upâ¢stream. 1. toward or in the higher part of a stream; against the current. 2. directed or situated upstream. 3. against or opposite to the direction of transcription, translation, or synthesis of a DNA, RNA, or protein molecule.dv. 1. Toward or closer to the source of a stream; in the direction opposite to that of the current: paddling upstream. 2. At an earlier point in a production process or supply chain. adj.
Positive feedback mechanisms. A positive feedback mechanism is the exact opposite of a negative feedback mechanism. With negative feedback, the output reduces the original effect of the stimulus. In a positive feedback system, the output enhances the original stimulus.
1 Homeostasis is an organismâs ability to maintain a stable internal environment. 2  Homeostasis is an important characteristic of living things. 3  Keeping a stable internal environment requires constant adjustments as conditions change inside and outside the cell.4  Feedback regulation mechanisms are important to homeostasis.he endocrine system plays an important role in homeostasis because hormones regulate the activity of body cells. The release of hormones into the blood is controlled by a stimulus. For example, the stimulus either causes an increase or a decrease in the amount of hormone secreted.