Reproductive System Notes
Functions of the Reproductive System
1. Has Necessary organs capable of Reproduction
2. Manufactures Hormones
a. Females: Estrogen and Progesterone
b. Males: Testosterone
3. Gamates (Germ Cells) (Specialized Sex Cells): Must be produced by the Gonads of both the male and female before sexual reproduction can occur.
a. Female: Ovaries Produce Egg Cells (Ova)
b. Male: Testes Produce Sperm
4. Meiosis: Sex Cell Division
a. Female: “Oogenesis”
b. Male: “Spermatogenesis”
Chromosomes: There are 46 in all Human Cells. They are paired by size and shape.
Autosomes: Non Sex Celled Chromosomes
Females: XX Chromosomes
Males: XY Chromosomes
Fertilization: “Coitus” Sexual Intercourse
Sperm: *Enter reproductive tract and live for about one to two days although they may remain in tract up to two weeks before degenerating.
*100 million in 1ml of ejaculated fluid
*Less than 20 million per 1ml means that the man is Sterile
*The Number of Sperm cells is high because most die from the acidity in the urethra and vagina or from the high temperatures of the female abdomen. Some lack propulsion ability and die.
Corona Radiata: Outer layer of the Ovum this is the part that must be penetrated in order for fertilization to take place.
The Sperm head produces an enzyme called Hyaluroidosa which acts upon Hyaluronic Acid a chemical that holds together the epithelial cells of the corona radiate.
Conception: This occurs when sperm combines with the egg to form a fertilized egg called a ZYGOTE
Deoxyribonucleic Acid: (DNA) Contains the Genetic Code that is replicated and passed on to each cell as the zygote divides and re-divides to form the embryo.
Cleavage: Zygote repeatedly divides to form and early embryo
· All inherited traits possessed are established at the point of fertilization. The sex of a child is determined by the male
Fetal Development When fertilization occurs the zygote travel down the fallopian tube and is implanted in the endometrial wall of the uterus (9 month process)
· 1st 2 Months after conception the embryo develops without a sexual identity. Male and Female organs develop from the same embryonic cells. Androgen (Male Hormones) are the differentiating factors in the development of the sex
Organs of Reproduction
Female: 2 Ovaries, 2 Fallopian Tubes, The Uterus, The Vagina
Male: 2 Testes, Seminal Ducts, Glands, The Penis
Female Reproductive System
Ovaries: Primary Sex Organs located on either side of the Pelvis. Almost the size of a large almond about (3cm long 1.5 – 3cm wide)
Ovary Formation: Produce Female Ova
Produce Female Hormones (Estrogen and Progesterone)
Graafian follicles: Thousands of microscopic hollow sacs. Ovum slowly develops inside each follicle. This called Maturation. Estrogen is produced here. Every 28 days a single follicle will mature. Occasionally 2 or more follicles may mature releasing more than one ovum.
Menarche: Initial Menstrual Discharge of Blood
Ovulation: Follicles enlarge, it migrates to the outside surface of the ovary and breaks open, releasing the ovum from the ovary. This occurs about 2 weeks before the menstrual period begins. Time depends on emotional and physical health, state of mind, and age. Around 400 eggs will be produced in a lifetime.
Ovum: Consists of cytoplasm and some yolk. Yolk is the initial food source for the growth of the early embryo.
Fertilization of the ovum takes place only in the outer 1/3 of the oviduct (Fallopian Tube Time of fertilization is limited to about 1-2 days following ovulation. The Egg then travels to the uterus and implants itself in the endometrium wall. This occurs under the influence of two hormones of the pituitary gland.
1. Follicle Stimulating Homone (FSH)
2. Luteinizing Hormone (LH)
Corpus Luteum: (Yellow Body) Following ovulation the ruptured follicle enlarges and secretes progesterone, which maintains the growth of the uterine lining. If the egg is not fertilized then the Corpus Luteum degenerates, progesterone production stops, and the thickened glandular endometrium sloughs off.
Fallopian Tubes: (Oviducts) 10cm or 4 inches long and not attached to the ovaries. Portion closest to the ovary is called the Infundibulum. If the fertilized egg implants implants in the fallopian tube this is called an Ectopic Pregnancy. Infundibulum has a number of fringelike folds called Fimbrae. Peristalsis contractions and beating cilia propels the ova down the oviduct in to the uterus.
