Question

Describe the events of a cardiac cycle based upon contracting and relaxation phases.

Describe the activity of each chamber during cardiac systole and cardiac diastole. Be able to relate the electrical activity of the heart (depolarization, repolarization) to the corresponding electrical activity depicted on a typical ECG/EKG tracing. Label and define the waves.

Trace the depolarization pathway through the intrinsic conduction system components. Compare and contrast cardiac and skeletal muscle contraction.

Answer 1

All activities of the heart through one complete heartbeat which includes one contraction and relaxation of both atria and ventricles is called a cardiac cycle.

A contraction ---> systole

A relaxation ---> diastole

Section 1 of question : events of a cardiac cycle based upon contracting and relaxation phases - explained in attached image 1

Section 2 of question : activity of each chamber during cardiac systole and cardiac diastole. - explained in attached image 2

Section 3 and 4 of questions : electrical activity of the heart (depolarization, repolarization) to the corresponding electrical activity depicted on a typical ECG/EKG tracing. Label and define the waves. - explained in attached image 3

Section 5 : Trace the depolarization pathway through the intrinsic conduction system components. - Explained in image 4

Section 6 : Compare and contrast cardiac and skeletal muscle contraction.: explained below

Cardiac muscle contraction Skeletal muscle contraction

• Involuntary contraction Voluntary contraction
• Self stimulating and impulse spreads from cell to cell non self stimulating as each muscle contraction controlled by pacemaker cells fibre is innervated with somatic motor neurons    .
• Rhythmic contraction Non-Rhythmic contraction
• Doesn't fatigue Fatigues easily
• Contract regulation by Acetylcholine+Norepinephrin Contract regulation by Acetylcholine