Male Reproductive System • It includes both internal and external organs • Two main functions: • Production and storage of sperm – • The male reproductive cells • And the transfer of sperm to the female’s body during sexual intercourse.
Male Reproductive System • Early teen years (12-15 years old), the male reproductive reaches maturity. • Testosterone – • The male sex hormone • Produced in the pituitary gland
Testosterone • Initiates physical changes that signal maturity: • Broadening of the shoulders • Development of muscles • Facial and body hair • Deepening of the voice • Controls the production of sperm
External Male Reproductive Organs • Testes (singular, testis) • Scrotum • Penis
Testis • Divided into tiny tubules in which sperm are formed • Part of both the reproductive and endocrine system • Produce male sex hormones (testosterone) • Temperature regulation – Ideal right below body temperature • Cremasteric muscle and reflex • When this muscle contracts, the spermatic cord is shortened and the testicle is moved closer up toward the body, which provides slightly more warmth to maintain optimal testicular temperature. • When cooling is required, the cremasteric muscle relaxes and the testicle is lowered away from the warm body and is able to cool. • Located in the scrotum
Scrotum • Skin and muscle containing the testicles • It is an extension of the abdomen • An external skin sac
Penis • Tube-shaped organ that extends from the trunk of the body just above the testes. • Composed of spongy tissue that contains many blood vessels. • When blood flow to the penis increases, it becomes enlarged and erect. • Also called an erection
Semen • Released by the penis • It is a thick fluid containing sperm and other secretions from the male reproductive system.
Internal Male Reproductive Organs • Vas deferens • Urethra • Seminal vesicles • Prostate gland • Cowper’s gland
Vas Deferens • Tubes that extend from each epididymis to the urethra • During ejaculation smooth muscle walls contract • Propel sperm to urethra
Urethra • Passageway which both semen and urine leave the male body
Seminal Vesicle • Provides nourishing fluid for sperm • Fluid eventually creates semen • Fluid is high in proteins, enzymes, fructose, mucus, vitamin C • The high fructose concentrations provide nutrient energy for the spermatozoa
Prostate Gland • To store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid • Rest of the seminal fluid is produced by the two seminal vesicles • The alkalinity of seminal fluid helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. • Contain smooth muscles that help expel semen during ejaculation. • A healthy human prostate is slightly larger than a walnut • It surrounds the urethra just below the urinary bladder and can be felt during a rectal exam.
Cowper’s Glands • Bulbourethral gland • During sexual arousal each gland produces a clear secretion known as pre-ejaculate. • Fluid helps to lubricate the urethra for spermatozoa to pass through • Helps flush out any residual urine or foreign matter
Epididymis • Where sperm mature and are stored • They lack the ability to swim forward (motility) and to fertilize an egg
Female Reproductive System • Produces female sex hormones • Stores female reproductive cells • Ova (singular, ovum)
Ovaries • Female sex gland • Produce female sex hormones • Store ova (egg) • 400,000 at birth • 1 matures each month • Ovulation – process of releasing a mature ovum into the fallopian tube each month • The right ovary will release a mature ovum one month, and the left ovary will release one the next month.
Fallopian Tubes • A pair of tubes with fingerlike projections that draw in the ovum • Eggs travel from the ovaries to the uterus via the fallopian tubes • Tiny hair-like structures called cilia line the tubes and move egg along • Ectopic pregnancy
Vagina • A muscular, elastic passageway that extends from the uterus to the outside of the body • Sperm from the male enter the female reproductive system through here.
Fertilization • If sperm are present in the fallopian tubes, a sperm cell may unite with an ovum. • Fertilization of an egg by a sperm is called a zygote. • When the zygote leaves the fallopian tube, it enters the uterus. • Attaches itself to the uterine wall and begins to grow.
Uterus • Hollow, muscular, pear-shaped organ • Nourishes and protects the fertilized egg
Menstruation • Each month the uterus prepares for possible pregnancy • If pregnancy doesn’t occur, the thickened lining of the uterus, called the endometrium, isn’t needed, and it breaks down into blood, tissue, and fluids. • These materials pass through the cervix and into the vagina.
Cervix • Opening of the uterus • The lower, narrow portion of the uterus where it joins with the top end of the vagina • It’s a cylindrical shape • During menstruation the cervix stretches open slightly to allow the endometrium to be shed • During childbirth, contractions of the uterus will dilate the cervix up to 10 cm in diameter to allow the fetus to pass through.
Endometrium • Tissue that lines the uterus • Menstrual cycle • Day 1-8: after seven days, if the egg is not fertilized, menstruation begins • Day 9-23: A new egg is maturing inside the ovary • Day 24: The mature egg is released into one of the fallopian tubes • Day 25-28: The egg travels through the fallopian tube to the uterus.
Vulva • The region of the external genital organs of the female, including the: • labia majora • labia minora • clitoris • vaginal orifice