. THE REPRODUCTIVE SYSTEM WHAT IS THE REPRODUCTIVE SYSTEM? The reproductive system is the structural and physiological network whose purpose is the creation of a new life to continue the species. It is the only body system which is not concerned with supporting the life of its host. Two types of reproduction: Asexual and Sexual
Asexual reproduction is far less common in animals, but does occur. Ex. Hydra Sexual reproduction involves male + female, asexual does not ASEXUAL REPRODUCTION Advantageous for organisms who rarely encounter mates Asexual reproduction: does not involve meiosis
or fertilization. Involves 1 parent Primary reproduction in single-celled organisms archaea, bacteria, protists Includes binary fission, bacterial conjugation, fragmentation/regeneration and budding, parthenogenesis ASEXUAL REPRODUCTION
Binary Fission: Cell splits, replicated DNA divided evenly between both daughter cells Bacterial Conjugation: Bacteria shoots out a tube and injects piece of its DNA into another bacteria Fragmentation + Regeneration: body of parent breaks down, offspring arise and regrowth of lost body parts Ex. Fungi Budding: Offspring grow out of parent Ex. Yeast, hydra Parthenogenesis is the development of a new individual from an unfertilized egg SEXUAL REPRODUCTION
Fusion of female gamete (egg) and male gamete (sperm) to form a zygote Includes meiosis and fertilization Involves both a male and female counterpart External fertilization: eggs are shed by the female and fertilized by the male, occurs mainly in moist environments Internal fertilization: occurs when sperm are deposited in female reproductive tract & sperm and egg are united SEXUAL REPRODUCTION
Sexual Reproduction is difficult for organisms who rarely encounter a mate Hermaphroditism is an evolutionary solution among sessile, burrowing, and other organisms lacking locomotion Hermaphrodites have both male and female reproductive systems Each animal donates and receives sperm during mating-Any two individuals can mate ADVANTAGES OF SEXUAL REPRODUCTION
An increase in variation of offspring which results in greater reproductive success in changing environments An increase in the rate of adaptation A shuffling of genes to eliminate harmful genes from a population GAMETOGENESIS
Process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes. Spermatogenesis: the production of mature sperm cells, occurs in the seminiferous tubules of the testes Oogenesis: the development of the ova (mature unfertilized eggs), occurs in the ovarian follicle of ovary PHYLA CNIDARIA Hydra Vulgaris A freshwater cnidarian Exists only in polyp form and reproduces asexually by budding Relatively simple reproductive system
Advantages/ adaptations: hydra bud asexually when food is available. Can form many new organisms quickly. Hydra do not move around much, it is much more efficient than finding a mate + conserves energy. PHYLA ANNELIDA
Lumbricus Terrestris: (common earthworm) They are hermaphrodites but cross-fertilize Some reproduce sexually by fragmentation Advantages/ adaptations: Earthworms are slow moving, finding mates is not always easy. Having the ability to reproduce without a partner allows the worm to reproduce if conditions do not permit
finding of a mate. PHYLA ARTHROPODA Belostoma Flumineum Fewer offspring than most insects because of increase in parental care Complex reproductive systems Advantages/Adaptations: Eggs are laid on the
back of the males, who care for them until they hatch. Females actively search for mates. PHYLA MAMMALIA -HOMO SAPIENS FERTILIZATION OF AN EGG BY SPERM - CONCEPTION OCCURS IN THE OVIDUCTS FEMALE REPRODUCTIVE CYCLES Two types of cycles occur: menstrual and estrous Menstrual: The endometrium is shed from the uterus in a bleeding called menstruation (sexual receptivity is not limited to a specific timeframe) - If an embryo has not implanted in the endometrium by the end of the secretory phase a
new menstrual flow begins --Estrous: The endometrium is reabsorbed by the uterus (sexual receptivity is limited to a heat period) Menopause= cessation of ovulation and menstruation between the ages of 46 and 54 -Hormones coordinate the menstrual and ovarian cycles so that growth of the follicle and ovulation are synchronized with preparation of the uterine lining for a
