module 6: embryology 4

what do angioblasts create?

the walls of blood vessels

where do angioblasts differentiate from?

mesodermal cells

what are blood islands

small pockets of angioblasts within the mesoderm

what is endothelium?

its the lining of blood vessels - made from angioblasts

what forms the primitive heart tubes?

when 2 endocardial tubes form together

what are the 4 dilations of the primitive heart tube?

1. bulbus cordis

2. ventricle

3. atrium

4. sinus venosus

what end is the bulbus cordis closets to?

closest to arteriole end?

what does the arterial end of the heart do?

the exit point for blood

what end is the sinus venosus end on?

the venus end

what does the venous end of the heart do?

the entrance point for blood

why does the heart begin to bend as its growing?

because of the pericardial cavity surrounding it

which way does the atria move in development?

backwards and up

which way do ventricles move in development?

forwards and down

by what day is the heart in its full adult form?

day 28

what does the bulbus cordis become once the heart is fully formed?

most of the right ventricle

what does the ventricle become once the heart is fully formed?

the left ventricle

what does the atrium become once the heart is fully formed?

the left atrium

what does the sinus venosus become once the heart is fully formed?

the SA node and the right atrium

what is the interventricular septum?

a muscular wall between the 2 ventricles - also known as foramen ovale

what is the interventricular septum composed of?

1. the septum secundum → right side of atrium

2. the septum primum → left side of atrium

what does blood circulation in the fetus look like?

right atrium → interventricular septum → left atrium → left ventricle → body

why does blood bypass the lungs as birth?

because the lungs are deflated

why does blood also bypass the liver?

because the placenta filters the blood - which does the job of the liver

what happens to the lungs when the baby is born?

the detachment of the placenta causes a drop in axygen singlialing the baby to take its first breath →the lungs then inflate -. causing pressure in the left atrium to be high and close the formen ovale

what does the ductus venous bypass?

bypasses the liver

what does the ductus arterioles bypass?

will bypass the lungs

what does the umbilical vein carry?

oxygen rich blood

what does the umbilical vein carry?

oxygen poor blood

what does the foramen ovale become after the baby is born?

fossa ovalis

what does the ductus arteriosus become?

ligamentum arterosum

what does the ductus venosus become after baby is born?

the ligamentum venosum

what does the umbilical vein become after the baby is born?

ligamentum terries

what does the umbilical arteries become once baby is born?

medial umbilical ligaments

where do lung buds come from?

they are evaginations of the foregut

where do lung buds branch off of?

the developing trachea

what are the branches of the lungs called?

bronchi

how many times does happens in the fetus

17 times → and then 24 times when born

what does the 5th week if lung development look like?

we have left and right primary and secondary bronchi

what does the 6th week if lung development look like?

right lung: primary secondary and tertiary bronchi

left lung: primary and secondary bronchi

what does the 7th week if lung development look like?

right lung: superior, middle, inferior lobes

left lung: superior and inferior lobes

in the 7th week bronchi → become lobes

how many lobes does the right and left lung have

right has 3

left as 2 - to accommodate for the heart