Uterus: Hollow, thick-walled, pear-shaped, highly muscular organ. It Lies behind the unriary bladder and in front of the rectum. 7.5 cm long, 5cm wide and 2.5cm thick
1. Fundus: Bulging Rounded upper part above the entrance of the
Two oviducts into the uterus
2. Cervix: Cylindrical Lower narrow portion that extends into the
Vagina
3. Body: Middle Portion
Uterine Wall has Three Layers
1. Peritoneum: Outer Serous or Visceral Layer
2. Myometrium: Extremely thick, smooth, muscular middle layer
3. Endometrium: Inner Mucous Layer
Vagina: Short canal that extends from the cervix to the vulva. Consist of smooth muscle with a mucous membrane lining. This allows accommodating the penis during sexual intercourse and for a baby to pass during labor.
Hymen: This is a membrane found at or near the entrance to the vagina. 1st Sexual Intercourse could has some bleeding.
Vulva: External Female Genitalia
Mons pubis: Large Pad of fat covered with course hair and over lies the symphysis pubis
Vestibule: Area surrounding the openings of the urethra and vagina
Clitoris: Above the urethral opening a small structure containing many nerve endings. This provides sexual pleasure when stimulated. This causes vagina to be fully lubricated.
Bartholin’s Glands: Entrance to the vagina which produces mucus
Perineum: Area between the vaginal opening and the rectum. This area may be cut during childbirth known as an Episiotomy.
Breast: Accessory Organs of the female reproduction consist of numerous lobes arranged in circular formations. Clusters of secreting cells surrounding tiny ducts. Single duct extends from each lobe to an opening in the nipple.
Areola: Dark area surrounding the nipple. Changes color during pregnancy to a darker brown.
Prolactin: This is from the anterior lobe of the pituitary gland stimulating the mammary glands to secrete milk following childbirth.
The Menstrual Cycle: The mature Egg develops and is ovulated once every 28 days. Menstruation is when the egg is not fertilized and the endometrium breaks down and then both are discharged out of the female, then the cycle repeats. This cycle starts @ puberty 9 – 17 years old. Generally ages 12 – 15 is when it starts.
1. Follicle Stage
2. Ovulation Stage
3. Corpus Luteum Stage
4. Menstruation Stage
Follicle Stage: (FSH) is secreted by the Pituitary Gland on Day 5 of the Cycle. (FSH) then is circulated to an ovary through the bloodstream. This stimulates follicles one to maturity growing the egg inside. The Follicle fills with Estrogen which stimulates the endometrium. This Stage last about 10 Days
Ovulation Stage: Estrogen concentration in the bloodstream is at its highest, causing the Pituitary Gland to stop (FSH) Secretion. (LH) is secreted by the Pituitary Gland. This happens about day 14 of the cycle. This hormonal combination causes the mature follicle to break. Mature Egg is released called ovulation.
Corpus Luteum or Luteal Stage: (LH) stimulates this to divide quickly. This mass is the Corpus Luteum. Progesterone is now secreted by the Corpus Luteum. It maintains the growth and thickening of the Endometrium. Progesterone is known as the “Pregnancy Hormone” Progesterone also prevents formation of new follicles by inhibiting (FSH). This stage last about 14 Days.
Menstruation Stage: Progesterone Levels will stop (LH) and therefore the Corpus Luteum breaks down. Progesterone decreases so the Endometrium breaks down. This extra linings, eggs, and blood is then released through the vaginal opening. This cycle begins around the 28th day of the cycle. This cycle last about 4 days. Pituitary Gland stimulates (FSH) which starts whole cycle over again.
Menopause: Means “Change in Life” ----- Monthly menstrual cycle comes to an end. Usually occurs around ages 45 – 55. Childbearing is over but their sex drive remains the same. Female experiences during these Anatomical changes.
1. Atrophy of Uterus, Oviducts & Ovaries
2. Atrophy of External Genitalia
3. Vagina becomes cone shaped
4. Atrophy of Vaginal mucous membranes
5. Reduction of Secretion Activities
6. Hot Flashes, Dizziness, Headaches, Joint Pain, Sweating, and Fatigue
7. Abnormal Fears, Depression, Irritability, and the tendency to worry
Male Reproduction System
Testes: Primary Male Reproductive Organs found outside the body in the Scrotum. Each one is about 4cm long, 2.5cm wide, and 2cm thick
Epididymis: Connects the testes with the vas deferens, and helps in final sperm development.
