1. Body Systems Practice Test A & B Sample Solutions

2. 1A. Explain how your skeletal system is related to the muscular system and the digestive system.  The skeletal system is related to the muscular system because bones are connected to muscles with tendons and function together to help the body move.  The skeletal system is related to the digestive system because the digestive system is used to digest and absorb foods with calcium, which is stored in the bones to make them strong.

3. 1B. Defend the claim: “The cardiac muscles are the most important and strongest muscles of the body.”  The cardiac muscles are the most important because they make up the muscles of your heart and allow it to pump blood to the rest of your body. Without the heart, the body would die.  The cardiac muscles are the strongest because they are constantly working and don’t get much opportunity to rest, unlike the smooth or skeletal muscles.

4. 2A. Defend the claim: “The integumentary system supports the homeostasis of the skeletal system.  The skin is the major organ of the integumentary system. When it is exposed to ultraviolet (UV) radiation, it produces vitamin D. Vitamin D allows the body to absorb more calcium which is used to strengthen the bones of the skeletal system.

5. 2B. Explain how the skeletal system is related to the integumentary system and the muscular system.  The skeletal system is related to the integumentary system because the skin produces vitamin D, which allows the body to absorb calcium. The calcium is stored in the bones.  The skeletal system is related to the muscular system because bones are connected to muscles with tendons and function together to help the body move.

6. 3A. Which function of the muscular system is the most important? Justify your answer. Answers will vary. Choose one of the following functions for you answer: movement, protection, stability, or temperature regulation. Example: Movement is the most important function of the muscular system because it allows a person to eat, breathe, and avoid danger (a type of protection). These are all necessary activities for life, and therefore more important than the other three functions.

7. 3B. Melanin, the pigment in your skin, is made in the epidermis. Knowing this, explain why a person’s tan will “fade” after several weeks.  The epidermis is the superficial and temporary layer of your skin. It is constantly shedding and reproducing itself. Since the melanin is found in this layer, it is lost when the epidermis sheds and is replaced.

8. 4A. Describe how a lack of mechanical digestion in the mouth could affect digestion and absorption in other parts of the digestive system.  A lack of mechanical digestion in the mouth would cause food to take longer to chemically digest in the stomach and small intestine. Likewise, if the food is unable to be properly digested, there would be less nutrients absorbed in the small intestine.

9. 4B. Predict and explain 2 likely issues that would arise if the digestive system was composed of skeletal muscle instead of smooth muscle.  Since skeletal muscle is voluntary and needs to be controlled by thinking about it, the 2 likely issues are:  The food could move through the digestive system too slowly since people would become distracted or forgetful.  The food could move through the digestive system too quickly if the person is in a rush and doesn’t have several hours to spend on thinking about digesting their food. They would not absorb enough nutrients this way.

10. 5A. The excretory system involves several other systems. Hypothesize what the results would be if the functions of the integumentary system no longer worked properly. The integumentary system removes extra water and salt through sweating. If a person was not able to sweat, then he/she would overheat during exercise or warm weather because sweat is the main way the human body cools down.

11. 5B. Defend the claim: “Compared to the other three systems of the excretory system, the elimination of wastes by the respiratory system is the most important.”  The respiratory system removes carbon dioxide from the body. This is the most important waste removal because it involves the process of breathing (exhaling) and a person cannot live for more than a few minutes unless they breathe. The other wastes can be removed hours or days later, but breathing is a constant need of our bodies.