SUBSCRIBE
BIOS 225 Final Exam 3
- Describe the structure and function of the human female reproductive sys- tems including the
- Describe the structure and function of the human female reproductive sys- tems including the
names of the cells/processes involved in ovum production. FORMATION OF OVUM –Answer Early germ cells in the ovary called OOGONIA, increase in number by mitosis and is a diploid cell. Eventually they grow in size and become PRIMARY OOCYTES. Before the first meiotic division, chromosomes in each pri- mary oocyte meet in pairs, paternal and maternal homologues. With first division, the cytoplasm is divided unequally. One of the two daughter cells is a SECONDARY OOCYTE and the other is called a FIRST POLAR BODY; although different in size, each receive half the chromosomes. In second meiotic division, the secondary oocyte divides into a large OOTID and a smaller polar body. If the first polar body divides, then you result with three polar bodies and one ootid. The ootid develops into a functional, haploid OVUM. Polar bodies are non functional and disintegrate, it is necessary to form them to dispose to excess chromosomes.*One mature ovum has N(haploid) number of chromosomes, the same as a sperm.However, each primary oocyte gives rise to only one functional gamete, whereas it produces four gametes in spermatogenesis ** in humans, meiosis two is completed only when the secondary oocyte is pene- trated by a spermatozoon.
names of the cells/processes involved in ovum production. STRUCTURES OF FEMALE
REPRODUCTIVE SYSTEMS
–Answer OVARIES produce both ovum and female sex hormones- estrogens and progesterone. Mature ova from each ovary enter the funnel-like opening of an OVIDUCT (fallopian tube) which has a fringed margin that envelops the ovary at the time of ovulation. The end of the oviduct expands into a muscular UTERUS in which embryos complete their development. Each oocyte develops within follicle that enlarges and finally ruptures to release a secondary oocyte. During female fertile years approximately 13 oocytes mature each year; because women are only fertile 30 years, only 300ish out of 400,000 primary oocytes have the chance to reach maturity. The OVIDUCTS have cilia for propelling the egg away from ovary. The two ducts open to the corners of the UTERUS or womb which is specialized for housing embryo. It has thick muscular walls, many blood vessels, and a specialized lining –Answer ENDOMETRIUM. The VAGINA is a muscular tube adapted to receive the male's penis and 1 / 3
SUBSCRIBE
serves as the birth canal for expulsion of the baby from uterus. Where vagina and uterus meet is the CERVIX. The external genitalia of human females, or VULVA, include folds of the skin- LABIA MAJORA and LABIA MINORA, and a small erectile organ, the CLITORIS( the female homolog of the glans penis of males). In a virgin state, the opening into a vagina is smaller if the membrane HYMEN is still in tact, but due to more physically active females, the membrane may be reduced.
- Describe the structure and function of the human male reproductive sys- tems including
the names of the cells/processes involved in spermatozoa production.
FORMATION OF SPERM
–Answer Walls of seminiferous tubules contain different germ cells in a stratified layer of 5 to 8 cells deep.Germ cells develop in close contact with sertoli cells which provide nourishment during germ cell development.-the outermost layer contain spermatogonia, diploid cells which have increased in number by mitosis -each spermatogonia increases in size and becomes primary spermatocyte -primary spermatocyte undergoes first meiotic division and becomes two secondary spermatocytes -each secondary spermatocyte enters second meiotic division and produces two spermatids, each containing haploid number (23 chromosomes) -without further division the spermatids transform into mature spermatozoa (sperm) SPERM –Answer
acrosome -projects suddenly from the sperm head when first contacts surface of the egg nucleus- in head of sperm midpiece- mitochondria
- Describe the structure and function of the human male reproductive sys- tems including
the names of the cells/processes involved in spermatozoa production.
STRUCTURES OF MALE REPRODUCTIVE SYSTEMS
–Answer Paired TESTES are the sites of sperm production, each testis is composed of numerous SEMINIFEROUS TUBULES, where the sperm develop. The sperm are surrounded by SERTOLI CELLS which nourish the 2 / 3
SUBSCRIBE
developing sperm. Between tubules are INTERSTITIAL CELLS (or leydig cells) which produce the male hormone TESTOSTERONE. Two testes are housed in a saclike scrotum suspended outside abdominal cavity; so that sperm can form in the cooler temperatures 'outside' the body. The sperm travel from SEMINIFEROUS TUBULES to the VASA EFFERENTIA, small tubes connected to a coiled EPIDIDYMIS, where final sperm maturation occurs and then to a VAS DEFERENS the ejaculatory duct. The vas deferens joins the URETHRA, a duct that carries both sperm and urinary products through the PENIS, or external intromittent organ.
GLANDS
–Answer a pair of seminal vesicles (fructose), a single prostate gland-valve to semen/urine , and a pair of bulbourethral glands (alkaline mucus); fluid is secreted by these glands feeds sperm, lubricates female reproductive tact for sperm, and counteracts the acidity of the vagina so that the sperm are viable longer
- Where do ertilization and implantation occur in humans?
- Outline the hormonal control of female menstrual cycle; explain how preg- nancy changes
- / 3
–Answer fertilization –Answer in the Fallopian tubes implantation –Answer in the endometrium of the uterus
this pattern (i.e. you should be able to explain the graphs associated with the menstrual cycle (hormones, what's happening in the ovary and uterus) as well as the graph associated with the scenario when the secondary oocyte is fertilized (hormones and where they come from and what they do).–Answer estrogen and progesterone prepare uterus to receive developing embyro. These hormones are controlled by anterior pituitary gonadotropins –Answer FSH and LH; the release of these two gonadotropins is in turn governed by GnRH (gonadotropin-releasing hormone) which is produced by hypothalamus.FSH- primarily stimulates follicle growth LH- stimulates ovulation