Chapter 43
What is menopause and why is it necessary in the female reproductive process?
Menopause is when women approach their mid-40s to mid-50s, and their ovaries begin to lose their sensitivity to FSH and LH, their menstrual periods become less frequent and finally cease. Child birth at a later age may have more risks and they have decreasing levels of estrogen so this process prevents risk.
How does oogenesis differ from spermatogenesis?
Oogenesis is the production of eggs, while spermatogenesis is the production of sperm cells. Oogenesis also occurs in females, while spermatogenesis occurs in males.
What is oogenesis? Where does it occur? Describe the process.
Oogenesis is the production of eggs. It occurs in the outermost layers of the ovaries. This process starts with a germ cell, called an oogonium, but this cell undergoes mitosis to increase in number, eventually resulting in up to about one to two million cells in the embryo.
List and explain 3 Asexual Reproduction strategies. (types of asexual reproduction)
Binary fission is the bacteria cell replicates all of its DNA, sends part to each side of the cell and divides in half. Regeneration/Fragmentation is when a part/piece of the organism is cut off or removed and they regrow that missing part, and sometimes that missing part can regrow into a new organism. There are also cases where they can split down the middle and form two separate organisms. Budding is when a nob of tissue forms on the side of an organism, and it grows into more tissue, and eventually the tissues differentiate and organize into a miniature version of the adult, pinches off and separates from the organism to form a new organism.
Trace the pathway of an secondary oocyte/"egg" from its release from an ovary to its site of fertilization and then the site of embryo implantation.
Ovaries produce eggs and then later travel to the Fallopian tube (site of fertilization) which connects the ovaries to the uterus, the egg then travels to the uterus (site of implantation) where the fertilized egg will embed itself into the uterine wall and it expands as the egg develops into an embryo.
What is Hermaphrodism and provide examples of organisms that uses this sexual repro. strategy?
Hermaphrodism is when the adult has both male and female reproductive structures. Earth worms utilize hermaphrodism, as they cross fertilize and exchange sperm cells, and each worm holds and stores the cells until the ovaries mature and produce eggs so they are able to use the sperm cells to produce offspring.
Compare/Contrast Asexual Reproduction to Sexual Reproduction.
In asexual reproduction there are no gametes involved, it's common in stable, consistent habitats, it involves the production of offspring with genes all from one individual without the fusion of gametes, and the offspring are genetically identical. In sexual reproduction there are gametes involved, it is common in dynamic or unstable habitats, it involves the production of gametes and fertilization to form offspring, and the offspring are genetically variable,
What are the pros & the cons of the following two Sexual Reproductive strategies: internal fertilization vs. external fertilization.
Internal fertilization creates more gametes and offspring but has less parental care. External fertilization has more parental care but less gametes and offspring.
What hormone "communicates" between the mother and the embryo in order to let the mothers' reproductive system know that an embryo has been produced and needs to be maintained?
LH
What are the female reproductive organs and what is the function of each.
Ovary produces female gamete (eggs) and female hormones (estrogen and progesterone). Oviducts or fallopian tubes are the site of fertilization. Uterus houses developing embryo/fetus. Cervix is the muscular narrow neck of the uterus. Vagina is the repository for sperm or semen. Vestibule covers the vagina opening.
What is Parthenogenesis and provide example of an organism that uses this sexual repro. strategy?
Parthenogenesis is when the unfertilized egg develops into offspring. Honey bees utilize parthenogenesis, as the queen produces a diploid fertilized egg that develops into a female worker and a haploid unfertilized egg that develops into a male.
Where is the site of fertilization on an "egg"?
Plasma membrane
Compare Protandrous Hermaphrodism to Protogenous Hermaphrodism.
Protandrous hermaphrodism is when an organism is male first and female second after maturity. Protogenous hermaphrodism is when an organism is female first and male second after maturity.
What are the hormones associated with male reproduction? Where are they produced and What are the functions of each? (Outline the hormonal control in the male)
Releasing hormone is produced in the hypothalamus and it stimulates anterior pituitary. Follicle stimulating hormone is produced in the anterior pituitary and it stimulates sperm production. Luteinizing hormone is produced in the anterioir pituitary and it stimulates testes to produce testosterone. Testosterone is produced in the testes and it stimulates sperm production and the development of secondary sex characteristics.
