development of the cardiovascular system 2 Flashcards
define vasculogenesis
the new formation of a primitive vascular network
define angiogenesis
the growth of new vessels from pre-existing blood vessels
what does the aortic sac form from?
it is an extension of the truncus arteriosus of the primordial heart
what do the aortic branches develop from?
the aortic sac
what join together to form aortic arches?
aortic branches and pharyngeal arch arteries
how many pairs of aortic arches are there?
6, although not all are present at the same time
where do the aortic arches terminate?
the dorsal aorta
what is the fate of the 1st and 2nd aortic arches?
they disappear early but the remnants of the 1st arch form the maxillary artery
what is the fate of the 3rd aortic arch?
it becomes the commencement of the internal carotid artery and is therefore named the acrotid arch
what is the fate of the right 4th aortic arch?
the right subclavian vein
what is the fate of the 4th left aortic arch?
the distal part of the aortic arch
what is the fate of the 5th aortic arch?
it either doesn’t form or it regresses
what is the fate of the right 6th aortic arch?
the proximal part becomes the proximal part of the right pulmonary artery
what is the fate of the left 6th aortic arch?
the left pulmonary vein and the ductus arteriosus
what does the ductus arteriosus become after about 1-3 months?
the ligamentum arteriosum
what is an aberrant right subclavian artery?
a developmental condition in which the right subclavian artery has an anomalous origin (in the aortic arch) and loops round the trachea. this may compress the trachea, but is usually assympomatic
what causes an aberrant right subclavian artery
regression of the right 4th aortic arch and the right dorsal aorta
what is a double aortic arch?
a condition in which an abnormal right aortic arch develops in addition to the normal left arch. this right arch loops round the oesophagus and the trachea, which can cause constriction of both structures
what is patent ductus arteriosis?
a conditin in which the ductus arteriosus fails to close, causes breathlessness and poor weight gain after the first year of life
what is coarctation of the aorta?
a condition in which the aorta is narrowed, usually in the area in which the ductus arteriosus enters.
what is a preductal coarctation?
a narrowing of the aorta before the ductus arteriosus enters
what is a postductal coarctation?
a narrowing of the aorta after the ductus arteriosus?
what is the circulation in the yolk sac called?
vitelline circulation
what is the circulation in the umbilical cord called?
umbilical circulation
what is the circulation in all the embryo (excluding the umbilical cord and yolk sac)?
the cardinal circulation
how many umbilical arteries are there?
2
how many umbilical veins are there?
1
what do the umbilical arteries become?
the proximal portion becomes the internal iliac and superior vesical branches (to urinary bladder)
distal portion degenerates and forms obliterated umbilical arteries and medial umbilical ligaments
what are the fates of the vitelline veins?
vessels in the liver:
- portal vein
- hepatocardiac (liver to heart) part of inferior vena cava)
- liver sinusoids
- superior mesenteric vein
what do the umbilical veins become?
- right umbilical vein obliterates completely
- left umbilical vein obliterates to form teres ligament of adult liver
- ductus venosus vein obliterates to form ligamentum venosum
what are the three cardinal veins?
anterior, posterior and common cardinal veins
where do the cardinal veins drain in to?
the sinus venosus
what enters each horn of the sinus venosus?
a vitelline vein
an umbilical vein
a common cadinal vein
what extends from the truncus arteriosus?
the 6 pairs of aortic arches
what are some venous systemic developmental conditions?
- double IVC
- absence of IVC
- left SVC
- double SVC
when does the lymphatic system form and where?
the end of the sixth week (end of embryonic period)
it develops around the main veins
what is the first evidence of the lymphatic system?
six primary lymph sacs develop, these are later joined by lymphatic vessels
what are the important vascular structures in the circulatory transition at birth?
ductus venosus
foramen ovalis
ductus arteriosus
what is the function of the ductus arteriosus before birth?
it shunts left umbilical blood directly to the IVC, this allows oxygenated blood to bypass the liver
what is the function of the foramen ovale before birth?
allows blood to enter the left atrium from the right so blood can bypass the lungs
what is the function of the ductus venosus before birth?
allows blood that escapes the right atrium to bypass the lungs
how does the ductus venosus change after birth?
it becomes the ligamentum venosum
how does the foramen ovale change after birth?
it closes of and tissue proliferation and adhesion seals it shut
how does the ductus arteriosus change after birth?
it obliterates to form the ligamentum arteriosum
what are the causes of patent ductus arteriosus?
maternal rubella infection
failure of muscular wall to contract
respiratory distress syndrome, lack of surfactant in lungs
what causes coarctation of the aorta?
- incorporation ductus arteriosus tissue into aorta which constricts
- genetic/ environmental factors
