Select true statements:
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heart muscle cells are interconnected by permeable intercalated disks, thereby forming a syncytium (Y)
sinoatrial (SA) node is cardiac pacemaker (Y)
inotropy is ability of the heart to respond only to signals of a certain intensity (N)
signals arising in the SA node spread in ventricles from endocardium to epicardium and from base to apex (N)
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SA node cells have a constant value of a resting membrane potential (N)
ventricular rhythm has a frequency of approximately 50/min (N)
plateau phase of the action potential is determined by slow influx of sodium cations (N)
ECG lead II and III can be used for diagnosis of pathological processes on the inferior wall of the heart (Y)
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ECG leads V5 and V6 detect processes on the anterolateral wall of the left ventricle (Y)
PQ interval informs about duration of conduction from heart atria to ventricles (Y)
QRS complex is an image of depolarization of ventricular cardiomyocytes (Y)
mitral valve closes at the end of ventricular systole (N)
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ejection fraction of a healthy human heart is 35-45 % (N)
afterload is a parameter describing resistance against blood flow (Y)
plasma glucose is the main energy source of healthy human heart (N)
production of natriuretic peptides in heart grows with increased wall stress in walls of atria and ventricles (Y)
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the greatest decrease in blood pressure occurs in capillaries (N)
veins contain the highest amount of blood from the whole blood circulation (Y)
turbulent flow predominates in the majority of blood vessels under physiological conditions (N)
parabolic profile of velocities of the individual layers of the blood flow is typical for laminar flow (Y)
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blood flow through the vessel increases with the fourth power of the radius (Y)
mean arterial blood pressure in systemic circulation reaches approximately 93 mm Hg, in pulmonary artery is about 15 mm Hg (Y)
about 5 % of resting cardiac output is used for brain circulation (N)
oxygen causes vasodilation of blood vessels in the brain (N)
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blood supply to the heart is not continuous – increases during systole and decreases during diastole (N)
β2-adrenergic receptors cause vasodilation in the coronary circulation (Y)
hypoxia and increased partial pressure of carbon dioxide cause vasoconstriction in the pulmonary circulation (Y)
kidneys receive 25% of total cardiac output (Y)
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myogenic autoregulation requires innervation of smooth muscle in blood vessel walls by spinal α-motor neurons (N)
nitric oxide produced by endothelial cells is a highly potent vasodilator (Y)
angiotensin II induces generalized vasoconstriction (Y)
changes in the partial pressure of carbon dioxide are the main signal for chemoreceptors in the medulla oblongata (Y)
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movement through the capillary wall is determined by four forces: capillary and interstitial hydrostatic pressure, colloid-osmotic pressure of plasma and colloid-osmotic pressure of interstitial fluid (Y)
net driving force of Starling forces is at the venular end directed inside the capillary (Y)
central venous pressure reflects the end-diastolic pressure in the left ventricle (N)
in the fetal circulation most of blood from the right ventricle flows to the pulmonary circulation (N)
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myocardial infarction can be diagnosed on ECG by ST segment elevation and by pathological Q waves (Y)
diagnosis of myocardial infarction is based on the determination of plasma levels of troponin T and glycogen phosphorylase (N)
regurgitation of heart valves leads to a pressure overload of heart compartment located after the valve (N)
markers of heart failure are natriuretic peptides (e.g. BNP) (Y)
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bradycardia is defined as a decrease in heart rate below 60 beats per minute (Y)
ventricular fibrilation is less severe than atrial fibrillation (N)
hyperkalemia leads to lower negativity of the resting membrane potential, which could result in asystole (Y)
most cases of hypertension have a diagnosable organic cause (N)
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diagnosis of hypertension is based on repeatedly measured increase of blood pressure ≥ 140/90 mmHg (Y)
tumors of adrenal cortex and adrenal medulla can cause secondary hypertension (Y)
edema is caused by an accumulation of insteritial fluid (Y)
obstruction of lymphatic vessels by tumor cells may cause an edema (Y)