Unit 1: Cardiac Anatomy Flashcards
What is the size of the heart?
Size of a clenched fist
Where is the apex of the heart located?
- Bottom of left ventricle
- When supine: 5th intercostal space
- When upright: 6th intercostal space
Where is the base of the heart?
Left and Right Atria
Where is the heart situated in the chest?
2/3 on the left, rotated so when you open you see more of right ventricle
What are the 4 coverings of the heart from the outside to the inside?
Pericardium → epicardium → myocardium → endocardium
In prenatal circulation, what is the ductus venosus?
Oxygenated blood flows from placenta, skips the liver and goes directly to the IVC through the dectus venosus
In prenatal circulation, what is the foramen ovale?
This valve is open between in utero and allows blood to flow from the right atirum to the left atrium
Which side of the heart has higher pressure during prenatal circulation?
Right side has higher pressure.
In prenatal circulation, what is the ductus arteriosus?
Blood leaving the right ventricle is pumped up into the pulmonary trunk. Only a small amount of blood goes to the lung. The rest goes through the ductus arteriosus, bypassing the lungs, and into the aorta to the rest of the body.
Why do prenatal lungs recieve blood if they are not using their lungs to breathe?
For nutritional purposes, NOT gas exchange.
Where does gas exchange occur in prenatal circulation?
The placenta
In postnatal circulation, what causes the foramen ovale to close?
After birth, dec pressure in right atrium and increased pressure in left atrium changes pressure gradient and forces it closed
- anatomical closur occurs at 2-3 months (up to 1 y/o)
In postnatal circulation, what is it call when the foramen ovale remains open? What happens?
Patent Foramen Ovale: Heart acts like it did in utero - fluid remains in lungs and blood mixes from the righ atrium to the left atrium.
What is meconium aspiration and what can it lead to?
- Aspiration of baby black poop during birth process
- Leads to increased pulmonary vascular resistance resulting in a right-to-left shunt → keeps foramen ovale open.
In postnatal circulation, the ductus arteriosus closes after 2-3 weeks (up to 3 months). How does it close?
Duct actively constricts in response to the presence of oxygen
In postnatal circulation, what is it called if the ductus arteriosus does not close? What happens as a result?
Patent Ductus Arteriosus: Hypoxia will cause duct to remain open and could cause left-to-right shunt
- Blood stays in loop and does not circulate to lungs
What is the total blood volume in an adult?
5-5.5 liters