Reproduction(Day 1)

1. Reproduction(Day 1) Raymundo Jaime Jose Cuevas

2. Animal Reproduction • Asexual reproduction • Only one parent • Efficient Strategy - Although there is the advantage of this type of reproduction is beneficial for certain animals that are unable to look for mates and ideally “costs” the parent les energy and time, the disadvantage is that there is a lack of genetic variation. • Cnidarians (hydras) produce by budding • Annelids (earthworms and sandworms) by regeneration from fragments

3. Fragmentation: the body of the parent breaks into distinct pieces, each of which can produce offspring • Regeneration: piece of a parent is detached and can develop into a completely new individual

4. Animal Reproduction • Flatworms, roundworms, crustaceans, annelids, insects, fishes, lizards, and some turkeys can reproduce parthenogenetically, parthenogenesis is a modification of sexual reproduction in which an unfertilized egg develops into a complete individual • 1.Facultative • 2.Obligate

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6. Animal Reproduction • Sexual reproduction • Egg is fertilized by sperm of another • Dioecious, two separate sexes • Monoecism (hermaphroditic) have female and male boy parts • Sex reversal- coral reef fishes called wrasses; male has a harem of several females, when the male dies, one of the females become male.

7. Animal reproduction • Animals produce gametes ( a mature male or female germ cell possessing a haploid chromosome) in specialized organs called gonads • Testes produce sperm • Ovaries produce eggs The egg is fertilized with the sperm, and can be done in different forms, such a external fertilization or through copulation

8. Animal Reproduction Viviparous (producing living young instead of eggs) • Placental mammals • Placenta Oviparous • Animals that deposit an egg in the external environment • larva Ovoviviparous • Animals that retain their eggs in some way and release young able to fend for themselves • Oysters • Male sea horses

9. In vitro fertilization (IVF) • The process by which an egg is fertilized by sperm outside the body • It involves monitoring the woman’s ovulatory process, removing an ovum or ova (eggs) from the ovaries and letting sperm fertilized them in a fluid medium in a laboratory. • Potential Risks and variation of views on IVF

10. SENSITIVE MATERIAL AHEAD

11. Human Male Reproduction • The testes produce gametes • A series of ducts store and transport the sperm • The accessory glands produce the fluid portion of semen • The penis transfers the sperm through copulation to the female • Hormones

12. Human Male Reproduction

13. Spermatogenesis • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter28/animation__spermatogenesis__quiz_1_.html • The basic function of spermatogenesis is to turn each one of the diploid spermatogonium (tiny tubules containing diploid cells) into four haploid sperm cells. • This is accomplished through meiotic cell division • FSH (secreted by the pituitary) stimulates primary spermatocytes to undergo the first division of meiosis. • LH (also secreted by the pituitary) stimulates the secretion of testosterone by the testes • Testosterone (secreted by interstitial cells) stimulates secondary spermatocytes to develop into sperm.

14. Human Male Reproduction (testes) • Leydig cells (interstitial cells)   • release the male sex hormones (Androgens) • Germinal epithelium cells • Wall of the seminiferous tube • Place of sperm production • Sertoli cells • Nourish the developing sperm cell • Called the “nurse” cell • Developing spermatozoa (motile sperm cell)

15. Human Male Reproduction

16. Male Reproductive System

17. Sperm

18. Testosterone • Three roles of testosterone in males • Development of male genitalia (in the fetal stage) • Maintenance of sex drive and happiness • Development of male secondary sexual characteristics at puberty (growth of facial hair, deepening of the voice, initiation of sperm production)

19. Day Two

20. Spermatogenesis

21. Human Female Reproduction • The females' reproductive system is adapted to produce eggs, receive the penis and sperm, and protect and nourish the embryo during and after pregnancy • The ovaries produce gametes and sex hormones • The oviducts transport the secondary oocyte • The uterus incubates the embryo • The vagina receives sperm • The vulva are external genital structures • The breasts function in lactation

22. Female Reproductive System

24. Female Reproductive Organs

25. Ovary • Location: on the lateral wall of the pelvis • Oocyte: The oocyte is a female germ cell that is not yet ready for fertilization.  The oocyte matures into an ovum (egg) that will be released during ovulation. • Germinal epithelium: layer of simple epithelial cells covering the ovary • Primary follicles: is an immature follicle consisting of the oocyte surrounded by a single layer of cells • Mature follicles: a follicle that is ready for ovulation • Secondary Oocyte: will be produced when the primary oocyte completes meiosis. Will talk about later in menstruation cycle

