Cardiovascular System The Heart Functions of the Heart Size, Shape, Location of the Heart

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Cardiovascular System The Heart Functions of the Heart Size, Shape, Location of the Heart

Scott, Randy, Host has reference to this Academic Journal, PHwiki organized this Journal Cardiovascular System The Heart Functions of the Heart Generating blood pressure Routing blood Heart separates pulmonary in addition to systemic circulations Ensuring one-way blood flow Heart valves ensure one-way flow Regulating blood supply Changes in contraction rate in addition to as long as ce match blood delivery to changing metabolic needs Size, Shape, Location of the Heart Size of a closed fist Shape Apex: Blunt rounded point of cone Base: Flat part at opposite of end of cone Located in thoracic cavity in mediastinum

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Heart Cross Section Pericardium Heart Wall Three layers of tissue Epicardium: This serous membrane of smooth outer surface of heart Myocardium: Middle layer composed of cardiac muscle cell in addition to responsibility as long as heart contracting Endocardium: Smooth inner surface of heart chambers

Heart Wall External Anatomy Four chambers 2 atria 2 ventricles Auricles Major veins Superior vena cava Pulmonary veins Major arteries Aorta Pulmonary trunk External Anatomy

Coronary Circulation Heart Valves Atrioventricular Tricuspid Bicuspid or mitral Semilunar Aortic Pulmonary Prevent blood from flowing back Heart Valves

Function of the Heart Valves Blood Flow Through Heart Systemic in addition to Pulmonary Circulation

Heart Skeleton Consists of plate of fibrous connective tissue between atria in addition to ventricles Fibrous rings around valves to support Serves as electrical insulation between atria in addition to ventricles Provides site as long as muscle attachment Cardiac Muscle Elongated, branching cells containing 1-2 centrally located nuclei Contains actin in addition to myosin myofilaments Intercalated disks: Specialized cell-cell contacts Desmosomes hold cells together in addition to gap junctions allow action potentials Electrically, cardiac muscle behaves as single unit Conducting System of Heart

Electrical Properties Resting membrane potential (RMP) present Action potentials Rapid depolarization followed by rapid, partial early repolarization. Prolonged period of slow repolarization which is plateau phase in addition to a rapid final repolarization phase Voltage-gated channels Action Potentials in Skeletal in addition to Cardiac Muscle SA Node Action Potential

Refractory Period Absolute: Cardiac muscle cell completely insensitive to further stimulation Relative: Cell exhibits reduced sensitivity to additional stimulation Long refractory period prevents tetanic contractions Electrocardiogram Action potentials through myocardium during cardiac cycle produces electric currents than can be measured Pattern P wave Atria depolarization QRS complex Ventricle depolarization Atria repolarization T wave: Ventricle repolarization Cardiac Arrhythmias Tachycardia: Heart rate in excess of 100bpm Bradycardia: Heart rate less than 60 bpm Sinus arrhythmia: Heart rate varies 5% during respiratory cycle in addition to up to 30% during deep respiration Premature atrial contractions: Occasional shortened intervals between one contraction in addition to succeeding, frequently occurs in healthy people

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Alterations in Electrocardiogram Cardiac Cycle Heart is two pumps that work together, right in addition to left half Repetitive contraction (systole) in addition to relaxation (diastole) of heart chambers Blood moves through circulatory system from areas of higher to lower pressure. Contraction of heart produces the pressure Cardiac Cycle

Events during Cardiac Cycle Heart Sounds First heart sound or “lubb” Atrioventricular valves in addition to surrounding fluid vibrations as valves close at beginning of ventricular systole Second heart sound or “dupp” Results from closure of aortic in addition to pulmonary semilunar valves at beginning of ventricular diastole, lasts longer Third heart sound (occasional) Caused by turbulent blood flow into ventricles in addition to detected near end of first one-third of diastole Location of Heart Valves

Chemoreceptor Reflex-pH Effects of Aging on the Heart Gradual changes in heart function, minor under resting condition, more significant during exercise Hypertrophy of left ventricle Maximum heart rate decreases Increased tendency as long as valves to function abnormally in addition to arrhythmias to occur Increased oxygen consumption required to pump same amount of blood

Scott, Randy Host

Scott, Randy is from United States and they belong to Alabama Stories – Alabama Public Television and they are from  Montgomery, United States got related to this Particular Journal. and Scott, Randy deal with the subjects like Features/Lifestyle; Human Interest; Local News; Regional News

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