Types of Diseases

Disease Does not allow the body to function normally Can affect individual organs or an entire body system Divided into two groups – Infectious and Non-infectious

Infectious Disease An infectious disease is a disease that is caused by the presence of a living thing within the body. When you have an infectious disease, pathogens have gotten inside your body & caused harm.

4 KINDS OF PATHOGENS Bacteria Viruses Fungi Protist

Pathogens Pathogens need food & a place to live & reproduce. Sometimes a human body is a suitable place for a pathogen to meet its needs. Pathogens can spread through contact with………

Another person

Contaminated objects

Animal bite

Environment

When a pathogen enters the body: It works by damaging individual cells within the organs In some cases it attacks an entire body system

Immune System The Body's Defense distinguishing (telling the difference) between the different kinds of pathogens Reacting to each kind according to its type The body has 3 lines of defense

F1rst Line of Defense Against Pathogens Skin-Physical & chemical barrier Mucous & Cilia-trap & remove most pathogens Sneezing & Coughing Chemicals in saliva & stomach acid kill pathogens

Second Line of Defense Triggers inflammatory response. Fluid & white blood cells leak from blood vessels into nearby tissues. White blood cells then fight the pathogens. These wbc’s are called phagocytes. Phagocytes engulf & destroy pathogens. During the inflammatory process, the affected area becomes red, swollen, & warm. Fever may also occur

Immune Response, 3rd Line of Defense The cells of the immune system can distinguish between different kinds of pathogens. The immune system cells react to each kind of pathogen with a defense targeted specifically at the pathogen. White blood cells that target specific pathogens are called lymphocytes.

Noninfectious Diseases Are diseases that are not caused by pathogens in the body. Cardiovascular disease, diabetes, & cancer are examples of noninfectious diseases.

Allergy Is a disorder in which the immune system is overly sensitive to a foreign substance- something not normally found in the body. An allergy develops in response to various foreign substances that set off a series of reactions in the body. An allergen is any substance that causes an allergy. People may be allergic to pollen, dust, molds, some foods, or even some medicines.

Diabetes Your pancreas produces insulin, a chemical that enables body cells to take in glucose from the blood & use it for energy. If you have diabetes, your pancreas fails to produce enough insulin, or the body’s cell fail to properly use insulin. As a result, a person with diabetes has high levels of glucose in the blood and may even excrete glucose in urine. People with diabetes may lose weight, feel weak, & always be hungry.

Cancer Is a disease in which cells multiply uncontrollably, over & over, destroying healthy tissue in the process. As cancerous cells divide over & over, they often form abnormal tissue masses called tumors. A carcinogen is a substance or factor in the environment that can cause cancer.

Care of People with Cancer Surgery, drugs, & radiation are all used to treat cancer. People can reduce their risk of cancer by avoiding carcinogens. They can increase their chance of surviving cancer by having regular medical checkups.

Asthma Affects the lungs and the airways that deliver air to the lungs Causes periodic attacks of wheezing and difficulty breathing

Asthma attacks Occur when the airways become inflamed in response to a stimulus, such as dust, mold, pets, exercise, or cold weather Some attacks start for no apparent reason