Ch.17: Reproductive System
Female gonads
(ovaries) produce oocytes (eggs)
Male gonads
(testes) produce sprem
Menstrual cycle
- follicular pase - ovulation - luteal phase - menstruation
Menstruation
- if the ovum is not fertilized, the corpus luteum degrades, result in decrease of estrogen and progesterone levels, which cause the endometrium to slough off, giving rise to the menstrual flow (menses) - if fertilization occurs, the developing placenta produces hCG (human chorionic gonadotropin), maintaining the corpus luteum as well as the supply of estrogen and progesterone that maintains the uterus. Eventually the placenta will take over production of these hormones
Progesterone
- steroid hormone secreted by the corpus luteum during luteal phrase of the menstrual cycle - stimulates the development and maintenance of the endometrium in preparation for implantation https://classconnection.s3.amazonaws.com/875/flashcards/1191875/jpg/femrep1335122672747.jpg
Estrogen
- steroid hormones necessary for normal female maturation - stimulate the development of the female reproductive tract, contribute to the development of secondary sexual characteristics, and influence libido - responsible for the thickening of the endometrium (the inner lining of the uterine wall) - secreted by the ovarian follicles and the corpus luteum
The production of functional sex cells is called___________
Gametogenesis
The gametes are produced in specialized organs called_____
Gonads
Egg production (female)
Oogenesis
Sperm production (male)
Spermatogenesis
Other than sperm, testes also produce_________
Testosterone
Female Sex Hormones
The ovaries synthesize and secrete female sex hormones, including estrogens and progesterone. The secretion of both estrogens and progesterone is regulated by luteinizing hormone (LH) and follicle stimulating hormone (FSH), which are regulated by gonadotripin-releasing hormone (GnRH)
Follicular phase
begins when the previous menstrual flow stop; during this phase, FSH from the anterior pituitary promotes the development of the follicle, which grows and begins secreting estrogen
Fertilization
egg and sperm combine to form zygote with diploid number of chromosomes - an egg can be fertilized during the 12-24 hr after ovulation - occurs in the lateral, widest part of the fallopian tube
Ovaries
found in abdominal cavity below digestive system; consist of thousands of follicles
Dizygotic twins
fraternal twins, result when 2 ova are released in one ovarian cycle and are fertilized by 2 different sperm. Share no more characteristics than any other siblings since they develop from 2 distinct zygotes
Sexual reproduction
genetic material of 2 organisms combines and results in genetically unique offspring Required: - functional sex cells or gametes by adult organisms - fertilization or conjugation to form zygote - development of zygote into another adult, completing the cycle
Monozygotic twins
identical twins, result when a single zygote splits into 2 embryos. Occasionally the division is incomplete, resulting in the birth of "Siamese" (conjoined) twins, which are attached at some point on the body and often share limbs and organs. Genetically identical twins
Ovum to sperm route (sperm actually travel to ovum in reverse order)
immature ovum released from ovary into abdominal cavity and drawn by cilia into the nearby oviduct (fallopian tube) --> uterus --> cervix --> vaginal canal - sperm remain viable for 1-2 days after intercourse
Follicle
multilayered sac of cells that contains nourishes and protects immature ovum; also produce estrogen
Luteal phase
occurs after ovulation, LH maintains fraction of the ruptured follicle (corpus luteum), which secretes estrogen and progesterone - Progesterone causes the glands of the endometrium to mature and produce secretions that prepare it for the implantation of an embryo - Progesterone and estrogen are essential for the maintenance of the endometrium
Ovulation
occurs midway through the cycle; a mature ovarian follicle bursts and release an ovum. Ovulation caused by a surge (increase) in LH that is produced, and in part caused by a peak in estrogen levels
Hermaphrodites
organisms that contain both male and female gonads (i.e. hydra and earthworm)
Internal fertilization
practice by terrestrial vertebrates and provides direct route for sperm to reach egg cell; thus, increase the chance of fertilization success and female produce fewer eggs. (species that care for their young produce fewer eggs)
Testosterone
regulates secondary male sex characteristics including facial and pubic hair, and voice changes
Testes are located in_______
scrotum - an external punch near penis that maintains testes' temp at 2-4C lower than body temp, which creates a condition where sperm can survive
Uterus
site of fetal development
Sperm route
sperm pass from testes --> vas deferens --> ejaculatory duct --> urethra --> penis --> glans of penis (see pg. 192)