Here are a few immune responses:
– Allergies. Hypersensitivity to a substance that, if inhaled, ingested or touched, can cause some kind of symptom, like sneezing, rashes and itchiness, among other things. These things happen because the immune system has an exaggerated reaction to foreign agents that are hardly ever harmful. These substances are known as allergens and the symptoms are known as allergic reactions.
An allergic reaction has four components: allergens (the substance that causes the allergy), immunoglobulin E (an antibody that produces immediate allergic reactions), histamine (a substance that is released during an allergic reaction; it is responsible for causing the symptoms) and mastocytes (cells charged with histamine granules; they are found on the skin, nose, eyes and mouth).
– Inflammation. It is a reaction that takes place when an external agent shows up, such as bacteria, radiation, trauma and toxins, among others. This response begins with vasodilation (a broadening of the blood vessels found at the affected area), the objective of which is to allow more blood to reach the region in question. After this, comes reddening, pain and an increase in temperature of the damaged area.
In addition, vasodilation facilitates the arrival of large amounts of defensive elements, such as proteins. This enables the formation of a clot. Inflammatory responses can be acute or chronic. The first one takes place suddenly and the swelling period is short. The second one is slower and can last months or even years. This may happen due to complications or recurring episodes of acute inflammation; or because of an infection.
