Biology Review and Vocabulary Part 14

abortion-The termination of a pregnancy in progress.

asexual reproduction-A type of reproduction involving only one parent that produces genetically identical offspring by budding or by the division of a single cell or the entire organism into two or more parts.

assisted reproductive technology-Fertilization procedures that generally involve the surgical removal of eggs (secondary oocytes) from a woman’s ovaries following hormonal stimulation, fertilizing the eggs, and returning them to the woman’s body.

baculum-A bone that is contained in, and helps stiffen, the penis of rodents, raccoons, walruses, whales, and several other mammals.

barrier methods-Contraception that relies on a physical barrier to block the passage of sperm. Examples include condoms and diaphragms.

bartholins gland-Glands near the vaginal opening in a human female that secrete lubricating fluid during sexual arousal.

birth control pill-Chemical contraceptives that inhibit ovulation, retard follicular development, or alter a woman’s cervical mucus to prevent sperm from entering the uterus.

blastocyst-An embryonic stage in mammals; a hollow ball of cells produced one week after fertilization in humans.

budding-An asexual means of propagation in which outgrowths from the parent form and pinch off to live independently or else remain attached to eventually form extensive colonies.

bulbourethral glands-One of a pair of glands near the base of the penis in the human male that secretes fluid that lubricates and neutralizes acids in the urethra during sexual arousal.

cervix-The neck of the uterus, which opens into the vagina.

cleavage-The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically, the succession of rapid cell divisions without growth during early embryonic development that converts the zygote into a ball of cells.

clitoris -An organ in the female that engorges with blood and becomes erect during sexual arousal.

cloaca-A common opening for the digestive, urinary, and reproductive tracts found in many nonmammalian vertebrates but in few mammals.

coitus-The insertion of a penis into a vagina, also called sexual intercourse.

conception-The fertilization of the egg by a sperm cell in humans.

condom-A thin, latex rubber or natural membrane sheath that fits over the penis to collect semen.

contraception-The prevention of pregnancy.

corpus luteum-A secreting tissue in the ovary that forms from the collapsed follicle after ovulation and produces progesterone.

diaphragm-(1) A sheet of muscle that forms the bottom wall of the thoracic cavity in mammals; active in ventilating the lungs. (2) A dome-shaped rubber cup fitted into the upper portion of the vagina before sexual intercourse. It serves as a physical barrier to block the passage of sperm.

ejaculation-The propulsion of sperm from the epididymis through the muscular vas deferens, ejaculatory duct, and urethra.

ejaculatory duct-The short section of the ejaculatory route in mammals formed by the convergence of the vas deferens and a duct from the seminal vesicle. The ejaculatory duct transports sperm from the vas deferens to the urethra.

endometrium-The inner lining of the uterus, which is richly supplied with blood vessels.

epididymus-A coiled tubule located adjacent to the testes where sperm are stored.

estrous cycles -A type of reproductive cycle in all female mammals except higher primates, in which the nonpregnant endometrium is reabsorbed rather than shed, and sexual response occurs only during mid-cycle at estrus.

estrus-A period of sexual activity associated with ovulation.

external fertilization-The fusion of gametes that parents have discharged into the environment.

fetilization-The union of haploid gametes to produce a diploid zygote.

fetus-A developing human from the ninth week of gestation until birth; has all the major structures of an adult.

follicle-A microscopic structure in the ovary that contains the developing ovum and secretes estrogens.

follicular cycle-

fragmentation-A means of asexual reproduction whereby a single parent breaks into parts that regenerate into whole new individuals.

gametes-A haploid cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.

gametogenesis-The process by which gametes are produced in the mammalian body.

gestation-Pregnancy; the state of carrying developing young within the female reproductive tract.

glans penis-The head end of the penis.

gonads-The male and female sex organs; the gamete-producing organs in most animals.

hermaphroditism -A condition in which an individual has both female and male gonads and functions as both a male and female in sexual reproduction by producing both sperm and eggs.

human chorionic gonadotropin-A hormone secreted by the chorion that maintains the corpus luteum of the ovary during the first three months of pregnancy.

hymen-A thin membrane that partly covers the vaginal opening in the human female. The hymen is ruptured by sexual intercourse or other vigorous activity.

internal fertilization -Reproduction in which sperm are typically deposited in or near the female reproductive tract and fertilization occurs within the tract.

in vitro fertilization -Fertilization of ova in laboratory containers followed by artificial implantation of the early embryo in the mother’s uterus.

labia majora-A pair of thick, fatty ridges that enclose and protect the labia minor and vestibule.

labia minora-A pair of slender skin folds that enclose and protect the vestibule.

labor-A series of strong, rhythmic contractions of the uterus that expel a baby out of the uterus and vagina during childbirth.

leydig cells-A cell that produces testosterone and other androgens and is located between the seminiferous tubules of the testes.

