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REPRODUCTIVE SYSTEM. Male R o Learning OUtcomes. VOCABULARY. _____ HCG _____ Implantation _____ Interstitial cells _____ Labia _____ Leutenizing hormone _____ Luteal phase _____ Menopause _____ Menstrual phase _____ Menstruation (menses) _____ Oogenesis _____ Ova _____ Ovaries
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REPRODUCTIVE SYSTEM
VOCABULARY _____ HCG _____ Implantation _____ Interstitial cells _____ Labia _____ Leutenizing hormone _____ Luteal phase _____ Menopause _____ Menstrual phase _____ Menstruation (menses) _____ Oogenesis _____ Ova _____ Ovaries _____ Oviduct _____ Ovarian cycle _____ Ovulation _____ Oxytocin _____ Pap smear _____ Penis _____ Placenta _____ Pregnancy _____ Progesterone _____ Proliferative phase _____ Prostate gland _____ Puberty _____ Scrotum _____ Secretory phase _____ Semen _____ Seminal fluid _____ Seminal vesicles _____ Seminiferous tubules _____ Spermatogenesis _____ Spermatogonia _____ Spermatozoa (sperm) _____ Testes _____ Testosterone _____ Urethra _____ Uterine cycle _____ Uterus _____ Vagina _____ Vulva _____ Womb _____ Birth canal _____ Buffer _____ Bulbourethral gland _____ Cervix _____ Clitoris _____ Copulation _____ Corpus luteum _____ Cowper’s glands _____ Ductus (vas) deferens _____ Ejaculation _____ Endometrium _____ Epididymus _____ Erectile tissue _____ Estrogen _____ External genitalia _____ Fimbria _____ Follicles _____ Follicular phase _____ FSH ____ GnRH ____ Gonads
INTERESTING FACTS QUIZ: TABOOS AND STRANGE FACTS http://www.livescience.com/php/trivia/index.php?quiz=sex&qnum=1&count=10&score=0&correct=&q_or_a=0&submit.x=123&submit.y=7 Lots of hanky panky. On any given day, sexual intercourse takes place 120 million times on earth. Humans are a quickly proliferating species, and with about 4% of the world’s population having sex on any given day, it’s no wonder that birth rates continue to increase in many places all over the world. Fertility facts. The largest cell in the human body is the female egg and the smallest is the male sperm. While you can’t see skin cells or muscle cells, the ovum is typically large enough to be seen with the naked eye with a diameter of about a millimeter. The sperm cell, on the other hand, is tiny, consisting of little more than nucleus. Dreams of pregnant women. The three things pregnant women dream most of during their first trimester are frogs, worms and potted plants. Many women also dream of water, giving birth or even have violent or sexually charged dreams.
INTERESTING FACTS Teething in the womb. Your teeth start growing 6 months before you are born. While some babies are born with teeth in place, the tooth buds that will eventually become teeth in young children (during their 1st year of life) are formed at 9 to 12 weeks in utero. All the blue-eyed babies. Babies are always born with blue eyes. The color of your eyes depends on the genes you get from your parents, but at birth most babies appear to have blue eyes. The reason behind this is the pigment melanin. The melanin in a newborn’s eyes often needs time after birth to be fully deposited or to be darkened by exposure to ultraviolet light, later revealing the baby’s true eye color. All the strong babies. Babies are, pound for pound, stronger than an ox. While a baby certainly couldn’t pull a covered wagon at its present size, if the child were the size of an oxen it just might very well be able to. Babies have especially strong and powerful legs for such tiny creatures, so watch out for those kicks.
INTERESTING FACTS Infants with teeth. One out of every 2,000 newborn infants has a tooth when they are born. Nursing mothers may cringe at this fact. Sometimes the tooth is a regular baby tooth that has already erupted and sometimes it is an extra tooth that will fall out before the other set of choppers comes in. A fetus with fingerprints. A fetus acquires fingerprints at the age of three months. At only 6-13 weeks of development, the whorls of what will be fingerprints have already developed. Oddly enough, those fingerprints will not change throughout the person’s life and will be one of the last things to disappear after death. Single-celled people. Every human spent about half an hour as a single cell. All life has to begin somewhere, and even the largest humans spent a short part of their lives as a single celled organism when sperm and egg cells first combine. Shortly afterward, the cells begin rapidly dividing and begin forming the components of a tiny embryo.
HUMAN REPRODUCTION The goal of the reproductive system is to pass on your genetic code onto a new and unique generation. This is ultimately accomplished via fertilization.
Terms you should know: • Haploid • Diploid • Zygote • Gamete • Gonad • Label these on the diagram Human Life Cycle
HUMAN REPRODUCTION Human reproduction employs internal fertilization, and depends on the integrated action of hormones, the nervous system, and the reproductive system. Male gonads are the testes, which produce spermand testosterone. Female gonads are the ovaries which produce eggs and 2 hormones: estrogen estrogen and progesterone.
