Animal Reproduction and Development Flashcards
~Asexual Reproduction
● Produced offspring genetically identical to the parent
● Includes budding, fragmentation/regeneration, parthenogenesis
~Budding
● Involves the splitting off of new individuals from existing ones
● Hydra
~Fragmentation and regeneration
● Occurs when a single parent breaks into parts htat regenerate into new individuals
● Sponges, planaria, starfish
~Parthenogenesis
● Involves the development of an egg without fertilization
● Resulting adult is haploid
● Honeybee, whiptail lizards
~Sexual reproduction
● Each offspring is the product of both parents
~Epididymis
● Tube in the testes where sperm gain motility
~Leydig cells
● Clusters of cells located between seminiferous tubules that produce testosterone
~Prostate gland
● Large gland that secrete semen directly into the urethra
~Scrotum
● Sac outside the abdominal cavity that hodes the testes
● Cooler the temperature there enables sperm to survive
~Seminal vesicles
● Secrete mucus, fructose sugar (which provides energy for the sperm) and the hormone prostaglandin during sexual intercourse
~Prostaglandin
● Stimulates uterine contractions
~Seminiferous tubules
● Sites of sperm formation int he testes
~Sertoli cells
● Provide nutrients for developing sperm
~Testes/testis
● Male gonads, where sperm are produced
~Urethra
● Tube that carries semen and urine
~Vas dferens
● Muscular duct that carries sperm during ejaculation from the epididymis to the urethra in the penis
~Ovaries
● Where meiosis occurs
~Oviducts/Fallopian tubes
● Where fertilization occurs
● After ovulation, the egg moves through the oviduct to the uterus
~Uterus
● Where blastocyst will implant and where the embryo will develop during the nine-month gestation if fertilization occurs
~Endometrium
● Lining of the uterus that thickens monthly in preparation for implantation of the blastocyst
~Vagina
● Birth canal
● During labor and delivery, the baby passes through the cervix and into the vagina
~Cervix
● The mouth of the uterus
~Follicular phase
● Several follicles in the ovaries grow and secrete increasing amounts of estrogen in response to follicle-stimulating hormone (FSH) from the anterior pituitary
~Ovulation
● Secondary oocyte ruptures out of the ovaries in response to luteinizing hormone
~Luteal phase
● Corpus luteun forms in response to luteinizing hormone
● It is the follicle left behind after ovulation and secretes estrogen and progesterone, hwich thicken the endometrium of the uterus
~Menstruation
● The monthly shedding of hte lining of the uterus when implantation of an embryo does not occur
~Positive feedback in the menstrual cycle
● Enahces a process until it is completed
● During the follicular phase, estrogen released from the follicle stimulates hte release of LH from the anterior pitruitary
● The increase in LH stimulates the follicle to release even more estrogen
● The hormone levels continue to rise until the follicle matures and ovulation occurs
~Negative feedback in the menstrual cycle
● Stops a process once homeostasis is reached
● During the luteal phase, LH stimulates the corpus luteum to secrete estrogen and progesterone
● Once the levels of estrogen and progesterone reach sufficiently high levels, they trigger the hypothalamus and pituitary to shut off, thereby inhibiting the secretion of LH and FSH
~Spermatogenesis
● Process of sperm production
● Contiuous process that starts at puberty
~Oogenesis
● Production of ova
● Begins prior to birth
● Within the embryo, an oogonium cell (2N)
- These remain quiescent within small follicles in the ovaries until puberty, when they become reactivated by hormones
● FSH periodically stimulates the follicles to complete meiosis I, producing secondary oocytes (N), which are released at ovulation
● Meiosis II then stops again and does not continue until fertilization, when a sperm penetrates the secondary oocyte
~Fertilization
● Fusion of pserm and ovum nucleic
● Begins with the acrosome reaction
● Specific recognition
~Acrosome reaction
● The head of the sperm (acrosome) releases hydrolytic enzymes that penetrate the jelly coat of the egg
● Specific molecules from the sperm bind with receptor molecules on the vitelline membrane before the sperm come in contact with the ovum’s plasma membrane
~Specific recognition
● Ensures that the egg will be fertilized by only sperm from the same species
~Fast block to polyspermy
● Lasts only a minute but just long enough to allow the slow block to polyspermy
● Once a sperm binds to receptors ont he egg, the membrane is dramatically depolarized and no other sperm can penetrate the egg membrane