Fig. 4.1 is a photomicrograph showing a human blood smear. Identify the cells marked A and B in Fig. 4.1.
Table 4.1 lists components that are present in both blood and lymph. Fill in Table 4.1 to show whether each component has a higher, lower or the same concentration in lymph than in blood from the aorta. You may use higher, lower or same once, several times or not at all.
A pathogen infecting the body is associated with a rise in the protein concentration of lymph. Suggest an explanation for this increase in protein concentration.
Describe the function of the sinoatrial node (SAN).
In a normal heart, the atrioventricular node (AVN) is the only route by which electrical impulses pass from the atria to the ventricles. The bundle of Kent is a structure present in the heart in a small number of people. Some electrical impulses bypass the AVN and go directly from the atria to the ventricles via the bundle of Kent. Suggest and explain the effects that having the bundle of Kent may have on heart rate.