Lecture 5: Cardiology Flashcards
What are the divisions of the mediastinum?
- Superior mediastinum
2. Inferior mediastinum
- Anterior mediastinum- in front of the heart
- Posterior mediastinum- behind the heart
- Middle mediastinum- da heart
What separates the superior mediastinum from the anterior mediastinum?
Sternal angle
What separates the anterior mediastinum from the posterior mediastinum?
Heart
What occupies the middle mediastinum?
Heart
What occupies the superior mediastinum?
Great vessels and thymus
Features of the heart
- Two sided
- Four chambers
- Self-initializing
4. Self-adjusting
Right side of heart gets deoxygenated blood from superior and inferior vena cava–> lungs to be oxygenated.
L side of the heart gets O2 rich blood from the lungs and pumps it to the body via the aorta.
What are the layers of the heart?
- Epicardium- outmost layer made up of visceral serous pericardium
- Myocardium- thick layers of cardiac muscle, below the epicardium
- Endocardium- thin internal endothelial and subendothelial layer that lines the insideof the chambers of the heart and valves.
- Fibrous skeleton of the heart
CN: What is a myocardial infarction?
Lack of blood blow to the myocardium, often caused by a blockage in the coronary artery.
Coronary atherosclerosis is a buildup of lipids inside the coronary arteries that decreases the size of the lumen, increasing the liklihood of a blockage.
CN: What is angina pectoris?
Angina pectoris is pain that originates in the heart but is referred to the left upper limb. It causes stragling pain in the chest.
Cause is often a obstructed coronary artery that causes ischemia in the myocardium.
What is the fibrous skeleton of the heart?
Dense collagenous fibers that:
- Is an attachment point for the myocardium
- Holds open cuspid valves
- Holds open the AV and semilunar orifices.
- Serves an electrically insulated barrier between the atria and ventricle.
What is the electrically insulated barrier between the atria nad ventricle that the fibrous skeleton of the heart makes?
Membranous atrioventricular septum
What are the borders of the heart?
- Left- left margin (left ventricle)
- Inferior- right margin (right ventricle)
- Superior (R and L atria and has the exit point for the aorta and pulmonary trunk).
- Right (right atrium)
What is the ligamentum arteriosum?
Remnants of the embryological ductus arteriosus, which shunted blood from the pulmonary trunk to the aorta to bypass the nonfunctional lungs.
It communicates between the pulmonary trunk–>aortic arch.
-L recurrent laryngeal n. of the vagus n loos around the aortic arch and the ligamentum arteriosum then goes to the larynx.
CN: compression of the L recurrent laryngeal nerve
L recurrent laryngeal N goes under the ligamentym arteriosym.
Because it creates a weak spot in the aorta, it is prone to aneurisms, which can compress the nerve and make it hard to speak
What are the internal features of the RIGHT ATRIUM?
- Sinus venarum–> smooth, thin wall muscle
- Pectinate muscle of the R atrium --> rough muscular wall. right auricle
- Interatrial septum–> smooth walle between the two atria and located AROUND fossa ovalis. Interatrial septum is surrounded by the sinus venaris
- Valve for the opening for the coronary sinus
- Crista terminalis will seperate the rough and smooth wall.
What is the embryonic remnant of the foramen ovalis?
Fossa ovalis
What is the coronary sinus?
How the coronary veins drain back into the heart
CN: Atrial septal defects
Atrial septal defects occur when the foramen ovalis does not close completely.
15-20% of adults have a small opening in their foramen ovale, which is not bad because the left atrium contracts harder than the right, so very little blood goes from the right–> left atrium.
Larger openings in the interatrial septum allow oxygen rich blood to mix with oxygen depleted.
What is the purpose of the foramen ovalis?
It allows blood to pass from 1 atrium–> another.