Lecture 9 pt 2 Flashcards
What are the major branches of thoracic aorta?
1) Coronary arteries
2) Right brachiocephalic trunk
3) Arch of aorta
4) Posterior intercostals
What are two branches of the right brachiocephalic trunk?
1) Right common carotid
2) Right subclavian
What two things come off the arch of the aorta?
1) Left common carotid
2) Left subclavian
What is inside the aortic SL valve?
Lateral sinuses contain the right and left coronary arteries
When are the coronary arteries perfused? Why?
During diastole; they open to the aortic valve, so if the valve is stenotic or contracting, the coronary artery has no perfusion
Describe the anatomy of the left and right coronary arteries
1) Left coronary artery is usually the main/ dominant one, has 2 branches: left anterior descending/ anterior IV septal branch (descends along anterior margin of AV septum) and the circumflex branch.
2) Right coronary artery supplies blood to right ventricle, then goes behind and forms right septum and they meet on the posterior side of the apex.
Vagus nerve runs through the mediastinum; what branches off here?
Left and right recurrent laryngeal nerves
Which recurrent laryngeal nerve has a longer course? Why is this important?
Left recurrent laryngeal nerve; more prone to injury
1) What is the carotid body and what does it do?
2) What innervates it?
1) Chemoreceptor; monitors PO2
2) CN 9 (Glossopharyngeal n.) and CN 10 (Vagus n.)
What is the baroreceptor for BP?
Carotid sinus
What nerve innervates the carotid sinus?
CN9
Where is the carotid sinus?
Where the common carotid artery branches into internal and external
What provides autonomic innervation to the heart?
Cardiac plexus’s sympathetic and parasympathetic components
1) What forms the sympathetic part of cardiac plexus?
2) What do the fibers innervate?
1) Presynaptic cell bodies: thoracic lateral horn T1-5(6)
Postsynaptic cell bodies: cervical and superior thoracic paravertebral ganglia
2) SA + AV nodes and cardiac muscle cells
1) What forms the parasympathetic part of cardiac plexus?
2) Where are the postsynaptic cell bodies?
1) Presynaptic fibers of the CN10 (vagus).
2) Postsynaptic cell bodies (intrinsic ganglia) located near SA and AV node, along coronary arteries.
What does sympathetic stimulation do to the heart? What does it dilate?
Increases rate and force, dilates coronary arteries
What does parasympathetic stimulation do to the heart?
Slows heart, reduces force of ctx.
The SA node is set around ______________BPM, and can be modified by sympathetic input, but this also involves the ________________ arteries
60-100; coronary
The electrical cells of the heart pause everything to allow contraction of ________, then goes to bundle of his (anterior and posterior) and Purkinje fibers
atria
What are the two main divisions of the two coronary arteries?
1) RCA (right coronary artery) & posterior IV branch
2) LCA (left coronary artery), Anterior IV branch (LAD) & circumflex branch
What are two branches of the left coronary artery (LCA)?
Anterior IV branch (LAD) & circumflex branch
Name a branch of the right coronary artery
Posterior IV branch
What 6 things do the RCA & posterior IV branch supply?
1) Right atrium
2) Most of right ventricle
3) Part of left ventricle
4) Posterior 1/3 IV septum
5) SA node in 60%
6) AV node in 80%
What 6 things do the LCA’s anterior IV br. (LAD) & circumflex br supply?
1) Left atrium
2) Most of left ventricle
3) Part of right ventricle
4) Anterior 2/3 IV septum
5) AV bundle conducting system
6) SA node 40%
1) What are the most important sinuses of the coronary arteries?
2) When during cardiac cycle are coronary arteries perfused?
1) Right and left aortic sinus
2) Diastole
Why is the left coronary artery involved in more arrythmias than right coronary artery?
Anterior 2/3 of the IV septum is perfused by the anterior IV septal branch of LCA; happens to be where the bundle of His branches run. If you have an occlusion here, you’re likely to affect the conduction system of the heart and see rhythms early on.
Most people are ____________ coronary artery dominant
left
A complete occlusion of a left coronary artery is often called what?
“widowmaker’
Where do the coronary veins empty?
Into coronary sinus in posterior sulcus OR directly into cardiac chambers
The number one cause of death in Americans is?
CAD (coronary artery disease)
What causes CAD?
It’s a life-style disease; smoking, obesity
1) Can CAD be modified?
2) What medical therapies exist for CAD?
3) What surgeries exist for CAD today?
4) What surgery is less common?
1) Yes
2) HTN and T2DM rx, statins, ASA, NTG, B blockers, ACE
3) Percutaneous coronary angioplasty/STENT (DES)
4) CABG (using internal thoracic or great saphenous veins)
Are arteries or veins more susceptible to atherosclerosis? Explain
Arteries more susceptible (unless you used a vein for an arterial graft, then vein more susceptible)
What is the SA node? What is its rate?
Pacemaker, initiates electrical impulse, intrinsic rate is ~ 70/min
Atrial cardiac muscle cells propagate impulse as they do what?
contract
1) What important part of the cardiac cycle happens at the AV node?
2) True or false: Atria and ventricles are electrically insulated and do not communicate under normal circumstances
1) AV node pauses impulse then sends down His bundle
2) True; thanks to cardiac skeleton
What does the bundle of His do? What do its branches supply?
Course down IV septum; dividing into right and left bundle branches to supply the papillary muscles and wall of ventricles.
What does atrial fibrillation (afib) increase risk for?
Increased risk for embolism, HF, etc
What are the 3 parts of the cardiac skeleton?
1) Fibrous skeleton
2) Fibrous rings
3) Fibrous trigones
What are the two types of valves?
SL valves and AV valves
How many leaves do the valves on the left side of the heart have?
1) Mitral valve (2 leaves)
2) Aortic valve (3 leaves)
List the path of blood through the heart including valves
R atrium
Tricuspid valve
R ventricle
Pulmonic valve
L atrium
Mitral valve (2 leaves)
L ventricle
Aortic valve (3 leaves)
What is the most common valvular heart disease that’s brought to clinical attention?
Aortic stenosis
1) What is valvular heart disease?
2) Give 2 examples
1) Stenosis or insufficiency/regurgitation
2) Aortic stenosis and mitral valve regurge
What can valvular heart disease lead to?
Increased demand of heart, which can lead to obstruction or overload
How can you treat valvular heart disease, both surgically and with medication?
What are the two types of surgeries?
1) Valvuloplasty and anticoagulation
2) Synthetic vs. xenograft valvuloplasty
1) Where are congenital ASDs (atrial septal defects)?
2) What percent of the population has a small one?
3) What happens with a larger ASD?
1) Congenital foramen ovale defect
2) ~15-25% population has small ASD
3) Larger ASD ~left to right or right to left shunt
1) What are congenital VSDs (ventricular septal defects) a cause of?
2) Where does blood go?
3) What are some causes of non-congenital VSDs?
1) Major cause of congenital heart defects
2) Left to right
3) Pulmonary HTN and RHF
What are two types of septal defects of the heart?
ASD and VSD
True or false: pulmonary circulation is minimal in fetal circulation
True
What path does blood take in fetal circulation?
-Shunts blood from right side of heart to left or general circulation
-Blood flows through the ductus arteriosis to the left side
-Foramen ovale connects left and right atria
Why is resistance so high in fetal pulmonary circulation?
Lungs are filled with fluid
What 2 parts of fetal circulation becomes no longer patent or open shortly after birth?
Ductus arteriosus (becomes ligamentous arteriosus) and foramen ovale
What system is bypassed in fetal circulation?
Hepatic portal system
