Comparative Test 4 (C3)

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Comparative Test 4 (C3)
2011-12-09 20:11:12
Comparative Anatomy

Comparative anatomy lecture test four.
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  1. in the evolution of the heart and arteries, amphibians loose branchial circulation at _____.
  2. In the evolution of heart and arteries, reptiles never show _____.
    branchial circulation
  3. What are the modifications of aortic arches in amphibians and reptiles?
    • Reduced in number
    • 3rd pair remains as part of internal carotids to the head.
    • 4th and somtimes 5th are systemic arches to the dorsal aorta and body.
    • 6th arch provides pulmonary arches to lungs.
  4. What are the heart modifications in amphibians and reptiles?
    • Blood returning from the body is seperated from that returning from the lungs by a completely divided atrium (Thus a three chambered heart).
    • Level of division of ventricle, conus arteriosus, and ventral aorta is variable (crocodilians have divided ventricles thus a four chambered heart)
    • Generally, venous and arterial blood are separated.
  5. Describe the aortic arches in birds and mammals.
    • Both retain third aortic arches as part of carotids.
    • 6th aortic arches form part of the pulmonary arteries.
    • Right fourth aortic arch becomes the systemic arch (Aorta) in birds, so the aorta of birds curves to the right.
    • Left fourth aortic arch becomes the systemic arch in mammals, so the aorta in mammals curves to the left.
  6. Both birds and mammals have completely divided hearts with _____ , but they evolved these independently.
    four chambers
  7. Describe the left and right side of the heart in birds and mammals.
    • Right side of the heart receives venous blood from the body and sends it to the lungs.
    • Left side receives blood from the lungs and sends it to the body.