Question

feedback mechanisms
directions: read the passage below. then answer the questions that follow.
the word homeostasis is derived from greek words that mean “to stay the same,” but this definition can be misleading. a body’s internal state does not stay exactly the same. instead, as figure 14 shows, it varies around a certain average value. homeostasis maintains a dynamic equilibrium. to maintain homeostasis, your body has a diversity of feedback mechanisms that detect deviations in the body’s internal environment and make corrective actions. a feedback mechanism is a mechanism in which the last step in a series of events controls actions. a feedback mechanism has three parts. first, a receptor, such as a nerve, detects change in the internal or external environment. second, a control center, such as the brain, selects a response to the information from the receptor. third, an effector, such as a muscle or gland, carries out the response, and this effect is detected by the receptor, which starts the process again.
directions: read each question, and write your answer in the space provided.

1. using context clues in the passage, explain the meaning of the term dynamic equilibrium.
2. what is a feedback mechanism?
3. what is the relationship between feedback mechanisms and dynamic equilibrium in the human body?
4. list and describe the three parts of a feedback mechanism.
5. for a feedback mechanism to work, a(n) ____ must first detect a change in the body’s internal or external environment.

a. gland
b. effector
c. receptor
d. control center

Explanation:

1. The passage indicates that a body's internal state varies around a certain average value and homeostasis maintains this. So, dynamic equilibrium is a state where the body's internal state fluctuates around an average value while still being relatively stable.
2. The passage defines a feedback mechanism as a mechanism in which the last step in a series of events controls actions. It has three parts: a receptor to detect change, a control - center to select a response, and an effector to carry out the response.
3. Feedback mechanisms are what the body uses to maintain dynamic equilibrium. They detect deviations in the body's internal or external environment and make corrective actions to keep the body in a state of dynamic equilibrium.
4. The three parts are: Receptor (e.g., a nerve) which detects change in the internal or external environment; Control center (e.g., the brain) which selects a response to the information from the receptor; Effector (e.g., a muscle or gland) which carries out the response and whose effect is detected by the receptor.
5. According to the passage, for a feedback mechanism to work, a receptor must first detect a change in the body's internal or external environment.

Answer:

1. A state where the body's internal state fluctuates around an average value while remaining relatively stable.
2. A mechanism in which the last step in a series of events controls actions, having a receptor, a control - center, and an effector.
3. Feedback mechanisms are used by the body to maintain dynamic equilibrium by detecting and correcting deviations.
4. Receptor: Detects environmental change; Control center: Selects a response; Effector: Carries out the response.
5. C. receptor