Applied Anatomy of the Heart Flashcards
what are the borders of the heart
- Upper right 3rd costal cartilage
- Upper left 2nd costal cartilage
- Lower right 6th costal cartilage
- Lower left 5th intercostal space, midclavicular line
what is the cardiac plexus made out of
- vagus nerve - decreases the heart rate
- sympathetic nerves - increases the heart rate
- general visceral afferent nerves
describe the pathway of the vagus nerve
CNX comes from the medulla runs down into the neck into the thorax and then into the cardiac plexus, gives off small branches which feed into the SAN
describe the pathway of the sympathetic nerves
from T1-T5 spinal cord levels, go to the sympathetic chain in then into the sympatheic chain ganglia then into the cardiac plexus, acts on the SAN to increase the rate of firing
where does sympathetic fibres enter the spinal cord between
T1-T5
where do the general visceral afferents enter the spinal cord and why is this important
T1 and T5 levels
- At these levels somatic afferents also enter the spinal cord
- Here they synapse with an interneuron and travel in the spinal cord to reach the brain
- The brain is unable to distinguish between visceral and somatic sensation and so pain is experienced within the somatic region
what is the right coronary artery divided in to
- Right coronary arteries – divides into the PDA and marginal branch
what is the left coronary artery divided in to
- Left coronary arteries – divides into the circumflex, left marginal branch of circumflex and LAD
what is the difference in appearance of the right and left coronary artery in an angiograph
RCA always looks C shape as it loops around the heart whereas LCA does not
LCA has three branches which you can see on the angiograph, it looks M shaped, easier to look at the LCA as all the arteries are going towards the apex of the heart
describe the blood supply to the conduction system
- RCA supplies the SA node
- The RCA supplies the AV node
- The interventricular descending arteries supply the bundle branches
what is the difference between right and left side dominance
- Right dominant heart – gives of PDA
- Left dominant – circumflex gives of PDA (only 30% of population)
what happens when there is bundle branch block
- Impulse travels through mycotyes – slows the impulse speed
- Prolongs QRS
- Loss of ventricular synchrony
where are the most common places that cause a myocardial infraction
- LAD
- RCA
- Circumflex
how do you do a coronary artery bypass
- take the great saphenous vein from the leg
- can sometimes use the internal thoracic mammary artery instead
what does an ECG do
- records the electrical activity to the heart