The immune system

The function of the immune system

The immune system, which is made up of special cells, proteins, tissues, and organs,defends people against germs and microorganisms every day. But sometimes problems with the immune system can lead to illness and infection.The immune system is the body's defense against infectious organisms and other invaders. Through a series of steps called the immune response, the immune system attacks organisms and substances that invade body systems and cause disease.

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Why are antibiotics only effective on bacteria and not on viruses?

Antibiotics are produced by microorganisms to kill or control the growth of other microorganisms by blocking specific metabolic pathways within the cell. Since bacteria are so different to human cells, antibiotics can be taken by humans to kill bacteria without harming the human cells. Viruses on the other hand are different as they do not carry out many metabolic processes themselves. Instead they rely on a host cell (a human cell) to carry out these processes for them. Therefore viruses cannot be treated with antibiotics as it is impossible to harm the virus without harming the human cells.

Adrenal insufficiency (Addison's disease)

The adrenal gland releases too little of the hormone cortisol and sometimes, aldosterone. Symptoms include fatigue, upset stomach, dehydration, and skin changes. Addison's disease is a type of adrenal insufficiency. Addison's disease is a rare endocrine, or hormonal disorder that affects about 1 in 100,000 people. It occurs in all age groups and afflicts men and women equally. The disease is characterized by weight loss, muscle weakness, fatigue, low blood pressure, and sometimes darkening of the skin in both exposed and non-exposed parts of the body.Treatment of Addison's disease involves replacing, or substituting, the hormones that the adrenal glands are not making. surgery is also available


HIV, which causes AIDS, is an acquired viral infection that destroys important white blood cells and weakens the immune system. People with HIV/AIDS become seriously ill with infections that most people can fight off. These infections are called "opportunistic infections" because they take advantage of weak immune systems. symtoms include

Headache,Diarrhea,Nausea and vomiting,Fatigue,Aching muscles,Sore throat,Red rash that doesn't itch, usually on the torso and Fever. there is currently no cure for HIV

pathogens, active immunity, passive immunity, antigen, and antibodys.

Pathogen-an infectious agent such as a virus, bacterium, prion, fungus, or parasite that causes disease in its host

Active immunity- occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response.

Passive immunity- is the transfer of active humoral immunity in the form of ready-made antibodies, from one individual to another.

Antigen- is any structural substance which serves as a target for the receptors of an adaptive immune response

Antibody- also known as an immunoglobulin (Ig), is a large Y-shape protein produced by plasma cells that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses.