Distribution of ghrelin-ip cells in the lungs of the African ostrich. A, ghrelin-ip cells (arrows) were found within the lung; B, ghrelin-ip cells (arrows) within the tertiary bronchus mucosal epithelial cells; C, ghrelin-ip cells within the respiratory capillary epithelial cells (↑) and macrophage (↑↑); D, the control sections were negative. TB, tertiary bronchus; RC, respiratory capillary; IT, interstitial tissue. Scale bar: A and D=100 μm; B and C= 50 μm.