2. Cardiac imaging & CVS anatomy Flashcards
List the different imaging techniques that can be used to assess cardiac structure and functioning
- X-rays
- Nuclear imaging (e.g PET)
- Cardiac MRI
- CT scanning
what is the CT pulmonary angiography?
This is an imaging technique that can be used to study the pulmonary arteries.
It can be used to identify blood clots or narrowing in the pulmonary arteries.
describe the flow of blood through the chambers of the heart, including the valves it goes through
Deoxygenated blood from the cells of the body enter the right atrium of the heart through the inferior and superior vena cava. the blood then flows to the right ventricle through the tricuspid valve. when the right ventricle contracts, the blood flows into the pulmonary artery through the pulmonary valve and to the lungs.
Oxygenated blood from the lungs enters the left atrium via the pulmonary vein. it then flows into the left ventricle through the mitral valve and then to the aorta through the aortic valve and to the rest of the body.
how many pulmonary veins are there?
4 - two from each lung
two on the right side and two on the left
what is the main difference between the left and right ventricle?
left ventricle is much thicker as it has higher pressure
describe the 3 layers of arteries
tunica intima - composed of an elastic membrane lining and smooth endothelium
tunica media - composed of smooth muscle and elastic fibres
tunica extern/adventitia - composed of collagen and elastic fibres(connective tissue)
how does size of arteries affect its structure?
large arteries e.g. aorta have more elastic tissue which allows it to expand.
medium sized arteries are more muscular as they are the distributing arteries
small sized arteries are also muscular as they are resistance vessels and control blood pressure
describe the structure of the aorta
The aorta is the largest artery in the body.The aorta is divided into four sections:
The ascending aorta, the aortic arch, the descending aorta and the abdominal aorta.
describe the sections of the aorta
- The ascending aorta begins at the opening of the aortic valve in the left ventricle of the heart. The coronary arteries branch off the ascending aorta to supply the heart with blood.
- The aortic arch curves over the heart, giving rise to branches that bring blood to the head, neck, and arms.
- The descending thoracic aorta travels down through the chest. Its small branches supply blood to the ribs and some chest structures.
- The abdominal aorta begins at the diaphragm, splitting into smaller arteries in the lower abdomen. Most of the major organs receive blood from branches of the abdominal aorta.
what is the function of the aorta?
The aorta is used to distribute oxygenated blood to all parts of the body.
Give the equation for Cardiac output
CO= HR x SV
Compare the HR, CO and SV in a 70kg under resting conditions and during exercise
At rest:
HR= 60-90bpm
SV= 55-83 ml/beat
CO= 5L/min
During exercise:
HR- 150-200bpm
SV= Up to 200ml/ beat
CO= 20-35L/ min
what are the 3 layers of the heart?
Epicardium - serous membrane, smooth outer surface of heart. contains loose connective tissue and adipose tissue.
Myocardium - middle layer composed of cardiac muscle cell and responsible for heart contracting
Endocardium - smooth inner surface of heart chambers
what are pectinate muscles?
muscular ridges in auricles and right atrial wall
what are trabeculae carnae?
muscular ridges and columns on inside walls of ventricles
what are auricles and what are their function?
One auricle is attached to each of the anterior surfaces of the outer-walls of the atria. Their purpose is to increase the capacity of the atrium, and so also increase the volume of blood that it is able to contain
what is the phrenic nerve?
The phrenic nerve is a mixed nerve that originates from the the neck (C3, C4, C5) and descends through the thorax to innervate the diaphragm, to allow contraction.
what is the function of the phrenic nerve?
It is important for breathing and is the only source of motor innervation to the diaphragm.
It passes motor information to the diaphragm and receives sensory information from it. There are two phrenic nerves, a left and a right one.
What is a pericardial effusion?
Pericardial effusion (“fluid around the heart”) is an abnormal accumulation of fluid in the pericardial cavity.
what is the effect of pericardial effusion?
Due to the limited amount of space in the pericardial cavity, fluid accumulation leads to an increase in pressure in the pericardial space which can negatively affect heart function.
