- acrosomal reaction
- series of biochemical reactions that the sperm uses to break through the zona pellucida
- amniote
- an organism whose embryo develops within a shelled egg with extraembryonic membranes
- asexual reproduction
- form of reproduction that produces offspring that are genetically identical to the parent
- blastocyst
- structure formed when cells in the mammalian blastula separate into an inner and outer layer
- budding
- form of asexual reproduction that results from the outgrowth of a part of a cell leading to a separation from the original animal into two individuals
- bulbourethral gland
- secretion that cleanses the urethra prior to ejaculation
- clitoris
- sensory structure in females; stimulated during sexual arousal
- cloaca
- common body opening for the digestive, excretory, and reproductive systems found in non-mammals, such as birds
- contraception
- (also, birth control) various means used to prevent pregnancy
- estradiol
- most potent form of estrogen that is responsible for the development of female secondary female characteristics, maintenance of female reproductive organs, and preparation for pregnancy
- estrogen
- reproductive hormone in females that assists in endometrial regrowth, ovulation, and calcium absorption
- external fertilization
- fertilization of egg by sperm outside animal body, often during spawning
- fission
- (also, binary fission) method by which multicellular organisms increase in size or asexual reproduction in which a unicellular organism splits into two separate organisms by mitosis
- follicle stimulating hormone (FSH)
- reproductive hormone that causes sperm production in men and follicle development in women
- fragmentation
- cutting or fragmenting of the original animal into parts and the growth of a separate animal from each part
- gastrulation
- process in which the blastula folds over itself to form the three germ layers
- gestation
- length of time for fetal development to birth
- gonadotropin-releasing hormone (GnRH)
- hormone from the hypothalamus that causes the release of FSH and LH from the anterior pituitary
- hermaphroditism
- state of having both male and female reproductive parts within the same individual
- holoblastic
- complete cleavage; takes place in cells with a small amount of yolk
- human beta chorionic gonadotropin (β-HCG)
- hormone produced by the chorion of the zygote that helps to maintain the corpus luteum and elevated levels of progesterone
- infertility
- inability to conceive, carry, and deliver children
- inhibin
- hormone made by Sertoli cells; provides negative feedback to hypothalamus in control of FSH and GnRH release
- inner cell mass
- inner layer of cells in the blastocyst
- internal fertilization
- fertilization of egg by sperm inside the body of the female
- interstitial cell of Leydig
- cell in seminiferous tubules that makes testosterone
- labia majora
- large folds of tissue covering the inguinal area
- labia minora
- smaller folds of tissue within the labia majora
- luteinizing hormone (LH)
- reproductive hormone in both men and women, causes testosterone production in men and ovulation and lactation in women
- menopause
- loss of reproductive capacity in women due to decreased sensitivity of the ovaries to FSH and LH
- menstrual cycle
- cycle of the degradation and re-growth of the endometrium
- meroblastic
- partial cleavage; takes place in cells with a large amount of yolk
- morning sickness
- condition in the mother during the first trimester; includes feelings of nausea
- neural tube
- tube-like structure that forms from the ectoderm and gives rise to the brain and spinal cord
- oogenesis
- process of producing haploid eggs
- organogenesis
- process of organ formation
- ovarian cycle
- cycle of preparation of egg for ovulation and the conversion of the follicle to the corpus luteum
- oviduct
- (also, fallopian tube) muscular tube connecting the uterus with the ovary area
- oviparity
- process by which fertilized eggs are laid outside the female’s body and develop there, receiving nourishment from the yolk that is a part of the egg
- ovoviparity
- process by which fertilized eggs are retained within the female; the embryo obtains its nourishment from the egg’s yolk and the young are fully developed when they are hatched
- ovulation
- release of the egg by the most mature follicle
- parthenogenesis
- form of asexual reproduction where an egg develops into a complete individual without being fertilized
- penis
- male reproductive structure for urine elimination and copulation
- placenta
- organ that supports the diffusion of nutrients and waste between the mother’s and fetus’ blood
- polyspermy
- condition in which one egg is fertilized by multiple sperm
- progesterone
- reproductive hormone in women; assists in endometrial re-growth and inhibition of FSH and LH release
- prostate gland
- structure that is a mixture of smooth muscle and glandular material and that contributes to semen
- scrotum
- sac containing testes; exterior to the body
- semen
- fluid mixture of sperm and supporting materials
- seminal vesicle
- secretory accessory gland in males; contributes to semen
- seminiferous tubule
- site of sperm production in testes
- Sertoli cell
- cell in seminiferous tubules that assists developing sperm and makes inhibin
- sexual reproduction
- mixing of genetic material from two individuals to produce genetically unique offspring
- somite
- group of cells separated by small spaces that form from the mesoderm and give rise to connective tissue
- spermatheca
- specialized sac that stores sperm for later use
- spermatogenesis
- process of producing haploid sperm
- testes
- pair of reproductive organs in males
- testosterone
- reproductive hormone in men that assists in sperm production and promoting secondary sexual characteristics
- trophoblast
- outer layer of cells in the blastocyst
- uterus
- environment for developing embryo and fetus
- vagina
- muscular tube for the passage of menstrual flow, copulation, and birth of offspring
- viviparity
- process in which the young develop within the female, receiving nourishment from the mother’s blood through a placenta
- zona pellucida
- protective layer of glycoproteins on the mammalian egg