5: Cardiology Flashcards
Divisions of the mediastinum
- Superior mediastinum
2. Inferior mediastinum -> anterior, middle, and posterior mediastina
What forms the superior and inferior mediastinum
Sternal angle
What is in the middle mediastinum
Heart
What is the start of the systemic circulation? Start of the pulmonary?
Systemic: LA
Pulmonary: SVC and IVC
What typically causes MI’s
Lack of blood flow to a specific area of myocardium, usually due to coronary A blockage
Coronary atherosclerosis
Buildup of lipids on internal walls of coronary A’s -> decreases sizes of lumens, increasing likelihood of an embolus
Angina pectoris
Pain that originates in heart -> strangling pain in chest in a distinct pattern
What usually causes angina pectoris
Narrow/obstructed coronary A’s -> ischemia of myocardium
What is the ligamentum arteriosum
Adult remnant of the ductus arteriosus (shunts blood from pulmonary trunk to aorta)
Where does ligamentum arteriosum span?
Superior pulmonary trunk -> inferior border of aortic arch
What nerve loops around the aortic arch and ligamentum arteriosus?
Left recurrent laryngeal N (of the vagus)
Common atrial septal defect
PFO: patent foramen ovale
Cardiac catheterization
Inserting a catheter into the femoral vein -> IVC to allow radiographic visualization of the RA, RV, pulmonary trunk, and pulmonary arteries
Ventricular septal defects
Particularly susceptible to defects bc of embryo logically divergent tissues; all defects are clinically relevant bc they allow mixture of O2 rich and depleted blood
Artificial cardiac pacemaker
Produces regular electrical impulses to the ventricles via electrodes
Where are electrodes inserted with artificial pacemakers?
Through a large vein to the SVC, into the RA -> into endocardium of trabeculae carnae of RV
How does cardiac referred pain work?
Ischemia stimulates visceral pain sensory fibers that share a spinal ganglion with somatic sensory fibers in areas of the upper limb/superolateral chest wall
Where does anginal pain typically refer?
Area innervated by left medial brachial cutaneous N, left sub sternal area, left pectoral area, medial left UE
Transverse pericardial sinus in surgery
Space that allows surgeons to access the area posterior to the aorta and pulmonary trunk to clamp/insert tubes of a bypass into these large vessels
Pericarditis
Inflammation of pericardium - > can roughen pericardium and cause friction -> pericardial friction rub that can be heard on auscultation
What happens if pericarditis is left untreated?
Pericardium can calcify
Pericardial effusion
Pericarditis can result in accumulation of fluid/pus in pericardial sac -> compresses heart -> cardiac tamponade
Pericardiocentesis
Drainage of fluid/blood/pus from pericardial sac to relieve cardiac tamponade
Three layers of the heart
- Epicardium: outermost of visceral serous pericardium
- Myocardium: thick muscular layer of spiraling, overlapping layers of muscle
- Endocardium: thin internal endothelium lining chambers
Three functions of the fibrous skeleton of the heart
- Produces attachment points for: myocardium, valves
- Supports/strengthens AV and semilunar orifices
- Electrically insulated barrier between atria and ventricles
What do right and left atrioventricular groove house?
Right: R coronary A
Left: coronary sinus
What do anterior and posterior interventricular grooves house?
Anterior: anterior interventricular A, great cardiac V
Posterior: posterior interventricular A, middle cardiac V
What does the external sulcus terminalis correspond to internally?
Crista terminalis
Apex of the heart
Inferolateral part of LV that projects to the left
Interatrial septum
Between two atria, houses fossa ovalis
Right atrioventricular orifice
Passage from RA to RV with tricuspid valve
Which atria/ventricle are thicker walled?
Left A/V are thicker
Interventricular septum + what it houses
Separates two ventricles; AV bundle, R and L bundle branches, subendocardial branches
Where is the sinoatrial node?
In myocardium, where SVC meets RA
Where is the AV node?
Interarterial septum, near opening of coronary sinus
AV bundle function
Crosses electrically insulated barrier provided by fibrous skeleton -> distributes impulse from AV not into L and R AV bundles
Subendocardial branches (Purkinje fibers)
Distribute impulses from R and L AV bundles -> interventricular septum
Two parts of the pericardium
- Serous: parietal + visceral
2. Fibrous: tough
Parietal vs visceral serous membrane of pericardium
Parietal: adheres to fibrous pericardium
Visceral: adheres to heart, making up epicardium
Oblique and transverse pericardial sinuses
Oblique: posterior to base of heart
Transverse: traverses origins of great vessels