Seminiferous Tubules: Lobes twisted in each testes about 250 in each
Sperm development is stimulated by (FSH) in these tubules. Mature sperm formation takes about 74 days. Function begins around ages 12-14 years of age. Testosterone is the male hormone that is steadily produced. Testosterone stimulates the growth and development of the male reproductive organs and the SEX Dive, also deepens the voice, hair growth, muscle mass, thickens the bones.
The Descent of the Testes: Testes are formed in the abdominal cavity below the kidney when an embryo. During the last 3 months of fetal development the testes migrate to the scrotum.
Spermatic Cord: Ductus deferens, blood & lymphatic vessels, and autonomic nerve fibers. All migrate with the testes.
Cryptochidism: When testes don’t descend and stay up inside then spermatogenesis will be affected.
Vas Deferens: “ductus deferens” These are continuation of the Epididymus.
Storage site for Sperm Cells
1. Excretory duct of the Testes
Seminal Vesicles: Two membranous tubes
1. Produces secretions to nourish and protect the sperm on its journey
Ejaculatory duct: Short – Narrow tube that begin where the vas deferens and the seminal vesicles join. Descend to the Prostate Gland
Penis: External organ along with the scrotum that contains erectile tissue that becomes enlarged (Filled with Blood) during intercourse
Prepuce or Foreskin: Covers the end of the Penis. Foreskin can be removed by an operation called a Circumcision
Prostate Gland: Located in front of the Rectum and Under the Bladder. About the size of a chestnut. It contracts during ejaculation closing off part the Urethra stopping urine from passing.
1. Secretes thin, milky alkaline fluid that enhances sperm mobility
2. Gives semen the strong musky odor.
3. Neutralizes Acid from the Vas Deferens and Vagina
Bulb urethral Glands or Cowpers Glands: Located either side of urethra below Prostrate Gland. Add Alkaline secretion to the semen helping sperm to live longer in the acidic vagina
Urethra: Extends down the length of the penis, opening @ the Urinary Meatus of the Glans.
1. Empty Urine from the Bladder
2. Expel Semen
Impotence: Inability to have or sustain an erection, during intercourse
“Primary”: One who has never had an erection
“Secondary”: One who is currently impotent but has had erections before
Organic Causes are the main reasons but Anxiety and stress can also cause Impotence Treatments may be sexual therapy, penile implants, injection therapy, and oral medication.
Contraception: Means “Against”
1. Abstinence ---- Restraining from Sex
2. Condoms ----- 85% to 95% Effective
3. Pill ----- 95% to 99% Effective
4. Vasectomy ----- In males the vas deferens is cut to stop sperm
5. Tubal Ligation ----- Females Oviducts cut to stop Egg travel
6. IUD ----- Implanted into the Uterus to prevent egg
Implantation 93% to 99%
7. Diaphragm ----- Dome Shaped Rubber Device Inserted in the
Vagina to stop sperm from entering the uterus 90% to 99%
8. Spermicides ----- Foams, Jellies, Cremes, to kill the sperm.
Inserted deep into the vagina
70% - 75%
9. Douching ----- Unknown Effectiveness
10. Withdrawal ----- Penis taken out before ejaculation occurs
70 – 80% Effective
11. Rhythm Method --- 8 Day Period of Menstrual Cycles on days
10 – 17 Abstinence
Contraception Reasons
1. Avoiding Health Risk to Women
2. Spacing Pregnancies: Infant death rate is 50% higher @ 1 year intervals
Compared to 2 or more year spacing
3. Avoiding Birth defects
4. Delay Pregnancy in Marriage (Stress)
5. Limiting Family Size
6. Avoiding Pregnancy all together
7. Curbing population Growth
Infertility: When conception doesn’t occur
1. Damage to Oviducts
2. Low Sperm Count
3. Hormonal Imbalance
4. Other
Infertility Treatments:
1. Clomid or Pergonal promote ovulation more eggs produced each month