Neurogenous ischemia model in the frog interdigital swimming membrane

Cut the skin longitudinally with scissors on the posterior surface of the thigh along the groove containing the neurovascular bundle. Dissect the sciatic nerve and place a ligature beneath it but do not tie. Spread the swimming membrane over the round hole in the board fastening its ends with pins. Find an appropriate portion of the membrane rich in blood vessels and examine the circulation at low magnification (x10). Then tie the ligature tightly and cut the nerve above the ligature. Note the microcirculation changes correspondent to neuroparalytic arterial hyperemia. Then, tugging by the ligature and, in this way, exciting the peripheral end of the severed sciatic nerve, produce neurotonic ischaemia against the background of neuroparalitic arterial hyperemia.

3Answer the questions.

1. The organs of which animals are used to model microcirculatory disorders and why?

2. Which organ of the frog is used to model arterial hyperemia?

3. What test is performed on a frog for modeling arterial hyperemia?

4. Which organ is used to model venous hyperemia?

5. What test is performed on a frog for modeling venous hyperemia?

6. What parameters must be taken into consideration while observing microcirculatory changes?

7. Which organ is used to model neurogenous ischemia?

8. What test is performed on a frog for modeling neurogenous ischemia?

9. Why are animals’ organs used in experiments?