1. List the four biological levels of organization in a human in order from most simple to most complex.
Cells, tissues, organs, organ systems
2. Define the term “homeostasis”.
The tendency of the body to maintain a relatively constant internal environment.
3. What does the term “feedback system” refer to with respect to homeostasis?
A cycle of events in which a variable, such as body temperature, is continually monitored, assessed, and adjusted.
4. List the three components of a feedback system and describe each briefly.
A sensor that detects a change in the internal environment and sends a signal to a control centre
A control centre that sets the range of values with which a variable should be maintained, receives information from a sensor, and sends signals to an effector
An effector that receives signals from the control centre and responds, resulting in a change to an internal variable
5. Summarize the connection between the integumentary system and the nervous system.
The sensory receptors in the integumentary system communicate with the brain and spinal cord via the nerves (the three parts of the nervous system).
6. Using the stomach as an example, illustrate the four biological levels of organization as a human.
The stomach is composed of individual cells. Cells of the same type that perform a common function make up tissues, such as those that line the stomach. One or more tissues interact to form more complex structures known as organs, such as the stomach. Several organs, such as the stomach and small intestine, are organized structurally and functionally to form an organ system, such as the digestive system.
7. Explain why the nervous system is critical for maintaining homeostasis.
The human nervous system can regulate tens of thousands of activities simultaneously. Its overall function is to collect information about the external conditions in relation to the body’s internal state, analyze it,