26. Ovary

27. Oogenesis

28. Egg

29. Spermatogenesis vs. Oogenesis Gametes • Spermatogenesis: • Four are made from a spermatogonium • continuous production • Although from puberty to old age sperm cells are constantly being engendered, the production is subject to extreme fluctuation regarding both quantity and quality. • Oogenesis: • Only one made from primary oocyte, once a month • Exhaustion of the supply at menopause

30. Menstrual Cycle • http://www.youtube.com/watch?v=nwo9KSNwSjE • The menstrual cycle is the scientific term for the physiological changes that occur in fertile women and other female primates for the purposes of sexual reproduction. • It is commonly divided into three phases: the follicular phase, ovulation, and the luteal phase. - It begins with the formation of the corpus luteum (the cells that surrounds the egg while it was in the ovary) and ends in either pregnancy or luteolysis (structural and functional degradation of the corpus luteum)

32. Hormones During the Menstrual Cycle

33. Control of Human Reproduction • Intrauterine devices • Mechanically prevent implantation, and can contain progesterone to prevent ovulation, prevent implantation and thicken cervical mucus • Hormone Skin Patches • Same as oral contraceptives • Depo-Provera • Shot of progesterone • Diaphragm and Spermicidal jelly • Latex cup that covers the cervix • Female and Male Condoms • Implant • Implanting of progesterone under skin • Birth Control • Combined action of estrogen and progesterone • “Morning after” pill

34. Reproductive technologies • Artificial Insemination by Donor (AID) • Sperm is placed in the vagina by a physician • In Vitro Fertilization (IVF) • “In Glass” fertilization • Gamete Intrafallopian Transfer (GIFT) • Exactly the same of IVF, but oocytes and sperm are placed in the oviducts immediately after being brought together • Surrogate Mother • Intracytoplasmic Sperm Injection (ICSI) • Single sperm is injected into an oocyte

35. Acquired Immunodeficiency Syndrome (AIDS) • Cause • Human Immunodeficiency Virus (HIV) • Attacks helper T cells • Symptoms • Categories A, B, and C • A- last about a year, no symptoms but still passes it on • B- may last six to eight years, lymph nodes swell, and the person may experience weight loss, night sweats, fatigue, fever, and diarrhea • C- full-blown AIDS, nervous disorders and the development of an opportunistic disease, such as an unusual type of pneumonia or skin cancer • Transmission • Sexual contact • Needle-sharing • Transfusions of infected blood • Treatment • No cure • Drug cocktail

36. Other STDs • Genital Warts • Caused by the human papillomaviruses (HPVs) • Flat or raised warts on the penis and foreskin of males and the vaginal orifices and cervix of females • No cure, but treated by surgery, freezing, application of an acid and lasers • Vaccination for most common HPV has been made • Genital Herpes • Caused by herpes simplex virus • Type one causes cold sore and fever blisters • Type two cause genital herpes • Crossover infections can happen • Blisters on genitals • Can be accompanied by fever, pain on urination, swollen lymph nodes, and a copious discharge in the ladies • Blisters rupture and form ulcers • Hepatitis • Several types, all infect the liver and can cause death and cancer • Hepatitis A is caused by drinking sewage-contaminated water, sexually transmitted through oral or anal contact • Hepatitis B is spread by the same manner as AIDS, and is more infectious • Hepatitis C is called posttransfusion hepatitis but can be spread by sexual contact • Vaccine for B, none for C

37. Other STDs (cont) • Gonorrhea • Caused by the bacterium Neisseria gonorrhoeae • Typical symptoms for males are pain upon urination and a thich, greenish yellow urethral discharge • Latent infection leads to pelvic inflammatory disease (PID) • Syphilis • Caused by the bacterium Treponemapalidum • Primary stage- a hard chancre (ulcerated sore with hard edges) appears • Secondary stage- a rash appears all over the body • Tertiary stage- affects the cardiovascular and/or nervous system • Infected person may become mentally retarded, become blind, walk with a shuffle, or show signs of insanity • Bacterial Vaginosis • Trichomoniasis • Chlamydia • Caused by the bacterium Chlamydia trachomatis • After about 8-21 days of infection, men may experience a mild burning sensation on urination and a muciod discharge • Women have a vaginal discharge alone with the symptoms of a urinary tract infection

