Session 3 Lectures Flashcards
Which week does the embryo fold & does the position of carcinogenic field change?
In week 4 of embryonic period (embryonic period = week 3-8)
Yes the position changes
Suggest a reason why congenital heart defects are one of the most common defects
There are different circulatory needs of the fetus and newborn baby - need to be able to create both and switch over immediately after birth
What is at the inlet of the primitive heart tube?
Sinus venous and primitive atrium
What is at the outlet of the primitive heart tube?
Aortic roots
Suggest why cardiac looping takes place
To maximise the amount of space the heart has within the pericardial sac
What is the primitive heart tube composed of?
Fusion of 2 endocardial tubes
What does right atrium develop from?
Most of the primitive atrium and sinus venosus (inlet of heart tube)
What does left atrium develop from? And why is it smoother?
A small portion of primitive atrium and proximal parts of the pulmonary veins
These are made of smooth muscle so left atrium is smoother
In the fetus the lungs don’t work - where does oxygenation and removal of CO2 take place?
At the placenta
When oxygenated blood enters the umbilical vein what does it reach first and how does it bypass this?
It reaches the liver first
Shunt of blood to go directly to inferior vena cava
This shunt is called the ductus venosus
In the fetus oxygenated blood travelling from inferior vena cava reaches right atrium and is shunted across to pulmonary trunk. What is this shunt called?
Does some blood go into right ventricle first?
Foramen ovale
Yes some does reach right ventricle so that this muscle properly develops
In the fetus blood eventually reaches pulmonary trunk and is shunted to aorta as it is already oxygenated. What is this shunt called?
Ductus arteriosus
What nerve becomes hooked around the pulmonary trunk and aorta in development?
The left recurrent laryngeal nerve
What does PDA stand for and what is the condition?
Patent ductus arteriosus
When the ductus arteriosus doesn’t close after birth - blood is now shunted from aorta to pulmonary trunk (down pressure gradient)
What are the 2 septums called? What are the 2 hole called that form (1 in each)?
Septum primum and septum secundum
Ostium secundum and foramen ovale
What happens to the foramen ovale in healthy newborns?
It is closed by the pressure of the left atrium (forcing the septum primum and septum secundum close together)
What is hypoplastic left heart syndrome?
The left ventricle and ascending aorta fail to develop properly
A patent foreman ovale or atrial septum defect is also present and blood supply to systemic circulation is via a patent ductus arteriosus