1. Discuss the difference between negative and positive feedback as it relates to homeostasis? Give an example of positive or negative feedback in the body. 2. Briefly describe the communicable disease known as the West Nile Virus and discuss how it may be prevented? Purchase the answer to view it
Negative and positive feedback are two mechanisms by which the body maintains homeostasis, the stable internal environment necessary for proper body functioning. While both types of feedback play important roles in regulating physiological processes, they differ in their effects on the body and the mechanisms they employ.
Negative feedback is a regulatory mechanism that maintains the body’s internal environment within narrow limits. It works to counteract any changes or deviations from the set point in order to restore balance. When a change is detected, negative feedback initiates responses that act in opposition to the change, effectively bringing the system back to its original equilibrium. This type of feedback is characterized by a “stop signal” once the desired condition is restored.
For example, consider the regulation of body temperature: when body temperature rises above the set point, negative feedback mechanisms are activated to bring it back to normal. The hypothalamus, a region in the brain, detects the rise in temperature and triggers responses to cool the body down. These responses include dilation of blood vessels in the skin to promote heat loss and the activation of sweat glands to produce sweat, which cools the body as it evaporates. Once the body temperature returns to the set point, the negative feedback loop is turned off.
On the other hand, positive feedback is a mechanism that amplifies or reinforces a change or deviation from the set point. Unlike negative feedback, it does not work to restore balance, but instead promotes further deviation from the normal state. Positive feedback loops involve a self-perpetuating cycle that keeps reinforcing the initial change until an external interruption occurs.
A classic example of positive feedback in the body is the process of childbirth. When labor begins, uterine contractions increase in intensity and frequency. As the baby’s head pushes against the cervix, the stretching of the cervix stimulates nerve signals to the brain, which in turn releases oxytocin, a hormone that stimulates more contractions. This positive feedback loop continues until the baby is born and the cycle is interrupted.
While negative feedback is the primary mechanism for maintaining homeostasis, positive feedback plays a role in certain physiological processes. Typically, positive feedback loops contribute to processes that need to be quickly completed and do not require long-term maintenance of homeostasis. Examples include blood clotting, where a cascade of reactions amplifies the formation of a clot until it is large enough to stop bleeding, and the release of hormones during ovulation.
In terms of the West Nile Virus, it is a communicable disease caused by the West Nile Virus (WNV), which is primarily transmitted to humans through the bite of infected mosquitoes. The virus is primarily found in birds but can be transmitted to humans and other mammals through mosquito vectors.
Preventing the spread of the West Nile Virus involves various strategies aimed at reducing mosquito populations and avoiding mosquito bites. Mosquito control measures include eliminating standing water sources where mosquitoes breed, such as stagnant ponds or pools of water, and applying insecticides to kill mosquito larvae. Additionally, individuals can protect themselves from mosquito bites by wearing long sleeves and pants, using mosquito repellents, and staying indoors during peak mosquito activity times.
In conclusion, negative and positive feedback are two mechanisms by which the body regulates homeostasis. While negative feedback works to maintain equilibrium and restore balance, positive feedback amplifies deviations from the set point. The West Nile Virus is a communicable disease transmitted by mosquitoes, and its prevention involves reducing mosquito populations and avoiding mosquito bites.