Animal development Flashcards
parthenogenesis
asexual reproduction in which an egg develops without being fertilized
ovaries
female gonads; contains follicles which contains eggs
follicle
in the ovary; consists of one egg cell surrounded by one or more layers of follicle cells
oviduct
egg cell is realeased into this tube and travels to uterus
testes
male gonads; sperm forms in seminiferous tubules inside testes
epididymis
tubules where sperm passes and pushed through vas deferens duct
urethra
duct that drains both excretory and reproductive system
oogenesis
secondary oocyte can become the ovum; other 3 products of meiosis becomes polar bodies
FSH
follicle stimulating hormone; induces primary oocyte to undergo meiosis to metaphase II
ovulation
secondary oocyte is released at metaphase II and stays until sperm penetrates oocyte
menstrual cycle
endometrium increases with progesterone and estrogen release
estrous sycle
endometrium is reabsorbed without bleeding and animals are in heat
organogenesis
first trimester is main period of body organ development
acrosome
specialized vesicle at the tip of the sperm discharges hydrolytic enzymes which penetrates the jelly coat of egg
acrosomal process
actin filaments grow from sperm and contact egg cell receptors on vitelline layer
polyspermy fast block
fusion of sperm and egg membrane causes depolarization and produces fast block to multiple sperm entry
cortical reaction
slow block to polyspermy; fertilization envelope from cortical granules and hardening of vitelline layer
zona pellucida
in mammals this is hardened during cortical reaction
morula
first 5-7 divisions for a multicellular ball surrounded by fertilization envelope
blastula
avian; at least 128 cells with blastocoel in animal pole and yolk in vegetal pole
meroblastic cleavage
incomplete cleavage of yolk and embryo in avian egg
avian epiblast/hypoblast
avian version of a blastula and surrounds the blastocoel
gastrula
three germ layers of the embryo
archenteron
invagination at the blastopore; is the primitive gut with 2 openings
epiblast
all the cells that will form the embryo come from this layer
primitive streak
cells from epiblast form each of the 3 germ layers
notochord
formed from dorsal mesodermthat condenses just above the archenteron and is present in all chrodates
neural tube
from ectoderm; becomes central nervous system; rolled in from neural plate
neural crest
only vertebrates; forms peripheral nerves, teeth, skull bones, and other cells
holoblastic cleavage
mammals and others such as sea urchins; complete division of eggs having little yolk or moderate such as frogs
ectoderm
epidermis of skin, epithelium of mouth/rectum, cornea, nervous system
mesoderm
notochord, skeletal, muscular, excretory, circulatory, and reproductive system, lining of body cavity
endoderm
epithelial of digestive, excretory, reproductive, and respiratory system, pancreas, liver, thymus
blasctocyst
mammalian version of the blastula with an inner cell mass that becomes embryo and most of extraembryonic
trophoblast
outer layer of the blastocyst that initiates endometrium implantation
mammalian epiblast
similar to avian, embryo almost entirely develops from epiblast cells
chorion
completely surrounds embryo and other extraembryonic membranes and functions gas exchange
allantois
incorporated into the umbilical cord and forms blood vessels with placenta
cadherins
class of cell adhesion molecule that requires calcium ions for proper function
