Heart

around the heart

Pericardium

allowes heart to beat without friction, provides room to expand, yet resists excessive expansion

anchored to diaphragm inferiorly and sternum anteriorly

Fibrous Pericardium

outer wall, not attached to heart

Serous Pericardium

Parietal layer

lines fibrous pericardium

Visceral Layer (Epicardium)

covers heart surface

Pericardial cavity

space filled with pericardial fluid

Percarditis

painful inflammation of membranes, can put dangerous pressure on heart

Heart Wall

Endocardium

Adipose in thick layer in some places

Coronary blood vessels travel thru this layer

smooth inner lining of heart and blood vessels

covers valve surfaces and is continuous with endothelium of blood vessels

Myocardium

layer of cardiac muscle

spirals around heart producing wringing motion, vortex of heart

fibrous skeleton of the heart, framework of collagenous and elastic fibers

structural support and attachment for cardiac muscle and anchor for valve tissue

electrical insulation between atria and ventricles, important in timing and coordination of contractile activity

double-walled sac that encloses the heart

Coronary Circulation

5% of blood pumped by heart is pumped to the heart itself

click to edit

250 mL of blood per minute

needs abundant O2 and nutrients

features I am less familar with

4 Valves

between R/L atria and their R/L ventricle (respectively)

Atrioventricular valves

each ventricle and its great arteries

Tricuspid

Semilunar valves

Pulmonary Valve

opening between right ventricle into pulmonary trunk

Aortic Valve

opening between left ventricle into Aorta

Bicuspid

Chordanae Tendonae

Trabecula Carnae

Papillary Musles

2 main types of Heart Cells

1%

Pacemaker Cells

99%

Contractile Cells

Electrophysiology

Voltage

difference in electrical potential between 2 points

membrane potential

voltage difference across membranes of all cells

resting membrane potential

membrane potential of excitable cell at rest (not stimulated) averages between -60 and -90 mV

difference in concentration of ions across plasma membrane

electrical signature

Rapid Depolarization due to Na+ inflow

Plateau due to Ca2+ inflow when voltage gated slow Ca2+ channels open and K+ outflow when some K+ channels open

Repolarization from closure of Ca2+ channels and K+ outflow as more K+ channels open

allows for refilling of heart chambers

electrical signature

Pacemaker potential - slow depolarization is due to both opening of Na+ channels and closing of K+ channels

Depolarization - begins when pacemaker potential reaches threshold, then Ca2+ influx thru Ca2+ channels

Repolarization - Ca2+ channels inactivating, K+ channels opening allowing K+ efflux and return to most negative voltage

ECG

Electrocardiogram

Dysrhythmia or arrhythmia

disturbance in electrical rhythm)

Bradycardia

less than 60 bpm

Tachycardia

more than 100 bpm

atrial fibrilation

not as serious, p wave wonky

ventrical fibriliation

very serious, life-threatening, must treat with defibrilator