What would happen if there is failure of receiving the atrial impulse by the ventricles or completely independent contraction of the atria and the ventricles ?
A - Ventricular escape
B - Stokes - Adams syndrome
C - Irregularity in heart rhythm
D - Arteriosclerosis

Read the following statements and find out the incorrect statements. a. Heart is situated in the thoracic cavity, is between the two lungs, slightly tilted to the right. b. Heart has the size of a clenched fist. (c ) Heart is protected by double walled membranous bag, pericardium, enclosed the pericardial fluid. d. Human heart has four chambers, two relatively larger upper chambers called atria and two smaller lower chambers called ventricles. e. A thick muscular wall called the inter-atrial septum separtes the right and the left atria, whereas a thinwalled, the inter-ventricular septum, separtes the left and right ventricles.

Explain the following : (a) Why does the atrial systole normally precedes the ventricular systole ? (b) Why is S-A node called the pacemaker of the heart ? (c ) Why does the ventricle relax as a closed chamber in the early phase of its diastole ? (d) Why is there no mixing of deoxygenated and oxgenated blood in mammalian heart ? (e ) Why can you palpate the pulse on an artery in each heart beat ? (f) Why does the lymph contain much less proteins than the plasma ? (g) Why does the ventricle contract as a closed chamber in the early phase of its systole ? (h) Why is the closed circulatory system more efficient than the open one ? (i) Why does the left ventricle has a thicker wall than the right ventricle ?

a. SAN generates as action potential which stimulates atrial systole. b. ECG is an electrical representation of the graphical activity of the heart during a cardiac cycle. c. The cardiac output of a normal man will be much lesser than an athlete. d. The wall of right ventricle is much thicker than the left ventricle e. In pisces the two separate circulatory pathways are present, hence they have double circulation. f. The clsoed circulatory pattern is considered to be more advantageous than open circulatory pattern. g. Glucose is absorbed by simple diffusion through lymph in lacteales present in the intestinal villi. h. The SAN can generate the maximum number of action potential i.e. 140-150 mi n^(-1) in neonates, and is responsible for initiation and maintenance of the rhythmic contractile activity of the heart. i. Angina can occur in any age but more common among the neonates and infants. j. heart failure is sometimes called congestive heart failure because congestion of the blood vessels is one of the main symptoms of this disease.

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.

mark the true and false statements a. SAN generates as action potential which stimulates atrial systole. b. ECG is an electrical representation of the graphical activity of the heart during a cardiac cycle. c. The cardiac output of a normal man will be much lesser than an athlete. d. The wall of right ventricle is much thicker than the left ventricle e. In pisces the two separate circulatory pathways are present, hence they have double circulation. f. The clsoed circulatory pattern is considered to be more advantageous than open circulatory pattern. g. Glucose is absorbed by simple diffusion through lymph in lacteales present in the intestinal villi. h. The SAN can generate the maximum number of action potential i.e. 140-150 mi n^(-1) in neonates, and is responsible for initiation and maintenance of the rhythmic contractile activity of the heart. i. Angina can occur in any age but more common among the neonates and infants. j. heart failure is sometimes called congestive heart failure because congestion of the blood vessels is one of the main symptoms of this disease.

a. Amphibians and reptiles have a 3 chambered heart with ___ atria and ___ventricle. b. Heart is ___ derived organ and protected by a double walled membranous bag called ____ c. The opening between right Atrium and Right ventricle is guarded by a valve formed of ___ muscular flaps, the ___ valve. d. The wall of ventricle is ____ than atria. e. SAN can generate the maximum number of action potential i.e., ____ mi n^(-1) . therefore it is called _____ f. Atrial systole increases the flow of blood into the ventricles by about ____ percent. g. In ____ all the four chambers of the heart are in a relax state. h. The ____ wave represents the depolarisation of the atria. i. A system of blood vessels is present in our body exclusively for the circulation of blood to and from the cardiac musculature called _____ j. PNA ____ the rate of heart beat and ______