Passage between the adjoining edges of endothelial cells. All of the above are valid mechanisms. All of the above. Lymph capillaries are not found in neural tissue. Lymph capillaries are not found in bone marrow.
Lymph capillaries originate blindly in the tissue from which lymph is collected.
Like blood capillaries, lymph capillaries have a well-defined, continuous epithelium. None of the above is false. They may have a second layer of smooth muscle, within the adventitia. They may contain capillaries within the subendothelial connective tissue. The adventitial layer is the thickest of their tunics.