Anatomy of the heart and major vessels Flashcards
What are the three layers of the pericardium
Fibrous, parietal and visceral
Describe the anatomy of the tricuspid valve
The tricuspid valve separates the RA and the right ventricle (RV): the three cusps (septal, inferior, anterior) are attached to the fibrous atrioventricular (A-V) ring.
The free edges and inferior surfaces are attached by chordae tendinae to papillary muscles in the RV wall.
Describe the anatomy of the mitral valve
The mitral valve consists of two asymmetrical leaflets attached to the fibrous A-V ring (anterior, posterior); the larger anterior leaflet shares the same attachment as the non-coronary cusp of the aortic valve.
The valve leaflets are attached to the chordae tendinae, papillary muscles and the LV myocardium.
What is the anatomical difference of the outflow tracts
They are smooth walled and lack trabeculae, unlike the rest of the ventricles
Describe the conduction system of the heart
Sinoatrial node generates an action potential, which conducts across the atria in a synchronus fashion.
(note anterior, middle and posterior internodal tracts exist but contraction across the atria is usually non specific)
The Atrioventricular node slows the action potential. The atria and ventricles are separated by fibrous AV rings which electrically insulate them. Therefore the AV node is the only electrical link.
The action potential is potentiated down the bundle of HIS via the left and right bundle branches.
Note some people have accessory pathways which can be responsible for AVNRT.
Describe the anatomy of the coronary arteries
The coronary aa’s arise from the aortic sinus.
The right coronary aa arises from the anterior aortic sinus.
The right marginal artery arises from the right coronary artery.
The left coronary artery arises from the left posterior aortic sinus.
It divides into the left anterior descending (LAD/interventricular) and circumflex arteries; the latter give rise to obtuse marginal arteries.
The LAD arteries give off one or more diagonal branches and septal perforating branches.
Where does the posterior descending aa arise
In 85% of people it arises from the right coronary aa in the posterior intraventricular groove
In 15% of people it arises from the left coronary aa in the posterior intraventricular groove
Describe the coronary venous system
Coronary veins accompany the coronary arteries and open into the right atrium.
The majority (75%) of the venous blood drains via the coronary sinus.
The principle tributaries of the coronary sinus are the great, small, middle and posterior LV cardiac veins.
The anterior cardiac veins drain the anterior part of the RV directly to the RA.
Small veins drain directly into the cardiac chambers (thebesian veins).
Describe the parasympathetic nn supply of the heart and its effects
The vagus nn and recurrent laryngeal nn supply the parasympathetic nn stimulation to the heart via the deep and superficial cardiac plexus.
Post ganglionic nn fibres pass to the SA and AV nodes.
Causing:
reduced rate
reduced contraction
coronary artery constriction
Describe the sympathetic nn supply of the heart
The sympathetic supply originates from the lateral horns of the spinal cord (T1-4).
Post-ganglionic fibres arise from the three cervical ganglia and upper thoracic sympathetic ganglia.
Causes:
Increased rate
Increased contraction
Coronary aa dilation
Describe the anatomy of the jugular vein from its origin
Starts at the base of the skull from the jugular foramen.
It is enclosed within the carotid sheath with the internal carotid aa and vagus nn.
It is usually lateral to the aa.
It joins the subclavian behind the clavicle to become the brarchiocephalic vein.
Describe the anatomy of the subclavian vein
The subclavian vein is a continuation of the axillary vein.
It joins the internal jugular vein to form the brachiocephalic vein behind the sternoclavicular joint.
The subclavian vein receives the thoracic duct on the left side.
The subclavian vein passes over the first rib and lies posterior to the clavicle.
Describe the location of the structures in the femoral triangle.
The femoral triangle is made up of the:
Inguinal ligament (superior border)
Adductor longus muscle (medial border)
Sartorius (lateral border)
The femoral aa is located at the mid point between the ASIS and pubic symphysis.
Vein Artery Nerve (medial to lateral)
