UNIT II Lecture Notes Outline

UNIT II Lecture Notes Outline - UNIT II Lecture...

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UNIT II Lecture Notes (beginning where we left off in lecture before exam I) II. THE HEART (continued) (Chapter 18) A. Location B. Pericardial Sac (or parietal pericardium) 1. Fibrous Layer (fibrous pericardium) 2. Serous Layer (serous pericardium) a. Parietal pericardium b. Visceral pericardium pericardial cavity C. Structure of the Heart 1. The Wall a. Epicardium (or visceral pericardium) b. Myocardium c. Endocardium 2. The Chambers a. Two Atria ( pumps) b. Two Ventricles ( pumps) 3. Major Vessels of the Heart veins ---carry blood the heart arteries ---carry blood the heart red = blood blue = blood a. veins entering the right atrium - - - b. artery leaving the right ventricle - c. veins entering the left atrium - d. artery leaving the left ventricle - small thebesian veins empty into all chambers of the heart
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4. Heart Valves a. Atrioventricular (AV) Valves 1) Right AV Valve (tricuspid valve) 2) Left AV Valve (bicuspid or mitral valve) b. Semilunar Valves 1) Pulmonary Semilunar Valve in Right Vent. 2) Aortic Semilunar Valve in Left Vent. Cardiac Cycle Blood Flow through the Heart -blood flows from an area of pressure to an area of pressure. -the greater the volume of blood, the higher the pressure atrial press. > vent. press. ----AV valves open and blood goes into vents. vent. press. > atrial press. ---AV valves close (1 st heart sound; lub) vent. press. > arterial press.---semilunar valves open and blood leaves vents. arterial press. > vent. press.---semilunar valves close (2 nd heart sound; dup) now atrial press. > vent. press. once more and atrial press. forces the AV valves open agin and blood goes into vents. and another cycle begins 5. The Conductive System of the Heart a. SA Node (sinoatrial node) [ rhythm] b. Internodal Pathways c. AV Node (atrioventricular Node) - last portions of the atria to be depolarized - slowness due to: 1) AV nodal fibers are 2) fewer 3) more of cells in fibers [ rhythm]
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AV Bundle (Bundle of His) right and left bundle branches e. Purkinje Fibers f. Transmission of the cardiac impulse in the ventricular muscle 6. Control of Excitation and Conduction in the Heart 7. Abnormal Rhythms of the Heart a. Premature Contractions (ectopic foci) b. Heart Block e.g., atrioventricular block (very common) 1) Causes of Heart Block: - of AV junctional fiber - compression of AV bundle of scar tissue or calcified portion of heart - inflammation of AV bundle or fibers of AV junction - extreme stim. of heart by nerves 2) Types of Blocks: - 1 st degree block (incomplete heart block) prolonged interval (>0.20 sec.) - 2 nd degree block P-R interval 0.25-0.45 sec. (2:1, 3:1, 3:2 rhythm) - 3 rd degree block ( AV block) P waves completely dissociated from QRS-T complexes (atria at 100 beats/min and ventricles at 40 beats/min) c. Flutter and Fibrillation – low freq., coordinate contractions up to 200-300 beats/min. fibrillation –
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This note was uploaded on 02/13/2011 for the course BIOL 228 taught by Professor Marilynkoob during the Spring '10 term at Boise State.

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UNIT II Lecture Notes Outline - UNIT II Lecture...

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