QUESTIONS 121 



What is the function of the auricles? 



What variations in pressure are there in the auricles? 



Discuss the entrance of the blood into the auricles from the veins. 



Discuss the cause of the rhythmic activity of the heart. 



What is the "cardiac excitation wave"? 



Where does the contraction of the heart begin? 



What is the effect of tying a ligature about the auriculoventricular groove? 



What is the speed of the cardiac excitation wave? 



What is the latent period of the frog's heart muscle? 



What is the time value of the block of the heart's contraction? 



Describe the atrio ventricular bundle. 



W T hat is the cause of the block? Give evidence. 



What is meant by the refractory period of the heart beat? 



Define compensatory pause. 



What are the sources of the nerve fibers to the heart? Describe their 

 course. 



Discuss the effect of stimulation of the vagus on the heart beat. 



How does stimulation of the vagus affect a demarcation current from 

 the auricle? 



Discuss the end apparatus by means of which the vagi inhibit the heart. 



What is the effect of stimulation of the augmentor fibers on the heart 

 beat? 



Give the lengths of the latent periods of inhibition and acceleration. 



What evidence that afferent fibers run from the heart to the central 

 nervous system? 



Discuss the function and the effects of stimulation of the central cut end 

 of the depressor nerve. 



Are the vagi and depressor nerves continuously active? 



How do weak and strong stimulation of sensory nerves affect the heart? 



What effect has dilatation of the stomach on the heart? 



Discuss the situation and action of the cardio-mhibitory centre. 



Discuss the action of the accelerator centre. 



What is the peculiarity in the distribution of bloodvessels to the heart? 



What is an infarct? 



How does the anemia resulting from hemorrhage differ in its action from 

 that caused by ligating the coronary artery? 



How do the contractions of the heart favor the entrance of blood into 

 the coronary arteries? 



In what ways does the blood supply to the heart affect its beat? 



Discuss the constituents of the blood that cause the rhythmic activity 

 of the heart. 



How do the actions of potassium and calcium salts differ? 



What is Ringer's solution? 



What effect has carbon dioxide on the heart? 



Why does the blood move from the arteries to the veins? 



How is blood pressure measured? 



Describe a mercury manometer. 



Wliat is the form of blood pressure curves obtained from an artery? 



What is meant by mean blood pressure? 



What are the mean blood pressures in arteries, capillaries, and veins? 



What is the cause of the high pressures in the arteries? 



What are the causes of blood pressure in capillaries and veins? 



Why does the pressure decline from arteries to veins? 



Why is there no pulse in the veins? 



Discuss the action of subsidiary forces that aid the heart in circulation. 



What is the pulse? Its cause? 



How does the character of the pulse vary? 



