neurohormonal short

Question 1

bainbridge reflex

Answer 1

when heart rate is low, increased stretch of atria by increased venous return activates sympathetic activity to SA node so increased HR

Question 2

why angina felt in throat and arm

Answer 2

• ischeamia means release of lactate, serotonin, bradykinin, histamine, adenosine. Causes vasodialtion
• activate chemo and mechanosensitive receptors of unmyelinated nerve cells in cardiac muscle and around coronary vessels
• these nerves travel along sympathetic afferent pathways into sympathetic ganglia of C7 to T4 so pain experienced in these dermatomes