Chemical Messengers 3. Hormones â¢Longârange messengersâ¢Secreted into blood by endocrine glands in response to appropriate signalâ¢Exert effect on target cells some distance away from release site 4.hemical Messengers 3. Hormones â¢Longârange messengersâ¢Secreted into blood by endocrine glands in response to appropriate signalâ¢Exert effect on target cells some distance away from release site 4.
Scale box in millimeters. Vesicular texture is a volcanic rock texture characterized by a rock being pitted with many cavities (known as vesicles) at its surface and inside.
Vesicles play many roles within a cell. Since vesicles are composed of a lipid bilayer, they can have a completely self-contained environment that is different from the inside of the cell. There are essentially four types of vesicles used by cells. They are vacuoles, lysosomes, transport vesicles, and secretory vesicles.