luteal phase-That portion of the ovarian cycle during which endocrine cells of the corpus luteum secrete female hormones.

menopause-The cessation of ovulation and menstruation.

menstrual cycle-A type of reproductive cycle in higher female primates, in which the nonpregnant endometrium is shed as a bloody discharge through the cervix into the vagina.

menstruation-The shedding of portions of the endometrium during a uterine (menstrual) cycle.

menustral flow phase-The shedding of portions of the endometrium during a uterine (menstrual) cycle.

mytonia-Increased muscle tension.

natural family planning-A form of contraception that relies on refraining from sexual intercourse when conception is most likely to occur; also called the rhythm method.

oogenesis-The process in the ovary that results in the production of female gametes.

organogenesis-The development of organ rudiments from the three germ layers.

orgasm-Rhythmic, involuntary contractions of certain reproductive structures in both sexes during the human sexual response cycle.

ovarian cycle-The cyclic recurrence of the follicular phase, ovulation, and the luteal phase in the mammalian ovary, regulated by hormones.

ovaries-(1) In flowers, the portion of a carpel in which the egg-containing ovules develop. (2) In animals, the structure that produces female gametes and reproductive hormones.

oviduct-A tube passing from the ovary to the vagina in invertebrates or to the uterus in vertebrates.

ovulation-The release of an egg from ovaries. In humans, an ovarian follicle releases an egg during each uterine (menstrual) cycle.

parthogenesis-A type of reproduction in which females produce offspring from unfertilized eggs.

parturition-The expulsion of a baby from the mother; also called birth.

penis-The copulatory structure of male mammals.

pheromones-In animals and fungi, a small, volatile chemical that functions in communication and that in animals acts much like a hormone in influencing physiology and behavior.

placenta-A structure in the pregnant uterus for nourishing a viviparous fetus with the mother’s blood supply; formed from the uterine lining and embryonic membranes.

pregancy-The condition of carrying one or more embryos in the uterus.

prepuce-A fold of skin covering the head of the clitoris and penis.

proliferative phase-That portion of the uterine (menstrual) cycle when the endometrium regenerates and thiA gland in human males that secretes an acid-neutralizing component of semen. ckens.

prostate gland-A gland in human males that secretes an acid-neutralizing component of semen.

regeneration-The regrowth of body parts from pieces of an organism.

rhythm method-A form of contraception that relies on refraining from sexual intercourse when conception is most likely to occur; also called natural family planning.

scrotum-A pouch of skin outside the abdomen that houses a testis; functions in cooling sperm, thereby keeping them viable.

secretory phase-That portion of the uterine (menstrual) cycle when the endometrium continues to thicken, becomes more vascularized, and develops glands that secrete a fluid rich in glycogen.

semen-The fluid that is ejaculated by the male during orgasm; contains sperm and secretions from several glands of the male reproductive tract.

seminal vesicles-A gland in males that secretes a fluid component of semen that lubricates and nourishes sperm.

seminiferous tubules- A gland in males that secretes a fluid component of semen that lubricates and nourishes sperm. A highly coiled tube in the testis in which sperm are produced.

sequential hermaphroditism-A reproductive pattern in which an individual reverses its sex during its lifetime.

sexual reproduction -A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from the gametes of the two parents.

spermatheca-A sac in the female reproductive system where sperm are stored.

spermatogenesis-The continuous and prolific production of mature sperm cells in the testis.

testes-(plural, testes) The male reproductive organ, or gonad, in which sperm and reproductive hormones are produced.

trimesters-In human development, one of three 3 month-long periods of pregnancy.

trophoblast-The outer epithelium of the blastocyst, which forms the fetal part of the placenta.

tubal ligation-A means of sterilization in which a woman’s two oviducts (Fallopian tubes) are tied closed to prevent eggs from reaching the uterus. A segment of each oviduct is removed.

urethra-A tube that releases urine from the body near the vagina in females and through the penis in males; also serves in males as the exit tube for the reproductive system.

uterine cycle-The changes that occur in the uterus during the reproductive cycle of the human female; also called the menstrual cycle.

uterus-A female organ where eggs are fertilized and/or development of the young occurs.

vagina-Part of the female reproductive system between the uterus and the outside opening; the birth canal in mammals; also accommodates the male’s penis and receives sperm during copulation.

vas deferens-The tube in the male reproductive system in which sperm travel from the epididymis to the urethra.

vasectomy-The cutting of each vas deferens to prevent sperm from entering the urethra.

vasocongestion-The filling of a tissue with blood, caused by increased blood flow through the arteries of that tissue.

vestibule-The cavity enclosed by the labia minora; the space into which the vagina and urethral opening empty.

vulva-Collective term for the female external genetalia.

zygote-The diploid product of the union of haploid gametes in conception; a fertilized egg.