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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
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