Lesson 3: What Constitutes Sex? - Human Reproduction PDF

W H AT CONSTITUTES SEX? Lesson 3 L E SS O N 1 : A N AT O M Y A N D PHYSIOLOGY OF REPRODUCTION Objectives Differentiate the female and the male reproductive systems, and Understand the basis for the physiological processes in female and male INTRODUCTION Humans experience various phy...

W H AT CONSTITUTES SEX? Lesson 3 L E SS O N 1 : A N AT O M Y A N D PHYSIOLOGY OF REPRODUCTION Objectives Differentiate the female and the male reproductive systems, and Understand the basis for the physiological processes in female and male INTRODUCTION Humans experience various physical and emotional changes from childhood to adulthood. These changes are gradual and progress at different ages and speed in different people. These stages are based on human growth and development from childhood, adolescence, adulthood, and old age. This chapter focuses on the adolescent stage of human development, which is characterized by dynamic changes in physical and behavioral traits. Despite differences in physical appearance, the sexual organs of men and women arise from the same structures and fulfill similar functions. Each person has a pair of gonads: ovaries are female gonads; testes are the male gonads. The gonads produce germ cells and sex hormones. The female germ cells re ova (egg) and the male germ cells are sperm. Ova and sperm are the basic units of reproduction; their union can lead to the creation of a new life. THE BIOLOGICAL FEMALE Anatomy is the study of body structure in relation to body parts. The female sexual anatomy is designed for the production and fertilization of ovum, as well as carrying and delivering infant offspring. Puberty signals the final development of primary and accessory organs that support reproduction. A. The female external genitalia consists of the following:  Vulva – all the external genital structures taken together;  Mons veneris – pads of fatty tissue between pubic bone and skin;  Labia majora – outer lips surrounding all the other structures;  Prepuce – clitoral hood (foreskin above and covering clitoris);  Clitoris – glans (head), shaft, and crura (root), the clitoris is particularly sensitive to stimulation;  Labia minora – inner lips surrounding the vestibule where sweat and oil glands, extensive blood vessels, and nerve endings are located;  Vestibule – area surrounding the urethral opening and vagina, which is highly sensitive blood vessels and nerve endings;  Urethral opening – end of tube connecting to bladder and used for urination;  Vaginal opening – also called introitus; and  Perineum – area of skin separating the genitalia from the anus; distance is less in females than males. THE FEMALE INTERNAL REPRODUCTIVE STRUCTURES CONSIST OF THE FOLLOWING AS DESCRIBED AND SHOWN BELOW:  Vagina – collapsible canal extending from vaginal opening back and upward into body to cervix and uterus. During arousal, it is engorged with blood. This aids its expansion and triggers the release of lubricants from vaginal mucosa;  Cervix – small end of uterus to which vagina leads. It is the opening in cervix leading to interior of uterus;  Uterus – womb, organ within pelvic zone where fetus is carried;  Fallopian tubes – carry egg cells from ovaries to uterus, this is where fertilization occurs; and  Ovaries – produce estrogen and progesterone. Estrogen influences female sex characteristics and initiates menstrual cycle. Progesterone aids in regulation of menstrual cycle and promotes mature development of uterine lining to allow for zygote implantation. Also produce ova, egg cells, and bring them to maturity. As many as 1 million immature ova are present at birth, with about 400,000 surviving to puberty. Of these, only about 400-450 are typically brought to maturity and released into the fallopian tubes. PUBERTY The menstrual cycle marks the beginning of puberty in females. The first episode occurs between 11 – 15 years of age referred to as menarche. Menstruation pertains to the sloughing off of uterine lining if conception has not occurred. It may last within two to six days which follows a cycle ranging from 24 – 42 days. Regardless of the length of the cycle, menstruation begins about 14 days after ovulation (plus or minus one to two days). The overall cycle is governed by the hypothalamus as it monitors hormone levels in the bloodstream. 