A pericardial effusion with enough pressure to adversely affect heart function is called cardiac tamponade.
what are the 4 main valves in the heart?
- The mitral/ bicuspid valve (atrioventricular valve)
- The tricuspid valve (atrioventricular valve)
- The aortic valve (semilunar valve)
- The pulmonary valve (semilunar valve)
describe the location and function of the mitral valve?
The mitral valve is found in the left side of the heart, it connects the left atrium to the left ventricle.
It prevents a backflow of blood from the ventricles into the atria.
describe the location and function of the tricuspid valve?
The tricuspid valve is found in the right side of the heart and it connects the right atrium to the right ventricle.
It prevents a backflow of blood from the ventricles into the atria.
describe the location and function of the aortic valve?
The aortic valve is found at the base of the aorta and it’s used to prevent a back flow of blood form the arteries into the ventricles
describe the location and function of the pulmonary valve?
The pulmonary valve is found at the base of the pulmonary trunk and it’s used to prevent a back flow of blood from the arteries into the ventricles.
What is aortic stenosis?
Aortic valve stenosis occurs when the heart’s aortic valve narrows.
This narrowing prevents the valve from opening fully, which reduces or blocks blood flow from your heart into the main artery and onward to the rest of your body.
what is the effect of aortic stenosis?
When the blood flow through the aortic valve is reduced or blocked, your heart needs to work harder to pump blood to your body. Eventually, this extra work limits the amount of blood it can pump, and this can cause symptoms as well as possibly weaken your heart muscle.
What is aortic valve regurgitation?
Aortic valve regurgitation — or aortic regurgitation — is a condition that occurs when your heart’s aortic valve doesn’t close tightly.
Aortic valve regurgitation allows some of the blood that was pumped out of your heart’s main pumping chamber (left ventricle) to leak back into it.
how many main coronary arteries are there?
3
the right coronary artery, the left anterior descending and the circumflex artery. The two main branches from the aorta are the right and left coronary arteries but the left coronary artery quickly branches into the LAD and circumflex artery.
which areas of the heart does the LAD and circumflex artery supply?
The left anterior descending artery perfuses the interventricular septum and anterior wall of the left ventricle
The left circumflex artery runs towards the back of the heart and perfuses the lateral and posterior aspects of the left ventricle
which areas of the heart does the right coronary artery supply?
The right marginal arteries perfuse the right ventricle and the posterior descending artery perfuses the left ventricular posterior and inferior walls.
what is tranoesophageal echocardiography?
Transesophageal echocardiography (TEE) is a test that produces pictures of your heart. TEE uses high-frequency sound waves (ultrasound) to make detailed pictures of your heart and the arteries that lead to and from it.
what does Coronary arterial dominance mean?
Coronary arterial dominance is defined by the vessel which gives rise to the posterior descending artery (PDA), which supplies the myocardium of the inferior 1/3rd of the interventricular septum.
Most hearts (80-85%) are right dominant where the PDA is supplied by the RCA. The remaining 15-20% of hearts are roughly equally divided between left dominant (~10%) and codominant (~20%). In left dominant hearts the PDA is supplied by the LCx (circumflex) wrapping around the left atrioventricular groove or less commonly the LAD coursing around the apex of the heart. In a codominant heart a single or duplicated PDA is supplied by branches of both the RCA and LAD or LCx.
What is a CT angiography and what can it be used for?
A computed tomography angiogram (CT angiogram) is a test that uses X-rays to provide detailed pictures of the heart and blood vessels that go to the body.
A CT angiogram can show narrowed or blocked areas of a blood vessel.
What is the Cardiac-thoracic ratio?
This a method used to measure the size of the heart.
Accurate assessment of the size of the heart is carried out using a Posterior-Anterior X-ray.
The ratio should be less than 50% as this mean that the heart size is within normal limits.
If the size of the heart is greater than 50% it can indicate pathology.
Describe the coronary veins
The coronary veins include the great cardiac vein, the middle cardiac vein, the small cardiac vein, the smallest cardiac veins, and the anterior cardiac veins.
describe the coronary sinus
The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the myocardium of the heart.
It delivers less-oxygenated blood to the right atrium.
