walls start to expand
• Plateau phase involves further increases in arousal, with heightened sensitivity of the genitals
• Orgasm is the peak of sexual pleasure, involving rhythmic muscle contractions in the genital region
  • In males, orgasm typically coincides with ejaculation, the expulsion of semen from the penis
• Resolution phase is a gradual return to the unaroused state, with a refractory period for males during which another orgasm is not possible

Hormones: The Body's Sexy Chemical Messengers

• Play a crucial role in sexual development, function, and desire
• Testosterone is the primary male sex hormone, produced mainly in the testicles
  • Responsible for development of male secondary sexual characteristics (deepening of voice, facial hair growth, muscle development)
  • Contributes to libido (sex drive) in both males and females
• Estrogen is the primary female sex hormone, produced mainly in the ovaries
  • Responsible for development of female secondary sexual characteristics (breast growth, widening of hips, distribution of body fat)
  • Regulates the menstrual cycle and prepares the uterus for pregnancy
• Progesterone is another important female sex hormone, produced in the ovaries and placenta during pregnancy
  • Helps prepare the uterine lining for implantation of a fertilized egg
  • Plays a role in breast development and milk production
• Oxytocin is a hormone released during sexual activity, childbirth, and breastfeeding
  • Often called the "love hormone" due to its role in bonding and attachment
  • Stimulates uterine contractions during labor and milk let-down during breastfeeding

Reproduction 101: Making Babies

• Involves the union of an egg (ovum) from the female and a sperm from the male
• Ovulation occurs when a mature egg is released from the ovary, typically once per menstrual cycle
• Fertilization happens when a sperm penetrates the egg, usually in the fallopian tube
  • The fertilized egg (zygote) then travels down the fallopian tube to the uterus
• Implantation occurs when the zygote attaches to the uterine wall, marking the beginning of pregnancy
• Gestation is the period of development from conception to birth, typically lasting about 40 weeks
• Labor and delivery involve the expulsion of the fetus from the uterus through the vagina
  • Contractions of the uterus help push the baby through the birth canal
  • The placenta, which nourished the fetus during pregnancy, is delivered after the baby

Common Sexual Health Issues

• Sexually transmitted infections (STIs) are spread through sexual contact (chlamydia, gonorrhea, herpes, HIV)
  • Can cause symptoms such as genital pain, discharge, or sores, but may also be asymptomatic
  • Prevention methods include using condoms, getting vaccinated (HPV, hepatitis B), and regular STI testing
• Erectile dysfunction (ED) is the inability to achieve or maintain an erection sufficient for sexual intercourse
  • Can be caused by physical factors (cardiovascular disease, diabetes) or psychological factors (stress, anxiety)
• Premature ejaculation is when a man ejaculates sooner than desired, often within 1 minute of penetration
• Vaginismus is the involuntary contraction of the vaginal muscles, making penetration difficult or impossible
• Menstrual disorders such as painful periods (dysmenorrhea) or heavy bleeding (menorrhagia) can impact sexual function
• Infertility is the inability to conceive after 12 months of regular, unprotected intercourse
  • Can be caused by factors affecting either the male or female reproductive system

Pleasure Points: Erogenous Zones

• Areas of the body that are particularly sensitive to sexual stimulation
• Primary erogenous zones are directly related to sexual response and include the genitals (clitoris, penis, vagina, testicles)
• Secondary erogenous zones are not directly related to sexual response but can enhance arousal (nipples, neck, ears, inner thighs)
• The clitoris is a highly sensitive organ, with thousands of nerve endings concentrated in a small area
  • Stimulation of the clitoris is the primary way most women achieve orgasm
• The G-spot is a controversial area said to be located on the front wall of the vagina, about 2-3 inches inside
  • Some women report intense pleasure or orgasm from stimulation of this area
• The prostate gland, located below the bladder in males, can also be a source of sexual pleasure when stimulated
• Erogenous zones vary from person to person, and communication with a partner is key to discovering and enjoying them

Sex Across the Lifespan

• Sexual development begins in utero, with the formation of the genitals
• Puberty marks the onset of sexual maturity, typically occurring between ages 8-13 for girls and 9-14 for boys
  • Characterized by the development of secondary sexual characteristics and the ability to reproduce
• Sexual activity often begins in adolescence or early adulthood, with exploration of one's sexuality and sexual relationships
• Sexual function and desire can change throughout adulthood due to factors such as hormonal changes, health issues, and life stressors
• Menopause in women, typically occurring in the late 40s to early 50s, can lead to changes in sexual function (vaginal dryness, decreased libido)
• Erectile dysfunction becomes more common in men as they age, often due to underlying health conditions
• Sexual activity and intimacy remain important aspects of well-being throughout the lifespan, including in older adulthood
  • Adaptations may be necessary due to physical changes, but sexual pleasure and fulfillment are still possible

Cultural and Social Perspectives on Sexual Anatomy

• Views on sexual anatomy and function vary widely across cultures and societies
• Some cultures place great importance on female virginity, leading to practices such as female genital mutilation (FGM)
  • FGM involves the partial or total removal of external female genitalia for non-medical reasons
  • Can cause severe complications and lifelong health issues
• Circumcision, the removal of the foreskin of the penis, is practiced in some cultures for religious or cultural reasons
  • Debate exists over the medical benefits and ethical considerations of routine infant circumcision
• Gender identity and sexual orientation can influence how individuals relate to and feel about their sexual anatomy
• Transgender individuals may experience gender dysphoria, a disconnect between their anatomy and gender identity
  • Gender confirmation surgery can help align one's physical characteristics with their gender identity
• Societal norms and expectations around sexual behavior and expression can impact how people view and engage with their own sexual anatomy
  • Sex education and open communication are important for promoting healthy and informed attitudes toward sexual anatomy and function