SCIENCE 10 Q3 FEEDBACK MECHANISM

• Most body systems maintain homeostasis (internal balance/equilibrium) by using feedback mechanism. A feedback mechanism is the process through which the level of one substance influences the level of another substance. Feedback mechanism can be positive or negative feedback. 
• The key difference between positive and negative feedback is their response to change. Positive feedback increases change while negative feedback reduces change. Negative feedback will result in less of a product: less heat, less pressure, or less salt. In positive feedback, the input and output signals are of similar phase and so the two signals get added. While in negative feedback, the input and output signals are of different phases thus the two are subtracted.
• When the brain receives messages from the body about an internal change in one of its systems, it works to restore the system in its normal state. The levels of hormones in the body are controlled by the feedback. It is important that the number of hormones in the body are kept at the right level.
• The endocrine system plays an important role in homeostasis such as thermoregulation (if body temperature changes, mechanisms are induced to restore normal levels) and blood sugar regulation (insulin lowers blood glucose when levels are high; glucagon raises blood glucose when levels are low)
• To achieve homeostasis, the nervous system and endocrine systems maintain a normal range of the following: body temperature, amount of water in the body, amount of metabolic waste in the cell, blood calcium level and hormones in the blood.
• Negative feedback affects the production of hormones such as in menstrual cycle. That is, high levels of one hormone may inhibit or stop the production of another hormone.

  
• The human chorionic gonadotropin (hCG) hormone produced by the developing placenta (inulnan in bicol), plays a crucial role in maintaining the corpus luteum and preventing a decline in progesterone levels, thereby supporting pregnancy. Later, around the 10th week pregnancy, the placenta takes over progesterone production, ensuring a sustained level throughout the gestation period (time it takes for a fetus to develop and grow inside the womb).
• fill in the missing terms

  A) cervix

  B) oxytocin

  C) contract