1. Define the term "homeostasis".
Answer
Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.
2. Which condition is not controlled by homeostasis in the human body ?
a) blood glucose concentration b) body temperature c) oxygen concentration in the blood d) water levels
Answer
c) oxygen concentration in the blood
3. What are the two main types of responses of the automatic control systems in the body ?
a) muscular and skeletal b) circulatory and respiratory c) hormonal and digestive d) nervous and chemical
Answer
d) nervous and chemical
4. Which type of cell detects stimuli in the human body ?
a) receptor cells b) red blood cells c) muscle cells d) gland cells
Answer
a) receptor cells
5. The control systems of the body can involve nervous or chemical responses. Describe the main features that are found in all control systems.
Answer
All control systems have cells called receptors which detect stimuli or changes in the environment. Coordination centres, for example the brain, receive and process information from receptors. Effectors, muscles or glands, then bring about responses which restore optimum levels.
6. One of the conditions controlled in the human body is temperature. Explain why it is important to control body temperature.
a) to keep blood pressure constant
b) to maintain the optimum temperature for enzyme action
c) to ensure continuous oxygen supply
d) to prevent water loss through sweating
Answer
b) to maintain the optimum temperature for enzyme action
7. Why is it important to control blood glucose concentration in the human body ?
a) to maintain constant blood pressure
b) to prevent excess water loss
c) because glucose is required for respiration to release energy for the body
d) to regulate the rate of protein synthesis
Answer
c) because glucose is required for respiration to release energy for the body
8. The figure below shows some organs of the human body. Name the organ that produces urea, produces urine and controls body temperature.
Answer
The liver produces urea, the kidneys produce urine, and the skin controls body temperature.