Reproductive System: Male Anatomy

• The reproductive system produces, stores, and transports gametes for reproduction.
• It also produces hormones that influence sexual development and reproductive functions.

Male Reproductive System

• Designed to produce and deliver sperm to the female reproductive system.
• Consists of internal and external organs.

Male External Organs

• Penis: Used for sexual intercourse and the passage of urine and semen.
• Scrotum: A sac that holds and regulates the temperature of the testes.

Male Internal Organs

• Testes: Produce sperm and testosterone.
• Epididymis: Stores and matures sperm.
• Vas Deferens: Transports sperm from the epididymis to the urethra.
• Seminal Vesicles: Produce a nutrient-rich fluid that nourishes sperm.
• Prostate Gland: Secretes a fluid that protects and enhances sperm motility.
• Bulbourethral (Cowper's) Gland: Produces a lubricating fluid before ejaculation.
• Urethra: A tube that carries urine and semen out of the body.

Female Reproductive System

• Designed to produce eggs, support fertilization, and sustain pregnancy.
• Consists of internal and external organs.

Female External Organs (Vulva)

• Labia Majora & Labia Minora: Protect the internal reproductive organs.
• Clitoris: Contains nerve endings and is involved in sexual stimulation.
• Vaginal Opening: Entryway to the vagina.

Female Internal Organs

• Ovaries: Produce eggs (ova) and hormones like estrogen and progesterone.
• Fallopian Tubes: Transport eggs from the ovaries, which is the site of fertilization.
• Uterus (Womb): Houses and nourishes a developing fetus.
• Cervix: The lower part of the uterus that connects to the vagina.
• Vagina: Receives sperm, serves as a birth canal, and is an exit for menstrual flow.

Physiological Processes of the Male Reproductive System

• Spermatogenesis: Sperm production in the testes.
• Erection & Ejaculation: The release of sperm-containing semen during sexual activity.
• Hormonal Regulation: Testosterone regulates sperm production and male characteristics.

Physiological Processes of the Female Reproductive System

• Oogenesis: The production and maturation of eggs in the ovaries.

Menstrual Cycle: Menstrual Phase (Days 1-5)

• Shedding of the uterine lining beginning the menstrual cycle.
• Hormonal fluctuations can cause mood swings, irritability, or sadness.
• Body iron levels may decrease slightly due to blood loss, sometimes causing dizziness or weakness.

Menstrual Cycle: Follicular Phase (Days 1-13)

• Egg development and estrogen production.
• Follicular growth prepares the body for ovulation
• Thickening of the uterine lining occurs.
• Rising estrogen levels increase energy and improve mood.

Menstrual Cycle: Ovulation (Day 14)

• A mature egg is released from the ovary making a woman most fertile
• Women may experience mild cramping or increased libido.
• Changes in cervical mucus facilitate sperm movement.
• A surge in luteinizing hormone (LH) triggers egg release.

Menstrual Cycle: Luteal Phase (Days 15-28)

• Progesterone maintains the uterus for pregnancy.
• Women may experience symptoms of premenstrual syndrome (PMS).
• Hormonal changes prepare the uterus for a potential pregnancy or shedding of the uterine lining.

Fertilization and Pregnancy

• Fertilization occurs in the fallopian tube if sperm meets an egg, leading to pregnancy.

Journey of a Sperm Cell: Production in the Testes

• Sperm cells are produced in the seminiferous tubules of the testes.
• Spermatogenesis takes 64-72 days and involves stages from spermatogonia to spermatozoa.
• Sertoli cells nourish and support developing sperm.

Journey of a Sperm Cell: Maturation in the Epididymis

• Sperm travel to the epididymis, located behind the testes.
• Sperm gain motility and the ability to fertilize an egg over about 14 days.
• Sperm are stored in the tail of the epididymis until ejaculation.

Journey of a Sperm Cell: Transportation via the Vas Deferens

• Sperm are transported from the epididymis through the vas deferens during ejaculation.
• Seminal vesicles and the prostate gland contribute fluids to nourish sperm and form semen.

Journey of a Sperm Cell: Ejaculation and Entry into the Female Reproductive Tract

• Sperm are released into the vagina when a male ejaculates, traveling at about 28 mph (45 km/h).
• A single ejaculation contains 200-600 million sperm; however, only a few hundred reach the egg.
• Alkaline seminal fluid helps sperm survive the acidic environment of the vagina.

Journey of a Sperm Cell: Passage Through the Cervix and Uterus

• Sperm that survive enter the cervix
• Cervical mucus becomes thin and slippery to help sperm swim through.
• Sperm use flagella and muscle contractions of the uterus to move forward.

Journey of a Sperm Cell: Journey Through the Fallopian Tubes

• Sperm swim toward the fallopian tubes, where fertilization occurs.
• Only a few hundred sperm reach the fallopian tubes.
• Sperm undergo capacitation to become hyperactive and more able to penetrate the egg.

Journey of a Sperm Cell: Penetration of the Egg and Fertilization

• Sperm must break through the corona radiata (outer layer of cells) and the zona pellucida (protective shell).
• The acrosome, on the sperm's head, releases enzymes to break down the zona pellucida.
• The egg's membrane blocks entry to other sperm once a sperm successfully enters (cortical reaction).
• The sperm's nucleus fuses with the egg's nucleus, forming a zygote with 46 chromosomes.

Journey of a Sperm Cell: Implantation and Pregnancy

• The fertilized egg undergoes cell division, travels to the uterus, and implants into the uterine lining.
• This marks the beginning of pregnancy.

Key Facts About Sperm

• Sperm can survive 3-5 days inside the female reproductive tract.
• Sperm travel at about 5 mm per minute and reach the egg in 30 minutes to a few hours.
• Only one sperm fertilizes the egg.