Flashcards in Reproductive System Deck (49):
What does sexual reproduction require?
-Production of functional gametes
-Fertilization forms zygote
-Zygote -- adult
Where are gametes produced?
-Gonads (testes in seminiferous tubules and ovaries produce oocytes-eggs)
Which species include hermaphrodites?
-Hydra and earthworm
What is gametogenesis called in males? Females?
Internal fertilization is practiced by...
Do females produce more or less eggs in external fertilization?
-Less chance for fertilization
What other factors decrease amount of eggs produced?
-Species cares for young
-Development occurs inside mother's body
Where are the testes located?
Trace the path of sperm.
Testes --> vas deferens --> ejaculatory duct --> urethra --> glans
What systems is the urethra involved in for men?
-Reproductive and excretory
Where is testosterone produced?
Where does spermatogenesis occur?
Diploid spermatogonia differentiate into diploid primary spermatocytes --> meiosis --> haploid secondary spermatocytes --> meiosis --> 4 haploid spermatids --> spermatozoa (mature sperm)
What is in the head of the sperm?
What is in the neck/body of the sperm?
What is the acrosome?
-Caplike structure derived from GOlgi that develops over the anterior half of head
-Contains enzymes needed to penetrate ovum
What are follicles in the ovaries?
-Multilayered sacs of cells that contain, nourish, protect the immature ovum
Follow the path of an immature ovum.
Released from ovary --> abdominal cavity --> drawn by cilia into oviduct (fallopian tube) --> uterus --> cervix
Where does fetal fevelopment occur?
What is the narrow end of the uterus called?
Where does oogenesis occur?
When have most of the immature ova (primary oocytes) formed?
-At birth of female
What are primary oocytes?
-Diploid cells formed by mitosis that will be released once a month to complete meiosis I
What forms after meiosis I of primary oocyte?
-One secondary oocyte and a small polar body
What occurs to the secondary oocyte?
-Expelled from follicle during ovulation and undergoes meiosis II after fertilization triggered by one of the layers being penetrated
What are the two layers that surround the oocyte cell membrane?
-Inner zone pellucida layer
-Outer corona radiata layer
What forms from meiosis II of secondary oocyte?
-Mature ovum and another polar body
-Mature ovum contains cytoplasm, RNA, organelles, nutrients for embryo
Where are female sex hormones produced?
-Estrogen, progesterone secretion regulated by LH and FSH which is regulated by GnRH
-Stimulate development of female reproductive tract
-Secondary sex traits
-Thickening of endometrium (inner lining of uterine wall)
-Secreted by ovarian follicles and corpus luteum
-Corpus luteum secretes during luteal phase
-Dev/maintenance of endometrium prepare for implantation
What are the phases of the menstrual cycle?
Follicular phase --> Ovulation --> Luteal phase --> Menstruation (-->Fertilization does not occur)
-Cessation of menstrual flow from previous cycle
-FSH --> dev follicles --> secrete estrogen
-Mature ovarian follicle bursts --> ovum
-Caused by surge in LH, preceded by peak estrogen
When does ovulation not occur?
-Pregnancy, lactation, menopause
What occurs in menopause?
-Ovaries less sensitive to FSH and LH and atrophy
What occurs during luteal phase?
-LH maintains corpus luteum
What occurs during menstruation?
-Corpus luteum atrophies
-Progesterone/Estrogen decrease --> endometrium slough off
What does the developing placenta produce to maintain the corpus luteum and progersterone/estrogen?
-hCG (human chorionic gonadotropic)
When can the egg be fertilized?
12-24 hrs after ovulation at lateral/widest portion of fallopian tube
How many days does sperm remain viable?
1-2 days after intercourse
What is the course the sperm travels to fertilize egg?
Vaginal canal --> Cervix --> Uterus --> Fallopian tubes --> ovum
What is the first barrier the sperm must penetrate?
-Corona radiata then zona pellucida (acrosome enzymes)
What occurs when sperm makes contact with the ovum membrane?
-Form tube-like structure (acrosomal process) to fuse allowing sperm nucleus to enter ovum's cytoplasm
When does the ovum complete meiosis II?
-When sperm enters ovum's cytoplasm
What is the cortical reaction resulting from acrosomal process?
-Ca++ released to cytoplasm --> form fertilization membrane and increases metabolic rate of ovum
What is the fertilization membrane?
-Hard layer surrounding ovum cell membrane to prevent multiple fertilizations
What is the difference between monozygotic and dizygotic twins?
-Mono is single zygote splitting into two embryos (identical)
-Di is two ova released and fertilized by diff sperm (fraternal)
At which stage of splitting will the embryo have separate chorions/placentas?
-At blastula stage, embryos have one chorionic sac and one placenta/possibly one amnion