malfunctions of the immune system

Question 1

what are the 3 types of malfunctions of immunity system?

Answer 1

1. hypersensitivity
2. immunodeficiency disorders
3. autoimmune diseases

Question 2

what is hypersensitivity?

Answer 2

1. occurs when the immune system responds to antigens that are not harmful to the body. the response, rather than the antigen, can cause disease
2. Type I hypersensitivity (allergy): response to harmless antigens. e.g, allergens include pollen, animal fur, dust, insect bites or stings and foods such as peanuts.
3. an allergic reaction occurs when plasma cells produce antibodies called immunoglobulin E in response to an allergen. the constant region of some IgE bind to mast cells
4. the mast cell releases histamine and other substances. histamine triggers the inflammatory response and other allergic reactions such as itchiness, runny nose and watery eyes.
5. the strength of the allergic reaction varies between people. mild reactions include hay fever. anaphylaxis is an extreme, life-threatening reaction. if untreated, this can cause fatal swelling of the throat and respiratory passages.
6. antihistamines are medications that reduce mild allergic reactions by blocking histamine receptors on body cells.

Question 3

what is immunodeficiency?

Answer 3

1.opposite of hypersensitivity. occurs when the immune system does not respond properly or at all to pathogens
2. people with primary immunodeficiency disorders are born with them. genetic factors usually cause primary immunodeficiency. e.g, severe combined immunodeficiency disease (SCID). people with SCID cannot produce functioning B and T cells and are highly susceptible to all pathogens
3. secondary immunodeficiency disorders are acquired, or develop during the lifetime of the person. environmental factors such as extreme stress, malnutrition or exposure to a pathogen cause secondary immunodeficiency disorders.
4. HIV/AIDS

Question 4

what is HIV/AIDS?

Answer 4

• HIV causes AIDS
• HIV is a retrovirus, they contain RNA, but are able to force the host cell to convert the RNA into DNA. the viral DNA is then hidden in the host cell’s DNA. some viruses will survive by hiding in host cells while the immune system will fight the initial infection of HIV
• HIV tends to target helper T cells. the destruction of these cells results in a reduced functioning of both B and T cells. this impairs the adaptive immunity
• people with AIDS are more susceptible to other pathogens. these additional infections are the usual cause of death in AIDS patients
• no cure, only antiretroviral medications can slow or prevent the virus from replicating and prevent AIDS from developing,

Question 5

what is an autoimmune disease?

Answer 5

• B and T cells attack and destroy self-cells like how they would do to pathogens
• affects the whole body , or attacks a specific body system or organ
• multiple sclerosis- an autoimmune disease that affects Schwann cells and myelin
• plasma cells produce antibodies and bind to proteins and lipids that make up the myelin sheath
• B and T cells also attack the Schwann cells. Eventually the exposed axons become damaged. Demyelinated 2axons cannot pass the nerve impulse as quickly as insulated axons and the signals can get mixed up between different neurons.
• immunosuppressants to reduce the response of the immune system: delays progression