CVS Flashcards
What are the 3 layers of Arteries + Veins?
Tunic Intima - Next to lumen
Tunica Media
Tunica Adventitia - Outer layer
Where is the most common site of an Atrial Septal Defect?
Foramen Ovale
What is a Patent Foramen Ovale + why is it not a true Atrial Septal Defect? How is it clinically relevant?
Generally clinically silent since the higher left atrial pressure causes functional closure of the flap valve.
Can be a route for venous embolism to enter the systemic circulation, this is called a Paradoxical Embolism
Where is the most common site of Ventricular Septal Defects?
Membranous part of the septum
What is a Patent Ductus Arteriosus + how can it cause problems clinically (Eisenmenger Syndrome)?
Failure to close the Ductus Arteriosus leads to blood flow from the aorta to the pulmonary artery, a mechanical murmur can constantly be heard as the pressure is always higher in the aorta.
Chronic left to right shunt can cause vascular remodelling of the pulmonary circulation + an increase in pulmonary resistance. If pulmonary resistance increases past the systemic resistance then the shunt can be reversed. This leads to cyanosis
What is coarctation of the aorta and how would it be detected?
Narrowing of the aortic lumen at the Ligamentum Arteriosum (former Ductus Arteriosus). The narrowing of the aorta can lead to left ventricular hypertrophy. Because the vessels to the head + upper limbs emerge proximal to the coarctation it leads to upper body hypertension. Patients will also have weak + delayed femoral pulse
What is Tetralogy of Fallot?
Group of 4 lesions occurring together, these are;
- Ventricular Septal Defect
- Overriding Aorta
- Pulmonary Stenosis
- Right Ventricular Hypertrophy
Pulmonary stenosis causes right ventricular hypertrophy, this along with the VSD + overriding aorta allow right to left shunting, resulting in cyanosis.
What is Tricuspid Atresia?
Lack of development of the tricuspid valve so no inlet into the right ventricle. There must therefor me a complete right to left shunt of all blood returning to the right atrium to allow blood to flow to the lungs
What is Transposition of the Great Arteries?
Aorta + Pulmonary Artery are swapped resulting in two unconnected parallel circuits. This is not compatible with life after birth without a shunt to allow the two circuits to communicate
What is a Hypoplastic Left Heart?
Failure of the left ventricle and ascending aorta to develop properly. An ASD is present and blood supply to systemic circulation is via a Patent Ductus Arteriosus. Not compatible with life
What is the Sympathetic + Parasympathetic stimulation of the heart?
Sympathetic - β1 (NA)
Parasympathetic - M2 (Ach)
What is the Sympathetic + Parasympathetic stimulation of the airways?
Sympathetic - β2
Parasympathetic - M3
What is Viscosity?
The amount that fluid layers resist sliding over one another
What is Reactive Hyperaemia?
If circulation is cut off for a while then restored a large amount enters due to the build up of vasodilator metabolites
Describe the CVS response to eating a meal
- Increased activity of gut produces metabolites + causes local vasodilation causing fall in TPR + arterial pressure and increase in venous pressure
- Rise in venous pressure + fall in arterial causes rise in Cardiac output
- Extra pumping increases Arterial + decreases Venous pressure
