Coverings of the Heart-
Fibrous Pericardium- tough outer layer
Serous Pericardium- Inside of the pericardium has two layers with
pericardial fluid in the center
Structure of the Heart-
Epicardium- outer layer
Myocardium- thick contractile middle layer that compresses the heart cavities.
Endocardium- delicate inner layer (single layer of endothelial cells)
Atria- “receiving chamber”
Auricle- earlike flap protruding from each atrium
Ventricles- “pumping chambers” THICKER Myocardium
Valves of the Heart-
Atrioventricular valve (AV) Connected to papillary muscle by Chordae Tendineae
Tricuspid-right (Between Atria and Ventricles)
Bicuspid/Mitral- left (Between Atria and Ventricles)
Semilunar Valve (SL)-
Pulmonic Valve- Entrance of Pulmonary artery
Aortic Valve- Entrance of Aorta
Blood supply to the Heart-
Coronary arteries- left and right deliver blood to myocardial cells.
Branches from the ascending aorta
Cardiac Veins- drains into the right atrium.
Conduction in the heart-
SA Node (pacemaker) initiated
Bundle of his-
Nerve supply to the heart-
Sympathetic- increases stroke volume, hr, vasoconstriction
Parasympathetic- inhibits constriction
Arteries- Carry Blood AWAY from the Heart
Veins- Carry blood TOWARD the Heart. Reservoir blood.
Muscular artery- distributing
Arterioles- regulates BP
Metarterioles- between arterioles and capillaries
Capillaries- gas exchange occurs
True- precapillary sphincter....
Continuous caps- cont.....
Fenestrated- has holes to let protein etc. pass
Sinusoids- large. Porous.
Layers of Blood Vessels-
Tunica adventitia- outermost, in Art/Vein
Tunica media- middle in Art/Vein
Tunica intima- single layer capillaries
Endothelial cells- lining....
Collagen fibers- woven, keeps lumen vessel open....
Elastic fibers- protein... smooth- active tension....
Systemic circulation- leaving right vent. Returning to right atrium
Systemic arteries-arterial anastomosis- artery to artery
AV anastomoses- art to vein
Systemic veins- superior vena cava and inferior vena cava
Hepatic portal circulation- veins from organs filter to liver, then from liver
to inferior vena cava.
Pulmonary Circulation- Flow within the heart and Lungs
Two umbilical arteries- carry fetal blood to placenta....
Placenta- oxygen/substance exchange....
Umbilical vein- returns oxygenated blood from placenta to fetus, becomes
round ligament of the liver....
Ductus venosus- continuation of umbilical vein, drains to ivc, becomes
ligamentum yenosum of the liver....
Foramen ovale- opens in septum between atria, becomes fossa ovalis...
Ductus arteriosus- connects pulmonary artery with descending thoracic
Conduction- know each section and what it does
P wave- depolarization of the atria
QRS- depolarization of ventricles/rep of aria
T- re-polarization of ventricles...
Atrial systole- begins at p wave. Contraction of atria completes emptying out of
atria into ventricles.
Isovolumetric ventricular contraction- coincides with the R wave. First heart
sound. Start of ventricular systole and SL valve opening. AV closure
Ejection- coincides with T wave. SL valves open.
Isometric ventricular relaxation- second heart sound is heard. All valves closed.
Passive ventricular filling- pressure builds until AV valve opens.
systolic- first- closing AV valve
diastolic-second sound- closing of SL....
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