3 PHASES OF MENSTRUAL CYCLE  Menstrual phase. This occurs if the ovum is not fertilized and does not implant itself into the uterine lining. The continued high levels of estrogen and progesterone causes the pituitary to stop releasing follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Estrogen and progesterone levels decrease causing the endometrium to be sloughed off, and bleeding ensues. It is during this time that ovarian hormones are at their lowest levels. Proliferative phase. It occurs when the hypothalamus stimulates the pituitary gland to release FSH that stimulates the ovaries to produce estrogen and causes ova to mature in the ovarian follicles. Endometrium is repaired, thickens, and becomes well-vascularized in response to increasing levels of estrogens. Secretory phase. It occurs when the pituitary gland releases LH that causes the ovary to release a mature ovum and causes the remaining portion of the follicle to develop into the corpus luteum. The corpus luteum then, produces progesterone. Endometrial glands begin to secrete nutrients, and lining becomes more vascular in response to increasing level of progesterone. F E M A L E S E C O N D A RY S E X UA L CHARACTERISTICS 1. Widening of hips and pelvis – accommodates giving birth, but also results in downward shift in center of gravity. 2. Enlargement of breasts – at puberty, both the glandular and fatty tissues of the breasts develop considerably. Differences in breast size between women are primarily due to differences in the amount of fatty tissue. It is also not uncommon for one of a woman’s breasts to be slightly larger than the other. The glandular tissue of the breasts responds to sex hormones, and the breasts are involved in a women’s sexual arousal. The glandular tissue produces milk toward the end of pregnancy and after childbirth in response to hormone levels. MORE FEMALE CHARACTERISTICS  Generally shorter than men;  Greater proportion od body weight composed of fat than men;  Two X chromosomes reduces expression of many sex-linked conditions; and  Lower mortality rate at every age and longer projected life span than men. THE BIOLOGICAL MALE The male sexual anatomy is designed for the production and delivery of sperm for fertilization of the female’s ovum. Puberty signals the final development of primary and accessory organs that support reproduction.  T H E M A L E E X T E R N A L G E N I TA L I A  Prepuce – foreskin covering head of penis, removed in male circumcision;  Penis – glans (head), shaft and root. The glans is particularly sensitive to stimulation. Running the length of the penis is the urethra surrounded by the spongy body and two cylindrical chambers know as the cavernous bodies/ During arousal, these become engorged with blood, resulting in erection;  Corona – rim of glans where it arises from shaft;  Frenulum – thin strip of skin connecting glans and shaft on underside of penis;  Scrotum – sac that encloses the two compartments housing the testes;  Urethral opening – found on head of penis this is the end of tube connected to bladder and used for urination. It is also tube to which internal structures deliver semen by which male ejaculates; and  Perineum – area of skin separating the genitalia from the anus, distance is greater in males than females.  THE MALE REPRODUCTIVE ORGANS  Testes – produce androgen, particularly large quantities of testosterone, which greatly influence male development and drive sexual motivation; also produce sperm cells in virtually unlimited quantity over the entire course of the lifespan;  Vas deferens – travels from testicle toward urethra carrying sperm;  Seminal vesicles – two glands that produce alkaline fluid rich in fructose sugar, comprising some 70% of semen volume. Alkaline nature may stimulate sperm to start self-propulsion and sugar may provide sperm nutrients. Ducts carry fluid and connect with vas deferens forming ejaculatory ducts;  Ejaculatory ducts – connect vas deferens to urethra;  Prostate – gland producing alkaline secretions that account for about 30% of semen volume. Alkaline nature may help counteract otherwise, acidic environment of urethra and vagina making them more hospitable for sperm. Fluid passes through a series of ducts along the wall off urethra; and  Urethra – tube within penis that carries sperm and semen the rest of the way to the opening of the penis. THE MALE INTERNAL REPRODUCTIVE ORGANS THE MALE INTERNAL REPRODUCTIVE ORGANS  Testes – produce androgen, particularly large quantities of testosterone, which greatly influence male development and drive sexual motivation; also produce sperm cells in virtually unlimited quantity over the entire course of the lifespan;  Vas deferens – travels from testicle toward urethra carrying sperm;  Seminal vesicles – two glands that produce alkaline fluid rich in fructose sugar, comprising some 70% of semen volume. Alkaline nature may stimulate sperm to start self-propulsion and sugar may provide sperm nutrients. Ducts carry fluid and connect with vas deferens forming ejaculatory ducts;  Ejaculatory ducts – connect vas deferens to urethra;  Prostate – gland producing alkaline secretions that account for about 30% of semen volume. Alkaline nature may help counteract otherwise, acidic environment of urethra and