HE 23 Cardiovascular System II Flashcards
Origin of Blood Vessels and Heart
Mesoderm-lateral plate mesoderm-visceral mesoderm
within mesoderm vasculogenesis occurs (formation of new BVs where none existed previously).
-Hemangioblasts- Blood Islands
- progressively form BV endothelium lining, and are the origin of the heart and major embryonic vessels
- first appear surrounding yolk sac
Aortic Arches products in dev
aortic arches: blood to head and neck from fetal heart (mixed)
undergo series of rearrangements
-become great arteries (central aa) wedge shaped portion of aortic arch, DUCTUS ARTERIOSIS (ligamentum arteriosum)
dorsal aorta in development
blood from heart to body, YS and Placenta (mixed)
two fuse to become one, and form a single aorta
-part of AA, thoracic aorta, ab aorta
Cardinal Veins
Blue veins from body back to heart- Venus blood drainig into heart DEOX
become internal jugular veins, BC vv, SVC azygous system and most of IVC
Vitelline Veins
Veins from YS draining to heart, DEOX
- GI associated BV’s (abdominal and GI)
- umbilical arteries in P&P
Liver Bypass
Ox blood in Umb vein does not need filtration
-gets filtration from the placenta
shunts blood STRAIGHT through the liver in Ductus Venosus (IVC)
Pulmonary Bypass
lungs not needed to oxygenate blood, placenta
- collapsed and would take too much pressure, need just enough to survive
- blood enters RA through ductus venosus (liver bypass) and goes through Foramen Ovale to bypass pulmonary circulation to LA to LV to AORTA
SVC blood flow
flows into RA as DeOX blood combines with IVC Ox blood, go to RV and Pulmonary trunk, bypass pulmonary circulation via DUCTUS ARTERIOSUS (ligamentum arteriosa) to AA
Breathing begins
DA closes
FO closes
-lungs inflate and change in P
umb blood Vessels cut.
these changes do not happen instantaneously
-days weeks months year
Patency
structures remain open or partially open past normal time range.