possible embryo - Five hormones participate: - GnRH - FSH - LH - Estrogen WHY IS THE REPRODUCTIVE SYSTEM NECESSARY? Reproductive system provides a way to
produce and transport gametes Maximizes survival of offspring while in embryonic state Provides environment for growth of offspring (womb) Needed for species continuation/adaptation INTERDEPENDENCE OF REPRODUCTIVE SYSTEM All body systems are dependent on one another The reproductive system is governed
by the nervous/endocrine systems, determine when/ how many gametes produced + regulate cycles Maternal arteries Maternal veins Placenta Maternal portion of placenta Umbilical cord
Umbilical cord Umbilical arteries Umbilical vein Requires nutrients be transported to via the cardiovascular system -Oxygen from the respiratory system -Digestive system supplies nutrients needed to maintain gamete production/facilitate pregnancy (women) DISEASES/DISORDERS OF THE REPRODUCTIVE SYSTEM
Disease/disorder that negatively impacts an aspect of reproductive system: ability to produce gametes, ability to transport gametes, etc. Any disease or injury to the body not only the reproductive system- could potentially harm the fetus during development. Female Reproductive Disorders: Premenstrual Syndrome, Ovarian Cysts, Endometriosis, Uterine Leiomyomas, Female Infertility , Pelvic Inflammatory Disease Male Reproductive Disorders: Testicular Cancer, Infertility, Erectile Dysfunction,
MALE INFERTILITY Approximately 15% of couples are infertile.Mayoclinic Male infertility inability of the male to achieve pregnancy in fertile female. Causes: abnormal sperm production/function, problems with delivery (sexual function), environmental/lifestyle factors/age Symptoms: inability to conceive child, pain/swelling in testicular area, decreased facial/body hair/ other signs of chromosomal
or hormonal abnormality MALE INFERTILITY Tests Include: Semen Analysis- checks for number/ abnormalities of sperm Ultrasound check for blockages/ check prostate Vasography contrast dye injected into vas deferens, checks for blockages Cures: Surgery remove blockage, correct abnormalities Treating Infections infections can take hold in reproductive tract, can be cured but fertility cannot always be restored TESTICULAR CANCER
Cancer that starts in the testicles, the male reproductive glands located in the scrotum. Causes: Abnormal testicle development Klinefelter Syndrome presence of extra X chromosome in male Exposure to toxins HIV infection TESTICULAR CANCER Two main types: Seminomas and nonseminomas Seminoma slow growing, usually found in men during 30s or 40s. Cancer usually found in testes,
can spread to lymph nodes. Very sensitive to radiation. Nonseminoma- More common, tend to grow more quickly than nonseminomas. Composed of different types of cells, identified according to these different types: | Choriocarcinoma | Embryonal Carcinoma | Teratoma | Yolk Sac Tumor | TESTICULAR CANCER Symptoms: Discomfort or pain in testicles, feeling of heaviness in scrotum
pain in lower back/abdomen Enlargement of testicle/change in feeling of testicle Gynecomastia (excess development of breast tissue in males) Lump or swelling in either testicle TESTICULAR CANCER Tests:
blood tests for tumor markers Chest x-ray Abdominal/pelvic CT scan Ultrasound of scrotum Cures: like all cancers depends on type/stage of cancer Surgical Treatment removal of cancer Radiation Therapy
Chemotherapy medications such as cisplatin, bleomycin, and etoposide used to kill cancer cells THE REPRODUCTIVE SYSTEM: SUMMARY Two types: Asexual vs Sexual Asexual = 1 parent, does not involve meiosis or fertilization. Offspring same as parent. Advantage: diverse mechanisms of asexual reproduction enable animals to produce identical offspring rapidly Sexual = 2 parents (male and female), Advantage: results in genetically diverse offspring that can adapt to the environment SUMMARY CONT. Reproductive systems have evolved differently in many animal phyla
These systems range from the production of gametes by undifferentiated cells to complex structural assemblies of gonads with accessory tubes and glands WORKS CITED http://
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