Cardiovascular - Anatomy + Physio Flashcards
Which coronary artery branches off the posterior aortic sinus?
Left coronary artery
Which coronary artery branches off the anterior aortic sinus?
Right coronary artery
What is the route of the left coronary artery?
LCA
1. Left Anterior Descending / Anterior Interventricular Artery (anterior)
–> Diagonal branches
2.** Left circumflex (posterior)**
—–> 3 Left Marginal Arteries
What is the route of the right coronary artery?
RCA
1. RCA comes down anterior (anterior)
–> Right marginal artery
2. Posterior inter-ventricular artery (posterior)
Where does the SAN artery branch off?
Right coronary artery
Which 2 arteries meet at the apex of the heart?
- Left Anterior Descending
- Posterior Interventricular Artery
Which artery supplies the inferior wall of the heart?
Left circumflex artery
Which artery supplies the antero-lateral wall of the heart?
Left Anterior Descending Artery
Distal - V3 + V4
Which artery supplies the antero-septal wall of the heart?
Left Anterior Descending Artery
Proximal - V1 + V2
What is right dominance of the heart?
Posterior descending artery supplied by the RCA
Most common
What is left dominance of the heart?
Posterior descending artery supplied by the LCA
Worst prognosis in MI - loss of anterior and posterior blood supply
What is co-dominance?
Posterior descending artery supplied by both the RCA and LCA
Best prognosis but least common
What is a myocardial bridge?
Myocardial muscle covering a major coronary artery
runs through the heart, only branches visible externally
What are the 3 things in the carotid sheath?
- Common carotid artery
- Internal jugular vein
- Vagus nerve
At what level of the spinal cord do the common carotids bifurcate into internal and external carotids?
C3-4
Level of the posterior hyoid bone
What level of the spinal cord do the phrenic nerve branch off?
Phrenic nerve branches off at C3,4,5
Comes down mediastinum, contributes to cardiac plexus and innervates the diaphragm
How does referred pain work in heart injury?
When heart injury - phrenic nerve sends afferent signals to CNS
Phrenic nerve originates at C3,4,5 - so CNS cannot localise the pain and instead gives response of pain in whole region
C3,4,5 also supplies shoulder, neck and jaw = referred pain in MI
What structures lie in the superior mediastinum?
Trachea
Oesophagus
Arch of aorta
SVC
Vagus and phrenic nerves
Left recurrent laryngeal nerve
At what point of the spinal cord is the mediastinum split into superior and inferior?
T4-5
Sternal Angle
What lies in the anterior inferior mediastinum?
Thymus
What structures lie in the middle inferior mediastinum?
Heart
Pericardium
Phrenic nerves
Ascending aorta
Pulmonary trunk
What structures lie in the posterior inferior mediastinum?
Oesophagus
Sympathetic chain
Azygous vein
Descending aorta
Vagus nerve
Thoracic duct
What is the relation of the left recurrent laryngeal nerve to the aortic branch?
LRLN heads behinds arch of aorta and loops around right sublavian artery to head back up to larynx
Left laryngeal nerve branches off the vagus nerve
LRLN provides motor innervation to the intrinsic muscles of the larynx
What are the 3 functions of the pericardium?
- Anchor heart to surrounding structures
- Protect heart from trauma, damage etcccc
- Prevent heart from overfilling and stretching
What are the layers of the heart?
From in to out
- Endocardium
- Myocardium
- Epicardium - Visceral layer of serous pericardium
- Pericardial cavity - Serous Fluid - prevent friction
- Parietal Layer of serous pericardium
- Fibrous pericardium - dense irregular connective tissue
Which vein is suitable for a central venous line to monitor central venous pressure and why?
Right Internal jugular vein
- Direct route to right atrium
- No valves
What vessel is best used for a autograft in a CABG?
Internal thoracic / internal mammory
Why is a thoracic artery better than a vein from the leg for autograft in a CABG?
Artery already adapted to carry high pressure blood so less likely to become dilated.
Can provide alternative source of blood supply - only have to change one side and leave the other intact
Do not have valves
Where is the coronary sinus located?
Posterior aspect of the heart
What does the coronary sinus drain into?
Right atrium
85% of venous drainage occurs via coronary sinus
What are the thesbian veins?
Smallest cardiac veins
Drain into the 4 chambers of the heart
Why is the blood in the left ventricle less saturated with oxygen than the blood it originally receives from the pulmonary veins?
Left ventricle receives blood from thesbian vein = mixing venous blood = physiological shunting
What is the vessel course of the arch of aorta?
Brachiocephalic trunk
- Right common carotid
- Right subclavian artery
Left common carotid
Left subclavian artery
Where does the azygous vein drain into?
Posteriorly in to inferior vena cava
What are aortic sinuses?
Small swelling in aortic artery
- Stops valves sticking to the aortic wall so they can still close
- Allows blood to pool in the sinuses after systole to allow valves to shut before flowing out arteries
What are the atrio-ventricular valves?
Left - Mitral/bicuspid
Right - Tricuspid
Between atria + ventricle - Closed at start of ventricular contraction