Heart sounds are a result of a beating heart and resultant blood flow.

Heart murmurs are pathological noises that results from abnormal blood flow in the heart or blood vessels.

Turbulent blood flow is a result of stenotic (narrowed) valves or blood vessels.

Third heart sound is pathological in children but physiological in adults.

Extrasystole

Endocarditis

Cardiac tamponade

Aortic valve stenosis

Mitral stenosis

Monocytes

Basophils

Eosinophils

Neutrophils

Lymphocytes

Diastolic dysfunction

Arrhythmogenic right ventricular cardiomyopathy

Dilative cardiomyopathy

Restrictive cardiomyopathy

Hypertrophic cardiomyopathy

The cardiac cycle spreads along both atria through the gap junctions of the cardiac muscle fibers.

At the atrioventricular node slight delay of the electrical transmission occurs.

The bundle of His receives the action potential from the AV node.

The autorhythmic cells serve as a pacemaker to initiate the cardiac cycle.

The bundle of His conducts the action potential from the interventricular septum, down to the apex of the heart.

The heart regulates the amount of vasodilation or vasoconstriction of the coronary arteries.

During the ventricular systole, the subendocardial coronary vessels are compressed due to the high intra-artirial pressures.

If the posterior descending artery is supplied by the circumflex artery (CX), then the coronary circulation is termed as left-dominant.

The papillary muscles are attached with the mitral valve.

The majority of vasculature in the body constricts to norepinephrine.

When the left ventricle contracts, the left AV valve gets closed.

When the left ventricle relaxes, the aortic semilunar valve gets closed.

The left ventricle is smaller and its walls are thinner than those of the right ventricle.

The chordae tendineae are attached to papillary muscles at the opposite, bottom side of the right ventricle.

When the right ventricle relaxes, there is more pressure in the pulmonary trunk.

Nicotine

Angiotensin II

Epinephrine and norepinephrine

Antidiuretic hormone

Atrial natriuretic peptide

Afferent fibres carrying pain sensation run to the spinal cord.

During rest, the vagal tone is recessive.

Postganglionic fibres descend to the heart and form two plexuses.

The effect of autonomic nervous system on coronary artery and blood flow is a reciprocal.

Preganglionic sympathetic fibres ascend from the upper five thoracic segments of the spinal cord.

The heart is effectively a syncytium.

Few cardiac cells can contract without any signal from the nervous system.

The SA node generates electrical impulses.

The impulses are delayed for about 0.1s at bundle of His.

This entire cycle, a single heart beat, lasts about 0.8 seconds.

Vagal stimulation

Mild alkalemia

Sympathetic stimulation

Moderate warming

Thyroid hormones

Depolarisation propagates through cardiac muscle very sluggishly.

Temporary inactivation of certain ion channels helps heart in relaxation.

The action potentials of cardiac muscle are unusually sustained.

There is a substantial atrial to ventricular delay.

There is a coordinated contraction of ventricular cells.

Within the cell, Ca 2+ binds to troponin.

Rapid depolarization occurs when fast‐opening Na ⁺ channels in the sarcolemma open.

A plateau phase occurs during which K⁺ enters the cytosol of the muscle cell.

Repolarization occurs as K ⁺ channels open and K ⁺ diffuses out of the cell.

The refractory period of cardiac muscle is dramatically longer than that of the skeletal muscle.

Paracrines

Local chemical factors

Non-adgregenic, non-cholinergic autonomic nerves

Renal hormones

Epinephrine

Leukocytes can leave the blood stream.

Blood cells have epithelial origin.

Erythrocytes contribute about 43% of the total volume of the blood.

The blood platelets perform their functions exclusively in the blood stream.

Erythrocytes are the dominant cells in the blood.