|[[Cardiovascular System Development|Cardiovascular Terms]]|
|Cardiovascular System Development For more cardiovascular term definitions and links to related topics use the glossary.
angioblast - the stem cells in blood islands generating endothelial cells which will form the walls of both arteries and veins. (More? Blood Vessel)
angiogenesis - the formation of blood vessels also called vasculogenesis in the embryo.
anlage (German, anlage = primordium) structure or cells which will form a future more developed or differentiated adult structure.
blood islands - earliest sites of blood vessel and blood cell formation, seen mainly on yolk sac chorion.
cardinal veins - paired main systemic veins of early embryo, anterior, common, posterior.
cardiogenic region - region above prechordal plate in mesoderm where heart tube initially forms.
ectoderm - the layer (of the 3 germ cell layers) which form the nervous system from the neural tube and neural crest and also generates the epithelia covering the embryo.
endoderm - the layer (of the 3 germ cell layers) which form the epithelial lining of the gastrointestinal tract (GIT) and accessory organs of GIT in the embryo.
endocardium - lines the heart. Epithelial tissue lining the inner surface of heart chambers and valves.
endothelial cells - single layer of cells closest to lumen that line blood vessels.
extraembryonic mesoderm - mesoderm lying outside the trilaminar embryonic disc covering the yolk sac, lining the chorionic sac and forming the connecting stalk. Contributes to placental villi development.
haemocytoblasts - stem cells for embryonic blood cell formation.
anastomose - to connect or join by a connection (anastomosis) between tubular structures.
chorionic villi - the finger-like extensions which are the functional region of the placental barrier and maternal/fetal exchange. Develop from week 2 onward as: primary, secondary, tertiary villi.
estrogens - support the maternal endometrium.
growth factor - usually a protein or peptide that will bind a cell membrane receptor and then activates an intracellular signaling pathway. The function of the pathway will be to alter the cell directly or indirectly by changing gene expression. (eg VEGF, shh)
maternal decidua - region of uterine endometrium where blastocyst implants. undergoes modification following implantation, decidual reaction.
maternal sinusoids - placental spaces around chorionic villi that are filled with maternal blood. Closest maternal/fetal exchange site.
mesoderm - the middle layer of the 3 germ cell layers of the embryo. Mesoderm outside the embryo and covering the amnion, yolk and chorion sacs is extraembryonic mesoderm.
myocardium - muscular wall of the heart. Thickest layer formed by spirally arranged cardiac muscle cells.
pericardium - covers the heart. Formed by 3 layers consisting of a fibrous pericardium and a double layered serous pericardium (parietal layer and visceral epicardium layer).
pharyngeal arches (=branchial arches, Gk. gill) series of cranial folds that form most structures of the head and neck. Six arches form but only 4 form any structures. Each arch has a pouch, membrane and groove.
placenta - (Greek, plakuos = flat cake) refers to the discoid shape of the placenta, embryonic (villous chorion)/maternal organ (decidua basalis)
placental veins - paired initially then only left at end of embryonic period, carry oxygenated blood to the embryo (sinus venosus).
protein hormone - usually a protein distributed in the blood that binds to membrane receptors on target cells in different tissues. Do not easliy cross placental barrier.
sinus venosus - cavity into which all major embryonic paired veins supply (vitelline, placental, cardinal).
splanchnic mesoderm - portion of lateral plate mesoderm closest to the endoderm when coelom forms.
steroid hormone - lipid soluble hormone that easily crosses membranes to bind receptors in cytoplasm or nucleus of target cells. Hormone+Receptor then binds DNA activating or suppressing gene transcription. Easliy cross placental barrier.
syncitiotrophoblast extraembryonic cells of trophoblastic shell surrounding embryo, outside the cytotrophoblast layer, involved with implantation of the blastocyst by eroding extracellular matrix surrounding maternal endometrial cells at site of implantation, also contribute to villi. (dark staining, multinucleated).
truncus arteriosus - an embryological heart outflow structure, that forms in early cardiac development and will later divides into the pulmonary artery and aorta. Term is also used clinically to describe the malformation where only one artery arises from the heart and forms the aorta and pulmonary artery.
vascular endothelial growth factor - (VEGF) protein growth factor family that stimulates blood vessel growth, a similar factor can be found in the placenta (PIGF).
vitelline blood vessels - blood vessels associated with the yolk sac.
waste products - products of cellular metabolism and cellular debris, e.g.- urea, uric acid, bilirubin.