vagina making them more hospitable for sperm. Fluid passes through a series of ducts along the wall off urethra; and  Urethra – tube within penis that carries sperm and semen the rest of the way to the opening of the penis. MORE MALE CHARACTERISTICS  Generally taller and greater proportion of body weight composed of water;  Proportionately larger heart and lungs, presumably to handle greater fluid volume;  Exposure to greater levels of testosterone resulting in heavier body and facial hair, but also increased frequency and degree of baldness; and  Single X chromosome resulting in sex-linked conditions such as colorblindness and hemophilia. MALE HORMONES The testosterone is the major male hormone produced mainly by the testes, but there are other glands called the adrenal glands that also produce some testosterone. In case a man has lost his testes, these glands would continue to produce testosterone to support the male physical appearance. Testosterone is responsible for the growth and development of a boy during adolescence and for the development of sperm and secondary sexual characteristics. M A L E S E C O N D A RY S E X UA L CHARACTERISTICS  No monthly cycle;  Elongation of vocal cords (lower voice);  Broader shoulders; and  Deeper chest cavity. LESSON 2: THE PROCESS OF REPRODUCTION Lesson Objectives 1. Define fertilization, conception and pregnancy; 2. Explain how pregnancy occurs and its prevention; and 3. Identify the complications of early pregnancy in the growing adolescent. INTRODUCTION Although human beings are fully sexually differentiated at birth, the differences between males and females are accentuated at puberty. This is when the reproductive system matures, secondary sexual characteristics develop, and the bodies of males and females appear more distinctive. Female puberty usually begins at about 8-13 years of age; the reproduction maturation of boys lags about two years behind that of girls. The physical changes of female puberty include breast development, rounding of the hips and buttocks, growth of the hair in the pubic region and the underarm, and the start of menstruation. H O W D O E S O N E O V U L AT E ? The major landmark of puberty among females is the onset of the menstrual cycle, the monthly ovulation cycle that leads to menstruation (loss of blood and tissues lining the uterus) in the absence of pregnancy. The menstrual cycle is from the first day of a period until the day before the next period starts. Normally, it lasts around 28 days, on the average, but can be as short as 21 or as long as 40. Whatever the length, ovulation will happen about 10-16 days before the start of the next period. HOW DOES PREGNANCY OCCUR?  HOW DOES PREGNANCY OCCUR? For pregnancy to proceed, the sperm needs to meet up with an egg. Pregnancy officially starts when a fertilized egg implants in the lining of the uterus. Pregnancy happens 2-3 weeks after sexual intercourse. This is redundant so it was it redacted. Conception is the process that begins with fertilization of an egg by the sperm and ends with implantation. When a male and female have a sexual intercourse, the penis fits into the woman’s vagina. Ejaculation or coming releases the sperm via the penis into the vagina. The sperm swims through the female’s cervix, into the womb, and finally into the fallopian tubes. Once the egg or ovum has been released into the fallopian tube, hundreds of sperm swim up to reach it. Finally, the sperm penetrates the egg in the fallopian tube where fertilization takes place and eventually, becomes an embryo. Once the embryo (fertilized egg) attaches to the inner lining of the uterus (endothelium), a fetus develops within five to seven days from a ball of cells floating in the uterus, which officially begins pregnancy. HOW DOES PREGNANCY OCCUR? A normal pregnancy lasts 37-42 weeks (nine months). That is measured from the first day of the last period. Pregnancy is discussed in terms of trimesters (three-month periods), since each trimester is very different from the rest. After eight weeks, the embryo is officially referred to as a fetus. W H AT C A N B E D O N E T O P R E V E N T TEENAGE PREGNANCY? Teen pregnancy has a tremendous impact on the educational, social, and economic lives of young people. Early parenting reduces the likelihood that a young woman will complete high school and pursue the necessary post- secondary education needed to compete in today’s economy. Although there is a decline in teenage pregnancy rates it has been steady over the past two decades. Teens are still engaging in sexual activity and teen girls are still getting pregnant. Equipping the youth with the knowledge, skills and attitudes necessary to protect themselves against unwanted pregnancy and provide them access to reproductive healthcare are needed.  