Compare/Contrast the Ovarian Cycle to the Uterine Cycle.
The ovarian cycle involves the changes that occur in the follicles of the ovary and the uterine cycle involves the changes in the endometrial lining of the uterus. They are both involved in the menstrual cycle of the female reproductive system.
What is a placenta and briefly describe its structure and function.
The placenta is the organ of exchange between a fetus and a mother. The fetal side is constructed from Chorion. The maternal side is constucted from endometrium. Nutrients and waste products are exchanged between the fetus and the mother within the placenta.
Describe the process and products/results of the Uterine Cycles' Menstrual Flow Phase, Proliferation Phase and the Secretory Phase.
The proliferation phase is the first 2 weeks of the cycle. It involves the rebuilding and thickening of the endometrial lining of the uterus. The secretory phase is the other 1 week. It involves the thickening of the endometrium, the vascularization of the endometrium, and the secretion of glycogen onto the endometrium.
Human gestation consists of 3 stages. List and describe the events occurring in these 3 trimesters
.1st trimester is the first 13 weeks, the pregnancy begins after the first day of the last menstrual period, ball of cells forms and develops into an embryo in the uterus, major systems and structures develop, heart beats at a regular rhythm, embryo is considered a fetus and all jey body parts are present, tissues, kidneys, brain, liver and intestines begin to function, fetus is able to swallow and external genitals have formed. The second trimester is from 14-27 weeks, fetus develops lanugo, doubles in size and weight, fetal movements begin, organs and structures have been formed, facial structures are more distinct, brain is growing rapidly, lungs develop surfactant, fetus begins to exhale and inhale. The third trimester is from 28-40 weeks, breathing and body temperature are controlled by CNS, major fetal development is complete, rapid weight gain, bones are hardening, liver can process some waste, fat develops under skin, fetus is fully developed.
Fertilization-
Acrosomal reaction, fast block to polyspermy, and Cortical reaction, slow block to polyspermy. Sperm makes contact with the egg, acrosome reacts with zona pellucida and perivitelline space, plasma membranes fuse, sperm nucleus enters egg, cortical granules fuse with membrane
List and describe the function of the 4 extraembryonic membranes associated with an amniotic egg. What function does each of the 4 extraembryonic membranes serve in mammals. (what do they develop into)
Chorion completely surrounds the embryo and other embryonic membranes, functions in gas exchange and grows into the fetal side of the placenta in mammals. Amnion encloses the embryo in a fluid filled amniotic cavity, insulates/cushions/protects developing embryo and prevents dessication of the embryo. Yolk sac is found below the developing embryo and contains nutrients for developing embryo and is the site of 1st blood cell formation in mammals. Allantois develops as an outpocketing of the embryo's rudimentary gut, stores N-waste produced by embryo, and develops into the umbilical cord in mammals.
Distinguish between the terms: conception, gestation & parturition.
Conception is when the sperm fertilizes an egg. Gestation is the process of the development of the embryo/fetus inside the mother. Parturition is the birth of the child.
What is contraception? List 10 types of contraceptive techniques outlined by your text.
Contraception is preventing the sperm and egg from joining. Condom, Sponge, Spermicides, Vaginal Ring, Injection, Implant, Natural Family Planning, Withdrawal, Sterilization, Cervical Cap
What is the function of Estrogen in the female? Progesterone?
Estrogen causes endometrium thickening and development of secondary sex characteristics. Progesterone causes and maintains endometrium thickening.
What is the function of FSH in the female? LH?
FSH stimulates follicle and oocyte development in ovary. LH causes follicle to mature and break open.
What is the function of FSH in the male? LH?
FSH stimulates sperm production. LH stimulates testes to produce testosterone.
What is the function of GNRH?
GNRH is the key regulator of the reproductive axis, it causes the pituitary gland to make and secrete LH and FSH.
What are the hormones associated with female reproduction? Where are these hormones produced and What are the functions of each? (Outline the hormonal control in the female)
Releasing hormone is produced in the hypothalamus and stimulates anterior pituitary. Follicle stimulating hormone is produced in the anterior pituitary and stimulates follicle and oocyte development in the ovary. Luteinizing hormone is produced in the anterior pituitary and causes the follicle to mature and break open. Estrogen is produced in the follicle and corpus luteum and causes endometrium thickening and the development of secondary sex characteristics. Progesterone is produced in the corpus luteum and causes and maintains endometrium thickening.
