Health, disease and the development of medicines Study Guide

The presence of one disease can weaken the body's natural defences, making an individual more vulnerable to acquiring other diseases. This increased susceptibility often stems from the specific ways diseases affect the immune system or compromise other crucial bodily functions. For example, certain conditions directly suppress immune cell activity, like HIV/AIDS which targets T-helper cells, severely hindering the body's ability to fight off opportunistic infections. Other diseases might damage physical barriers, such as the skin or mucous membranes, which form the first line of defence against pathogens. Chronic illnesses can also divert the body's resources towards managing the existing condition, leaving fewer resources available to mount an effective immune response against new threats. The combined stress on the body from one illness can lead to a general state of reduced health, making it harder to recover from subsequent infections. This interconnectedness highlights the complex nature of human health and disease.

Antibiotics are a class of antimicrobial drugs specifically designed to combat bacterial infections. Their effectiveness stems from their ability to target and interfere with biological processes vital to bacteria, but which are either absent or sufficiently different in human cells. For instance, many antibiotics inhibit bacterial cell wall synthesis. Bacterial cells possess a rigid cell wall, which human cells lack. By preventing its formation or damaging its structure, the antibiotic weakens the bacterium, leading to its death. Other antibiotics might target bacterial protein synthesis by binding to bacterial ribosomes, which differ structurally from human ribosomes. This specificity is crucial; it allows antibiotics to eliminate the invading bacteria without causing significant harm to the host’s cells. This fundamental difference means antibiotics are ineffective against viral infections or other types of pathogens, as these organisms do not share the targeted bacterial processes.