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Learn about the types of asexual reproduction, sexual development in puberty, male and female reproductive systems, menstrual cycle, fertilization, embryonic development, terminology in pregnancy, stem cells, and differentiation. Explore the applications of stem cells for tissue repair and autoimmune diseases.
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BACTERIA YEAST PLANTS Asexual Reproduction • Type of reproduction that each offspring has the same genetic information Where can asexual reproduction be found?
There are 5 different types of asexual reproduction. 1. Budding Parent divides unequally; new individuals develop from buds ex – yeast & hydra 2. Binary Fission Most simple form of asexual reproduction; Parent divides equally and results in two separate individuals (mitosis) Ex.-paramecium 3. Spore Formation Single specialized cells that germinate when released from parent. Usually covered by a protective coating for preservation.
4. Regeneration/fragmentation Ability to regrow new body parts/ability to grow new Organism from parts. ex – hyrda, planaria, starfish, the bad guy from Terminator 2 5. Vegetative Reproduction/Propagation Refers to roots, stems, and leaves. Cells divide then differentiate to produce the same organism Ex.- strawberry plant, pick-a-back plant
Sexual Development • Puberty is a period of rapid growth and sexual maturation during which the reproductive system becomes fully functional. • When puberty ends, reproductiveorgansare fully developed. • Puberty usually begins between the ages of 9 and 15, and usually starts one year earlier in females than in males.
Sexual Development • Puberty begins when the hypothalamussignals the pituitary to produce increased levels of two hormones that affect the gonads. • These hormones are follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
The Male Reproductive System • Release of FSH and LH stimulates cells in the testes (male reproductive organ) to produce testosterone (male hormone). • FSH and testosterone stimulate the development of sperm(male sex cell (gamete).
Head Nucleus • A sperm cell consists of: • a head, which contains the nucleus • a midpiece, which contains energy-releasing mitochondria • a tail, which propels the cell forward Midpiece Mitochondria Tail
The Male Reproductive System • Male Reproductive System Urinary bladder Vas deferens Pubic bone Seminal vesicle Urethra Rectum Penis Prostate gland Epididymis Testis Scrotum
The Female Reproductive System • Puberty in females starts when the hypothalamus signals the pituitary gland to release FSH and LH. • FSH stimulates cells within the ovaries to produce estrogen • The primary female reproductive organ are the ovaries (egg – gamete)
The Female Reproductive System Fallopian tube Ovary Uterus Cervix Urinary bladder Rectum Pubic bone Vagina Urethra
The Menstrual Cycle • The menstrual cycle is controlled by internal feedback mechanisms between the reproductive system and the endocrine system. • The cycle takes an average of 28 days.
The Menstrual Cycle • During the menstrual cycle, an egg develops and is released from an ovary. (ovulation) • The uterus is prepared to receive a fertilized egg. • If the egg is fertilized, it is implanted in the uterus and embryonic development begins. • If the egg is not fertilized, it is discharged and menstruation occurs.
Fertilization and Development of an Offspring • Gametes – reproductive cells (egg and sperm) • When sperm and egg unite, new cell is called zygote • Fertilization occurs in the oviduct (fallopian tubes) • 1st 8 weeks – Embryo • After 8 weeks - Fetus • Development of fetus occurs in uterus
Terminology for Development • Uterus – muscular structure located in female where development occurs • Placenta - an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply • Umbilical Cord – connects baby to placenta of mother • Amniotic fluid – yellowish fluid that surrounds the baby
ZYGOTEThe fertilized egg http://en.wikipedia.org/wiki/Image:Sperm-egg.jpg#file
Mitosis and Differentiation Cell differentiationis how generic embryonic cells become specialized cells http://stemcells.nih.gov/info/scireport/appendixA.asp Image courtesy of NIH resource for stem cell research http://embryo.soad.umich.edu/carnStages/carnStages.html Image courtesy of Brad Smith, University of Michigan
SO…..WHAT ARE STEM CELLS? • Stem cellsare a class of undifferentiated cells that are able to differentiate into specialized cell types • Cells that can become any cell is called pluripotent • Cell that can become almost any cell is called multipotent
WHERE DO STEM CELLS COME FROM? • EMBRYONIC • BLASTOCYST • “ADULT Tissue” • CORD CELLS • PLACENTA • CHILDREN • ADULTS
Stem Cell Applications • Tissue repair - nerve, heart, muscle, organ, skin Cancers • Autoimmune diseases - diabetes, rheumatoid arthritis, MS
Tissue Repair • Regenerate spinal cord, heart tissue or any other major tissue in the body.
Rheumatoid Arthritis • Adult Stem Cells may be helpful in jumpstarting repair of eroded cartilage.
Leukemia and Cancer • Studies show leukemia patients treated with stem cells emerge free of disease. • Injections of stem cells have also reduces pancreatic cancers in some patients. Proliferation of white cells