Session 2 - Heart development (1) Flashcards
Why does the CVS begin to develop at week 3 of embryological development?
The embryo can no longer rely on simple diffusion to receive nutrients
What does lateral folding of the trilaminar disc do for the formation of CVS?
Allows them to fuse and create the heart tube
What type of folding brings the heart tube into the thorax?
Cephalocaudal
What is shown in the image?
The heart tube
What is A?
Bulbus Cordis
What is B?
Ventricle
What two things is section C comprised of?
The atrium and sinus venosus
What is D?
The aortic roots
What is E?
The truncus arteriosus
What is looping driven by?
Expansion of the heart tube
How does the cephalic portion of the heart tube loop?
Ventrally, Caudally and to the right
How does the caudal portion loop?
Dorsally, cranially and to the left
What does looping of the heart tube achieve? (4)
* Primordium of right ventricle closest to outflow tract
* Primordium of left ventricle closest to inflow tract
* Atrium dorsal to bulbus cordus i.e. inflow is dorsal to outflow
* Creates the transverse pericardial sinus \ arteries are in front of the veins
What is A?
Outflow tract
What is B?
Right ventricle
What is C?
Left ventricle
What is D?
Atria
How does the atrium connect with the ventricle after looping?
Atrioventricular canal
What does the atrioventricular canal drive?
Partioning of the heart
What does the right atrium develop from?
* Most of the primitive atrium
* Absorption of the sinus venosus
What does the left atrium develop from?
* Small portion of the primitive atrium
* Absorption of the proximal parts of the pulmonary veins (creates oblique pericardial sinus)
What does the RA receive venous drainage from?
Receives venous drainage from
- Vena Cavae
- Coronary Sinus
Where does the LA receive oxygenated blood from?
receives oxygenated blood from the lungs
Another exciting heart for you guys and gals to label
What is A?
Superior vena cava
What is C?
Inferior vena cava
What is D?
Coronary sinus
What is E?
Pulmonary veins
Why does the foetus have two separate circulatory systems?
Lungs non-functional, so circulation must go through it
How does foetus receive oxygen in utero?
* Receives oxygenated blood from the mother via placenta and umbilical vein
How does foetal circulation differ from developed?
- Lungs by-passed by foetal circulatory shunts
- Shunt to bypass the right ventricle and lungs
Why must some blood be pumped by right ventricle, despite it being useless as lungs not in use?
As muscle must build strength via use
What do early arterial systems begin as?
Early arterial system begins as a bilaterally symmetrical system of arched vessels which then undergo extensive remodelling to create the major arteries leaving the heart.
What is the name of the shunt which bypasses lungs after blood has been pumped for right ventricle?
Ductus arteriosus
What do the right and left 4th arches of the aortic arch become?
* Right 4th arch > proximal part of the right subclavian artery
* Left 4th arch > arch of the aorta
What do the right and left arches of the 6th arch become?
* Right 6th arch > right pulmonary artery
* Left 6th arch > pulmonary artery & ductus arteriosus
What is the nerve corresponding to the sixth aortic arch?
Reccurent laryngeal nerve
What two factors influence the course of the laryngeal nerve on the right and left side?
–caudal shift of the developing heart & expansion of the developing neck region
–the need for a fetal shunt between PT & aorta
