Indicate whether the following statements are true or false :
(i) Fish heart contains only oxygenated blood.
(ii) Closure of A-V valves produces the second heart sound.
(iii) The vagus nerve retards the heart rate.
(iv) The S-A node is the pacemaker of the heart.
(v) Columnae carneae occur in the auricles.
(vi) Purkinje fibres are nerve fibres present in the heart wall.

Consider the following four statements (i)-(iv) and select the correct option (i) Fish heart contains only oxygenated blood (ii) Closure of A-V valves produces the second heart sound (iii) The vascular connection between the digestive track and kidney is called hepatic portal system (iv) Purkinje fibres are nerve fibres present in the heart wall.

Consider the following four statements (i)-(iv) and select the correct option (i) Fish heart contains only oxygenated blood (ii) Closure of A-V valves produces the second heart sound (iii) The vascular connection between the digestive track and kidney is called hepatic portal system (iv) Purkinje fibres are nerve fibres present in the heart wall.

Indicate whether the following statements are true of false : (a) Both auricles of amphibian heart open into the same ventricle. (b) Prawn's heart carries only oxygenated blood. (c ) Purkinje fibres are nerve fibres supplying the ventricular muscles. (d) The first heart sound results from a closure of semilunar valves. (e ) The vagus nerve reduces the heart rate. (f) The A-V node normally initiates the cardiac impulse. (g) Semilunar valves open during the ventricular diastole.

Read the following statements carefully (i) In fishes, the heart pumps out deoxygenated blood which is oxygenated by the gills and supplied to the body parts from where deoxygenated blood is returned to the heart. (ii) The openings of the right and the left ventricle into pulmonary artery and aorta respectively are provided with the mitral valves. (iii) The nodal musculature has the ability to generate action potential without any external stimuli, i,e., it is autoexcitable. (iv) The T-wave of ECG represents depolarisation of the ventricles. Which of the above four statements are incorrect?

Go through the following statements, (i) The stroke volume multiplied by heart rate gives the cardiac output. (ii) The second heart sound is associated with the closure of semilunar valves (iii) Heart failure is the same as cardiac arrest or a heart attack. Which of these are correct ?

Go through the following statements, (i) The stroke volume multiplied by heart rate gives the cardiac output. (ii) The second heart sound is associated with the closure of semilunar valves (iii) Heart failure is the same as cardiac arrest or a heart attack. Which of these are correct ?

Go through the following statements, (i) The stroke volume multiplied by heart rate gives the cardiac output. (ii) The second heart sound is associated with the closure of semilunar valves (iii) Heart failure is the same as cardiac arrest or a heart attack. Which of these are correct ?

Go through the following statements, (i) The stroke volume multiplied by heart rate gives the cardiac output. (ii) The second heart sound is associated with the closure of semilunar valves (iii) Heart failure is the same as cardiac arrest or a heart attack. Which of these are correct ?

Which sequence of events best represents the conduction of an impulse through the heart? (i) Sinoatrial node (ii) Atrioventricular node (iii) Purkinje fibres (iv) Bundle of His