The Heart!

Some information regarding The Heart (doo doo doooooo!):

There should always be 5-6 liters of blood in the human body

Gross anatomy
The heart wall consists of 3 different tissues:
Epicardium - the surface of the heart
Myocardium - contractile muscles of the heart
    Cardiocytes
Endocardium - internal lining, simple squamous epithelium

Heart valves
Ensure one-way flow of blood
Consist of 2 or 3 cusps

Tricuspid valve - between right atrium and right ventricle
Bicuspid (Mitral) valve - between left atrium and left ventricle
    Chordae tendineae - 'cords of tendon'
    Papillary muscles - stabilize heart valves
Pulmonary semilunar valve - between systemic circuit and right atrium
Aortic semilunar valve - between left ventricle and aorta
Cardiac Conduction System
75 bpm on average in a resting adult
Myogenic - muscle cell, generates electricity
Autorhythmic - creates electricity while ignoring brain

Conduction system consists of modified cardiocytes

Sinoatrial (SA) node - group of myogenic cells
Atrioventricular (AV) node
AV bundles
    Left and right bundle branches
    Moderator band of R. ventricle
Purkinje fibers - fingerlike projections into ventricles

Cardiac muscle
Striated, but short, thick and branched
Fibers contain only one centrally placed nucleus
Cardiocytes are joined end to end by intercalated discs - allows cells to communicate

I liked this picture lol