Question

In connection with circulatory system, valves are present

• A. Not only in heart and blood vessels of vertebrates and invertebrates but in vertebrate lymphatics as well
• B. Vertebrate heart only
• C. Vertebrate and invertebrate hearts only
• D. Vertebrate hearts, invertebrate hearts and their blood vessels

Answer 1

The correct option is A Not only in heart and blood vessels of vertebrates and invertebrates but in vertebrate lymphatics as well

Lymph vessels are thin walled, valved structures that carry lymph away from the tissues to lymph nodes and eventually to either the right lymphatic duct or the thoracic duct. These vessels drain into the right and left subclavian veins respectively. Valves prevent the back flow of the lymph from the lymph nodes back to the tissues.