How do medicine / drugs get delivered to the place where they're needed? Or do they just get dispersed throughout the body?
Medicines or drugs can be delivered to the specific site in the body where they are needed through a variety of methods. The method of delivery depends on the type of drug, the condition being treated, and the desired effect. Here are some common methods of drug delivery:

1. Oral: The most common method of drug delivery is oral, where the drug is taken by mouth in the form of a pill, capsule, or liquid. The drug is then absorbed into the bloodstream through the digestive system and carried to the site where it is needed.
2. Intravenous (IV): Drugs can also be delivered directly into the bloodstream through an IV, where they can quickly reach the site of action. This method is often used in emergency situations or when a rapid effect is needed.
3. Injection: Drugs can be delivered into the muscle, under the skin, or directly into a specific body part or tissue through injection. This method allows the drug to bypass the digestive system and be delivered directly to the site where it is needed.
4. Topical: Some drugs can be applied directly to the skin, eyes, ears, or nose in the form of a cream, ointment, or drops. This method is often used for local conditions, such as skin infections or eye infections.
5. Inhalation: Drugs can be delivered to the lungs through inhalation, either through a nebulizer or an inhaler. This method is often used for respiratory conditions, such as asthma or chronic obstructive pulmonary disease (COPD).

Once a drug is delivered to the body, it can either be dispersed throughout the body or targeted to a specific site. The degree of dispersion depends on the drug's properties and how it is delivered. Some drugs are designed to target specific cells or tissues, while others are designed to be more general in their action. Ultimately, the goal is to deliver the drug to the site where it is needed in a way that maximizes its effectiveness and minimizes side effects.