NU 606 Exam 3: Chpt. 12, 13, 25, 26 Questions With Complete Solutions

what are the two layers of the pericardial sac correct answer: outer fibrous pericardium anchors the heart to diaphragm visceral pericardium (epicardium) has a serous membrane what is unique about cardiac muscle (myocardial fibers) correct answer: - no nerves are present intercalated discs at the junctions between fibers (they contain desmosomes, connections to prevent muscle cells from separating during contraction, and gap junctions, which permit ions to pass from cell to cell which facilitates rapid transmission of impulses what ensures that all muscle fibers of the two atria followed by the two ventricles contract together or shortly after as it were correct answer: gap junctions and desmosomes where does a conduction impulse start correct answer: all muscle cells can start it, but it usually originates in the sinoatrial node - the pacemaker what can alter the SA node impulses correct answer: autonomic nervous system fibers and circulating hormones such as epinephrine what is the only anatomical connection between atrial and ventricle conduction in the heart correct answer: AV node where does the cardiac electrical impulse go after the AV node correct answer: av bundle/ bundle of His, the right and left bundle branches, and the terminal purkinje network of fibers what stimulates ventricular contraction correct answer: terminal purkinje fibers? what does the P wave represent in an ECG correct answer: atrial depolarization what does the QRS wave represent in an ECG correct answer: depolarization of the ventricles - during that time it masks the effect of atrial repolarziation what does the T wave represent on an ECG correct answer: ventricular repolarization where is the cardiac control center and what does it do correct answer: medulla of the brain. responds to changes from the baroreceptors (which detect BP and are located in the aorta and carotid) . activate sympathetic nervous system or