Esdin LS 2 Lec 8 Cardio

Activities electrode on one ankle extracellular

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Unformatted text preview: tial Gap junction Intercalated disc Electrocardiogram old way electrodes on wrists recording summation of electrical activities electrode on one ankle extracellular Recording the electrical activities of the heart 10 4/21/13 Electrocardiogram not AP, sum of all activites +1 ventricular depolarization contracting, (QRS) more muscle mass in ventricular repolarization ventricles relaxation atrial depolarization when atria contract Electrocardiogram non-invasive technique QRS QRS QRS QRS QRS one heart cycle 11 4/21/13 ECG QRS complex contracts mV atrial activity T wave P wave SA AV tricuspid and bicuspid valves SA node AV nodal delay Signals travel through bundle open of His reaching atria contract, blood to ventricles the apex ventricles contracting Purkinje fibers Blood Vessels •  Form closed circuit tubes that carry blood from the heart to cells and back to the heart •  Arteries, arterioles, capillaries, venules, and veins 12 4/21/13 Arteries highly elastic and expand in size since they have highest pressure and don't wanna pop •  Strong elastic vessels that carry blood away from the heart •  Branch into smaller arterioles lumen: cavity where blood is found Veins •  Carry blood back to the heart •  Have thinner walls than arteries •  Small branches are called venules 13 4/21/13 tunica intima: very small layer want minimal friction Layers of Arteries and Veins adventitia •  Tunica externa –  Connective tissue with elastic and collagen fibers •  Tunica media highest amount found in arteries   • accommodates activities of the body (dilating and contracting) (ie. if not using legs, less blood flow there) –  Made of smooth muscles –  Mediate vasoconstriction and vasodilation increase in bloodflow Tunica interna –  Made of simple squamous epithelium (endothelium) –  Provide smooth surface for blood to pass through inner layer, very smooth, minimizes friction highest pressure in the arteries (nearest the heart) Arteries & Veins Lumen Tunica intima Tunica media Valve Tunica externa Artery Arteriole Capillaries Venule lowest pressure, less smooth muscles, blood back to heart, have valves inside to make sure the blood keeps pumping unidirectionally Vein brings blood to heart carried blood from heart small arteries, still have 3 layers, sight of exchange, most abundant blood vessels, no tunica externa/media 14 4/21/13 Arteries & Veins Rest (Tone) vasoconstriction vasodilation Capillaries diffusio...
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