Lecture 24 Flashcards
First stage of formation of the heart the formation of the (2) from the…
pleuropericardial cavity and cardiogenic plate from the lateral mesoderm
formation of the simple, tubular heart includes _____ which is when ______
head folding
tissues in from of neural plate are inverted 180 degrees
What does the 4 chambered heart arise from, what are the first chambers to be created
four chambered heart arises from cranial and caudal AV endocardial cushions
grow towards each other forming R and L AV canal
Where does the IV septum grow from and what does it unite with?
grows from the ventral floor to divide R and L ventricles uniting with the AV cushions via gelatinous membrane
Separation of the atria(2)
septum primum- descends in caudoventral direction and becomes flap for foramen ovale
septum secondum- develops thick partition, definitive septum
The aorta has
spiral septum which separates pulmonary trunk and aorta
What are the 4 distinct circulations that exist
Yolk sac vitelline circulation
Alantoic Umbilical circulation
Systemic circulation
Pulmonary circulation
Yolk sac vitelline circulation(2)
embryo to yolk sac -
omphalomeseteric artery
from yolk sac to heart-
omphalomesenteric vein
Allantoic/umbilical circulation
from heart ->allantois
*allantoic or umbilical artery
from allantois ->heart
*allantoic or umbilical vein
systemic circulation
heart->embryonic body
paired ventral and dorsal aorta
embryonic body->heart
*cardinal veins
Pulmonic circulation
most of the blood is shunted via the ductus arteriosus (6th arch) to aortic circulation
Aortic arches
all 6 are never present at one time
3,4,6 contribute to final vascular path
in the fetus, which side of the heart is doing more work
right
what capacity does the fetal heart work at?
full capacity
What type of resistance does the placenta have and what does it result in
placenta is low resistance so systemic arterial circulation is low resistance
while lungs are high resistance (collapsed)
