Human Reproduction and Sexual Characteristics

• Chapter Learning Outcomes:
• Explain the development of sex characteristics and the human reproductive system.
• Distinguish between attraction, love, and attachment.
• Explain sexual orientation.
• Identify the causes and consequences of sexually transmitted infections and early pregnancy.
• Reflect on the importance of contraception and reproductive health law.

Sexual Characteristics

• Primary sex characteristics are physical attributes present at birth, such as the vagina, uterus, and ovaries in females.
• Secondary sex characteristics develop during puberty, like breast enlargement, pubic hair, menstruation, and facial hair.
• Sexual dimorphism refers to the physical differences between males and females.
• Primary sex characteristics develop in the womb during the embryonic stage.
• At approximately 5 weeks of pregnancy, gonads (testes and ovaries) form in the embryo.
• Gonads release hormones like testosterone and androgen.
• Testosterone regulates libido, bone mass, fat distribution, muscle mass and strength, red blood cell production, and sperm production.
• Androgen aids in the development of secondary sex characteristics and reproduction.
• Estrogen promotes female reproductive and secondary sex characteristics.
• Progesterone stimulates the growth of female reproductive organs and prepares the uterus for pregnancy.
• Unlike men, female sex hormones are not produced consistently; they follow a cyclical pattern on an approximately 28-day monthly cycle.
• The greatest hormone production occurs during ovulation, when an egg is released from the ovaries.
• Ovulation occurs 14 days after the beginning of the menstrual period.

Female Reproductive System Structures

• Uterine fundus
• Fallopian tube
• Ovary
• Cervical canal
• Cervix
• Vagina
• Ovarian ligament
• Fimbriae
• Uterus
• The clitoris, made of erectile tissue, swells and hardens when a woman is sexually aroused.
• The vagina is a muscular tube that serves as a receptacle for the penis and transports sperm to the uterus.
• The uterus a hollow organ where a fertilized embryo grows into a fetus.
• Two ovaries produce, store, and release egg cells during ovulation.
• Fallopian tubes carry the fertilized egg from the ovary to the uterus.
• Pregnancy begins from fertilization and ends at birth, lasting approximately 260 days.

Male Reproductive System

• The penis is the organ through which males urinate and deliver sperm cells into the vagina.
• Testes or testicles are located in a loose pouch-like sac of skin called the scrotum.
• The vas deferens transports semen, the sperm-fluid.
• The epididymis consists of coiled ducts connected to the vas deferens, where sperm cells are stored.
• The prostate gland and seminal vesicles produce semen to nourish sperm cells.
• Ejaculation is the release of sperm cells from the penis.
• Each ejaculation contains approximately 300 to 500 million sperm cells, which can live up to 48 hours inside the uterus.

Sexual Arousal and Response

• Human sexual arousal is complex and can be produced by direct stimulation of the body's erogenous zones, such as genitals, mouth, breasts, ear, and anus.
• Masturbation is a basic form of sexual stimulation that can lead to pleasure or orgasm.
• Other sexual activities, like intimate kissing, cuddling, necking, petting, or touching erogenous zones, are important to sexual arousal.
• William Masters and Virginia Johnson the biological responses of males and females during sex are quite similar.
• The excitement phase can last from 1 minute to several hours; pulse rate and blood pressure increase, breathing quickens, and the skin shows a rosy flush.
• The plateau phase involves continued changes in the body; in men, the penis becomes more erect and enlarges, while in women, the outer part of the vagina swells, and the clitoris retracts under the clitoral hood and remains highly sensitive.
• Breathing, heart rate, and body temperature increase during the plateau phase.
• The orgasmic phase involves contractions of muscles in and around the penis that stimulate the release of semen containing sperm cells, men usually achieve one orgasm during sexual intercourse.
• In women, orgasm involves contraction of the pelvic muscles that surround the vaginal walls and can happen multiple times.
• The resolution phase involves the body returning to its normal state and reproductive organs returning to their normal state.

Attraction, Love, and Attachment

• Adolescents make new patterns of relationships and commitments with other people as they grow and mature.
• Puberty is an important stage in sexual development, as many boys and girls experience their first sexual attraction.

Gender

• Gender refers to the socially constructed roles, behaviors, expressions, and identities of girls, women, boys, men, and gender-diverse people.
• Rather than being purely assigned by genetics, people often develop gender roles in response to their environment, including family interactions, the media, peers, and education.
• Sex primarily refers to physical attributes, notably sex organs, that distinguish most individuals.
• Gender includes the composite of attitudes and behaviors of men and women (masculinity and femininity).
• Sex is biologically determined by genes and hormones, while gender is learned and perpetuated primarily through family, education, and religion, and it is an acquired identity.
• Sex is relatively fixed/constant through time and across cultures, whereas gender may be variable through time and across cultures because it is socialized.
• Gender identity is the personal conception of oneself as male, female, or rarely, both or neither.
• One's gender identity can be the same as or different from their sex assigned at birth.
• Gender expression is the external appearance of one's gender identity through behavior, clothing, haircut, or voice, and it may or may not conform to socially defined behaviors and characteristics typically associated with being masculine or feminine.
• Transgender is a term used to describe people whose gender identity differs from the sex they were assigned at birth.
• A person are transgender because they feel that the sex they were assigned at birth doesn't match their gender identity, or the gender that they feel they are inside.
• Sexual orientation is an enduring pattern of romantic or sexual attraction to persons of the opposite sex or gender, the same sex or gender, or both sexes or more than one gender.
• People who are attracted to the opposite sex are called "heterosexuals" or "straight".
• People who are attracted to people of the same sex are called "homosexuals", "gay", or "lesbian".
• "Bisexuals" or "bi" people are attracted to both sexes, male or female.

Sexually Transmitted Diseases

• Sexually Transmitted Infections (STIs) are contracted primarily through sexual contact (vaginal, oral, or anal sex).
• Many STIs affect the sex organs themselves, while others have broader and more life-threatening effects.
• Bacterial infections
• Virus.
• HIV/AIDS (Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome) is from contact with body fluids such as through blood transfusion, breastfeeding, and sexual intercourse, it attacks the immune system and eventually kills the infected person.
• Gonorrhea is caused by gonococcal bacteria which attack the lining of the mucous membrane (mouth, throat, vagina, and urethra) and can be treated by penicillin or other antibiotics.
• Syphilis infects the genital areas of the body including the brain and can cause paralysis or death from lack of treatment.
• Chlamydia is from the bacterium chlamydia trachomatis which causes swollen testicles and a burning sensation during urination, it can also cause sterility if left untreated as it damages the uterus, ovaries, and fallopian tubes, in women.

Contraception and Reproductive Health Law

• Contraception are methods that prevent pregnancy.
• Condoms are a common method of contraception that can also prevent some STIs.
• Other common methods available in the Philippines:
• Intrauterine device/IUD which is a tiny device made of flexible plastic that is inserted in the uterus to prevent pregnancy
• Birth control injectables is given every three months to women.
• Oral contraceptive pills is taken everyday.
• Withdrawal method - number of days in each menstrual cycle is recorded and the couple avoids relations during the fertile period
• Calendar method
• The Responsible Parenthood and Reproductive Health Act of 2012/Reproductive Health Law/RH Law guarantees universal access to methods of contraception, fertility control, sexual education, and maternal care.
• The RH Law provides for the "prevention and treatment of HIV/AIDS and other STIs/STDs".
• The RH Law aims to keep couples and women well-informed about available family planning methods that they can freely use depending on their needs and beliefs.
• The RH Law aims to promote awareness among adolescent and youth on sexuality and reproductive health through proper sex education.