CHART FOR CONTRACEPTION Male Condom: Rolled over 80-85 percent Low cost, Do not use with oil- Can be rubber sheath the penis easily based lubricants effective that fits over the accessible, such as creams and in penis and reduces lotions preventi risk of on of STDs/STIs STIs and HIV/AIDS Implantable Continuous Not known Continuous Implant of the capsule None Hormone Device: release of birth control in the upper arm; continuous hormones for five years done by the doctor release of hormone Calendar Allows the Theoretically 85 No cost and Woman must keep None method: woman woman to percent but in under the track with the help of predicts the day keep track of reality about 60 control of the a calendar of ovulation by “safe” days percent woman keeping a for sex calendar of the length or each menstrual cycle Sterilization: Passageway Theoretically 100 Highly Doctor performs an None vasectomy for for the sperm percent, but effective, operation  Type of How it Effectiveness Benefits Instruction for Use Benefits Contraceptive Works Other Method than Contrace ption Birth Control Pill: Alters natural Theoretically 99- Low cost, easily Taken daily after None contains ovulation 100 percent, but available, and menstrual cycle begins synthetic cycle women have controlled by the estrogen conceived on the woman ”pill” Birth Control Not known Given by the doctor None Injection: given in the first days of the menstruation and then every 2- 3 months Withdrawal: Prevents the Theoretically, 85 No cost under Dependent on the man None removal of the semen from percent but in the control of the penis from the going into the reality, about 70 man and the vagina before vagina percent woman involved ejaculation Intrauterine Inserted Theoretically 95- Long-lasting and Inserted by the doctor None Device (IUD) inside the 98 percent relatively in the first few days of uterus by a inexpensive menstruation; should be doctor examined every few W H A T A R E T H E H E A LT H E F F E C T S O F E A R LY P R E G N A N C Y I N T H E G R O W I N G ADOLESCENT? There are serious health risks associated with early pregnancy because a young woman’s body is not mature enough to handle bearing a child. When a woman is under 20, the pelvic area (the bone surrounding the birth canal) is still growing and may not be large enough to allow the baby to easily pass through the birth canal. This can result in what is called an “obstructed labor”. Obstructed labor is dangerous to both mother and child and requires the help of trained medical professionals. Under the best circumstances, the young woman will have an operation called a “caesarean section” in which a cut is made in the abdomen and the baby is removed directly from the uterus. W H A T A R E T H E H E A LT H E F F E C T S O F E A R LY P R E G N A N C Y I N T H E G R O W I N G ADOLESCENT? A major contributor to high maternal mortality rates is adolescent pregnancy. If a young woman is not physically mature, the uterus may tear during the birth process, and she may die because of blood loss. If she is lucky and survives the delivery, she might face fistula due to prolonged labor. A baby’s head can also tear the vagina causing a hole between the vagina and the bladder or between the vagina and the rectum, resulting in what is known as a fistula. Unless she has an operation to fix her problem, for the rest of her life, she will not be able to hold her urine or feces and this will make her a social outcast.  In addition, younger women who become pregnant face a higher risk than older women in developing a number of other complications. These complications can be any or a combination of the following manifestations:  Excessive vomiting;  Severe anermia;  Hypertension;  Convulsions;  Difficulty in breast feeding (if the girl is too young to produce milk);  Premature and low birth weight babies;  Infection;  Prolonged labor; and  High maternal mortality or death. W H A T A R E T H E H E A LT H E F F E C T S O F E A R LY P R E G N A N C Y I N T H E G R O W I N G ADOLESCENT? The risk of having serios complications during pregnancy or childbirth is much higher for girls in their early teens than for older women. Ages of 20- 30 years are the safest period of women’s life for child bearing. The major difference between girls in their early teens and older women is that girls aged 12-16 years are still growing. The pelvis, or the bony birth canal, of a girl can grow wider by as much as 20% between the time she begins menstruating and the time she is 16 years old. This widening of the pelvis can make the crucial difference between a safe delivery and obstructed labor. ACTIVITY NO. 2  Reflection Paper no. 1:  Comment on the article: “Sex Myths: It’s The Man’s Responsibility to buy condoms.”  See: https://www.verywellhealth.com/ sex-myths- mans- responsibility-to-buy- condoms-3132649