What are the male reproductive organs/structures and what is the function of each.
Scrotum contains/holds teste and thermoregulates teste. Penis is the male copulatory organ, it empties urea from excretory tract and semen from reproductive tract. Testes are the site of sperm cell production and the site of male hormone production. Epididymis are the coiled tubules that receive spermatids and is the site of maturation of spermatids to sperm. Vas Deferens is the sit of sperm storage until ejaculation. Ejaculatory Duct is the intersection region of the 2 VD tubes. Urethra is the tube exiting the penis that empties excretory and reproductive tracts.
What is spermatogenesis? Where does it occur? Describe the process.
Spermatogenesis is sperm cell production. It occurs in the wall of the seminiferous tubules. The diploid cells, called spermatogonia, go through mitosis with one offspring going on to differentiate into a sperm cell and the other giving rise to the next generation of sperm.
Trace the pathway of sperm through the male reproductive system, from site of production to ejaculation.
Testes, epididymis, Vas Deferens, Seminal vesicle, Ejaculatory duct, prostate, urethra
What is the function of Testosterone?
Testosterone stimulates sperm production and the development of secondary sex characteristics.
Why are the ovarian and uterine cycles linked by hormonal control?
The different hormones in the female body trigger reactions in the cycles. For example, in the ovarian cycle, the follicle increases its secretion of estrogen and this hormone triggers the cells of the uterine lining to proliferate and the lining becomes thicker.
List the 3 embryonic germ layers in vertebrates and the major organ/systems that develop from each germ layer.
The ectoderm is the outer layer of embryo, develops epidermis and sweat glands, nervous and sensory systems, pituitary gland, adernal medulla, jaws and teeth, germ cells. The mesoderm is the middle layer of embryo, develops skeletal, muscular, circulatory, lymphatic, excretory, reproductive systems, dermis, adrenal cortex. The endoderm is the inner layer, develops epithilial lining of digestive tract and associated organs, epithilial lining of respiratory, excretory, and reproductive tracts and ducts, thymus, thyroid and parathyroid glands.
Describe the process and products/results of the Ovarian Cycles' Follicular Phase to its Luteal Phase.
The follicular phase is when the follicle inside the ovary grows and matures. The follucle produces increasing amounts of Estrogen. Meiosis I completes inside follicle resulting in the production of a secondary oocyte. The luteal phase is when the empty follucle tissue becomes the corpus luteum. The corpus luteum degenerates and produces decreasing amounts of progesterone and the dropping progesterone levels trigger the uterine cycle to begin.
List the 3 accessory glands associated with male reproduction. Where are these products released into the reproductive system?
The seminal vesicles are a pair of glands located behind/below the bladder. It produces 60% of ejaculate, including mucous that functions in sperm protection, fructose that functions in sperm energy, prostaglandins that stimulate uterine contractions, and amino acids that coagulate semen. It empties into the ejaculatory duct. The prostate gland is a single gland that produces alkaline fluid that neutralizes the acidity of the male and female reproductive tracts. It empties into the urethra. The Bulbourethral glands are a pair of glands that produce a viscous fluid and empties into the urethra.
List & draw the stages included in embryological development (in order of occurrence)
Zygote, 2 cell, 4 cell, 8 cell, 16 cell, morula, blastula, gastrula, neurula
What is the function of GNRH?
causes the pituitary gland to make and secrete LH abd FSH as well as estrogen and progesterone.
Blastulation-
creation of a blastula stage embryo, creates a hollow cavity called a blastocoel, cells in center of morula stage move to outside edge of embryo
Neurulation-
forms the organs from the three embryonic germ layers, first major event of organogenesis
Cleavage-
rapid cell division following fertilization, occurs in the oviduct, partitions the zygote into many smaller cells
Gastrulation-
rearrangement of cells of the blastula stage to form a three layered embryo with a primitive gut, and one side of the blastula embryo invaginates into blastocoel and forms a new cavity called an archenteron