38. GRAND FINALE

39. Fertilization • The union of a sperm and an egg to form a zygote. • Egg is covered by sperm, secret enzymes weaken the corona radiata • After weaken enough, they squeeze through and then bind to the zonapellucida • Acrosome Reaction: • Acrosome: organelle that develops over the anterior half of the head in sperm cells. (cap-like structure) • The acrosome release digestive enzyme that forge a pathway for the sperm through the zonapellucida to the oocyte plasma membrane

40. Fertilization (cont) • When the sperm is attached too the oocyte, events happen to prevent polyspermy • The oocyte’s plasma membrane depolarize and change in charge, “fast block” • Vesicles in the oocyte called cortical granules secrete enzymes that turn the zonapellucida into an impenetrable fertilization membrane, “slow block”

41. Fertilization (cont) • Last events lead to the formation of the diploid zygote • Microvilli from the plasma membrane of the oocyte bring the sperm in • Sperm nucleus release its chromatin • Reforms into chromosomes enclosed within the sperm pronucleus • Secondary oocyte completes meiosis • Chromosomes are also enclosed in a pronucleus • Singular nuclear envelope soon surrounds both sperm and egg pronuclei • The two haploid sets of chromosomes share the first spindle apparatus of the fertilized egg, called a zygote

43. Fertilization, simplified • Sperm makes its way through the corona radiata • Acrosomal enzymes digest a portion of zonapellicuda • Sperm biinds to and fuses with oocyte plasma membrane • Sperm nucleus enters cytoplasm of oocyte • Cortical granules release enzymes; becomes fertilization membrane • Sperm and egg pronuclei are enclosed in a nuclear envelope

44. Embryonic Development • Cellular stages of development • Cleavage resulting in a multicellular embryo • Cleavage is cell division without growth • Only increases the number of cells, does not change the original volume of the egg’s cytoplasm • Formation of the blastula • Order of development • Zygote • Morula (ball of cells) • Blastula (hollow ball of cells having a fluid filled cavity called a blastocoel)

45. Embryonic development • Tissue stages of development • The early gastrula • Begins when cells begin to push, invaginate, into the blastocoel, creating a double layer of cells • Has two layers of cells • Ectoderm- outer layer of cells • Endoderm- inner layer of cells • The pore made by invagination is the blastopore • The last gastrula • Gastrulation is not complete until three layers of cells that will develop into adult organs are produced • The late gastrula has a middle layer of cells called the mesoderm

47. Embryonic Development • Organ stage of development • The organs of an animal’s body develop from the three embryonic germ layers • The mesoderm cells lie along the main longitudinal axis of the animal and unite to form a dorsal supporting rod called the notochord • In vertebrates, the notochord is later replaced by the vertebral column • The nervous system develops from the midline ectoderm • Thickening of cells begins, called the neural plate • Then neural folds develop on either side of a neural groove, becomes the neural tube • Embryo is now called a neurula • Midline mesoderm cells that did not contribute to the formation of the notochord now become two longitudinal masses of tissue • Form into somites, give rise to muscles associated with the axial skeleton and the vertebrate • Primitive gut tube is formed by endoderm as the body itself folds into a tube • Heart also begins as a simple tubular pump

48. Developmental Processes • Development requires: • Growth • Cellular Differentiation • Cells become specialized in structure and function • Morphogenesis • The shape and form of the body is produced • Includes pattern formation, how tissues and organs are arranged in the body • Apoptosis is important to pattern formation

49. Cellular Differentiation • Cytoplasmic Segregation • Maternal determinants are in the egg, influence the course of developments • Induction • The ability of one embryonic tissue to influence the development of another tissue • Example, experiment was done with notochord tissue being cut out and transplanted into different places • Cut out and transplanted to the belly region, and the neural tissue began to grow around it

50. Human Embryonic and Fetal Development • Separated into two different time periods • Embryonic period • Months 1 and 2 • Major organs are formed • Fetal development • Months 3 to 9 • Organs are defined