MALE REPRODUCTION Male Anatomy The male external genitalia are the scrotum and penis. The scrotum is a fold of skin that encloses the male gonads (testes)
MALE REPRODUCTION scrotum testes
MALE REPRODUCTION Male fruit bat of the species Rousettus aegyptiacus have testes that are 2.15 % of body mass, whereas their brains are only 1.70 %. The males in some bat species can have testes that are up to 8.5 % of their body mass.
MALE REPRODUCTION The testes are a pair of tightly coiled tubes surrounded by several layers of connective tissues. These tubes are the SEMINIFEROUS TUBULES, where sperm are produced by meiosis. About 250 meters of tubules are packed into each testis.
MALE REPRODUCTION The INTERSTITIAL CELLS are scattered between the seminiferous tubules in the testes. These cells produce testosterone.
MALE REPRODUCTION Sperm production cannot occur at normal body temperature. So just before birth, the testes descend to hang outside the abdominal cavity in the scrotum, a fold of skin. The temperature in the scrotum is ~2oC below body temperature.
MALE REPRODUCTION SPERMATOGENESIS This, the production of mature sperm cells, is a continuous and prolific process in the adult male. Spermatogenesis occurs in the seminiferous tubules of the testes. The spermatogonia undergo repeated mitoses to produce large numbers of potential sperm or spermatocytes (approximately 3 million/day).
MALE REPRODUCTION SPERMATOGENESIS Next, Meiosis occurs to create 4 haploid spermatids. The sertoli cells transfer nutrients to the spermatids, and the developing sperm are gradually pushed toward the center of the seminiferous tubule and make their way to the epidymis. When the spermatids reach the epidymis, they acquire motility (mature), and are stored.
MALE REPRODUCTION SPERMATOGENESIS The process from spermatogonia to motile sperm, takes 65-75 daysin the human male. Each ejaculation of a human male contains about 400 million sperm cells. Sperm production begins at pubertyand continues throughout life, with several hundred million sperm being produced each day.
MALE REPRODUCTION SPERM CELLS The structure of a sperm cell fits its function. The thick head contains the haploid nucleus and is tipped with a special body, the acrosome. The acrosome contains enzymesthat help the sperm penetrate the egg. The neck contains large numbers of mitochondria that provide ATP for movement. The tail is a flagellum which moves the sperm.
MALE REPRODUCTION During ejaculation, the sperm are propelled from the epididymis through the muscular VAS DEFERENS ducts, which run from the scrotum around and behind the bladder, where they join to form a short EJACULATORY DUCT. This duct opens into the URETHRA, the tube which drains both the excretory and reproductive systems (never both at the same time). The urethra runs through the penis and opens to the outside at the tip of the penis.
MALE REPRODUCTION • In addition to the testes and ducts, the male reproductive system contains three sets of glands that add their secretions to the SEMEN (the fluid ejaculated). • SEMINAL VESICLES: contribute about 60% of the total volume of semen. This pair of glands lies below and behind the bladder and empties into the ejaculatory duct. The fluid is thick and clear and contains mucous, amino acids, and large amount of fructose (which provides energyfor the sperm). These vesicles also secrete PROSTAGLANDINS, which once in the female reproductive tract, stimulate contractions of the uterine muscles that help move the semen up into the uterus. Proteins in the seminal fluid cause the semen to coagulate after it is deposited in the female, thus, making it easier for uterine contractions to move the semen.
MALE REPRODUCTION • PROSTATE GLAND: • This is the largestof the accessory glands. • Prostatic fluid is thin, milky, and quite alkaline, which balances the acidity of any residual urine in the urethra and the natural acidity of the vagina.
MALE REPRODUCTION • PROSTATE GLAND: • This gland is the sources of some of the most common medical problems of men over 40. • A benign enlargement of the prostate occurs in more than ½ of all men in this age group. • That is why it is important to get tested annually after the age of 40.
MALE REPRODUCTION • BULBOURETHRAL GLANDS (cowper’s gland): • These are a pair of small glands along the urethra below the prostate. • They secrete a viscous fluid before emission of the semen. • It has been suggested that this fluid lubricates the penis and vagina, but the volume (just one or two drops) seems insufficient to be very effective for this function. This fluid does carry some spermreleased before ejaculation,. This is one factor in the low success rate of the withdrawal method of birth control.
MALE REPRODUCTION The penis is composed of spongy tissue derived from modified veins and capillaries. During sexual arousal, this erectile tissue fills with blood from the arteries. As it fills, the increasing pressure seals off the veins that drain the penis, causing it to engorge with blood.
MALE REPRODUCTION The resulting erection is essential to insertion of the penis into the vagina (rodents, raccoons, walruses, and several other mammals also possess a baculum, a bone that stiffens the penis).
MALE REPRODUCTION It is a baculum, or penis bone, of an extinct species of walrus. The 12,000 year old fossil was discovered in Siberia. What remains is a 4 ½ foot piece of dry muscle tissue and weathered skin.
