The heart is found in the ___ between the ___ and beneath the ___ .

The two upper chambers are ___ walled atria and ___ the heart. The two lower chambers are ___ walled ventricles and pump blood ___ the heart.

The walls of the heart are supplied with oxygenated blood via ___ .

The heart beat is ___ in its origin - a structure in the ___ called the ___ .

The heart's natural rhythm set by the pacemaker is about ___ bpm , however, conditions in our body can override this basic rate.

Nervous control of the heart is by ___ reaction and it receives impulses from a ___ centre in the hindbrain ( ___ ) via two nerves.

When secreted by the pacemaker, the hormone ___ causes an increase in the heart rate.