1 Ghrelin is a fast-acting hormone that plays a vital role in meal initiation and contributes to weight gain. 2  Leptin mediates long-term regulation of energy balance and suppresses food intake, thereby inducing weight loss.  Both hormones can be controlled naturally, primarily though exercise and stress management.
Surgical retractors. A retractor is a surgical instrument with which a surgeon can either actively separate the edges of a surgical incision or wound, or can hold back underlying organs and tissues, so that body parts under the incision may be accessed. The two are each available in many shapes, sizes, and styles.
retractor. 1  a person or thing that retracts. 2  Anatomy. a muscle that retracts an organ or protruded part. 3  Surgery. an instrument or appliance for drawing back an impeding part, as the edge of an incision. 4  a mechanism, device, or the like that regulates retraction: to adjust the retractor on a seat belt.