Anatomy of the heart 2

Question 1

What are the two parts of the interventricular septum?

Answer 1

Membranous and the muscular parts

Question 2

Describe the conducting system of the heart

Answer 2

Sinoatrial node spreads impulse through atrial tissue, causing atrial systole.
Then there is the AV pause as the impulse moves to the ventricles. Then impulse travels down the left and right bundle branches, along the moderator band to the papillary muscles and then up the purkinje fibres.

Question 3

What are the leads of a pacemaker in the heart?

Answer 3

Travelling through the superior vena cava into the right atrium, the 3 leads of a pacemaker reach the right atrium wall, right ventricle and the coronary sinus.

Question 4

Describe sympathetic stimulation of the heart

Answer 4

Causes an increase in HR via the cardiac nerves with ganglia in the sympathetic chain so postganglionic fibres cause cardioacceleration

Question 5

Describe parasympathetic stimulation of the heart

Answer 5

Causes a decrease in HR via the vagus nerve (NX) with preganglionic parasympathetic fibres synapsing in the cardiac plexus then parasympathetic postganglionic fibres cause cardioinhibition

Question 6

What is different about a left dominant heart?

Answer 6

Left coronary artery does weird loop and supplies the SA node

Question 7

What is different about a right dominant heart?

Answer 7

The circumflex artery supplies the AV node

Question 8

Why is there referred pain when you have a heart attack?

Answer 8

Heart supplied by T1-T5, pain felt in those dermatomes on the left hand side.