A&P 2: The Immune System Lecture Flashcards

Do antibodies kill pathogens?

No. Antibodies specifically bind to antigens, triggering macrophages and complement to eliminate the pathogen.

Why isn’t there a vaccine for the common cold?

Over 250 different viruses cause the common cold.

Why do I need a flu shot every year?

Influenza viruses mutate frequently, and beneficial genetic changes enhance their spread.

What organ transplant is an autograft?

From one body site to another in same person.

What organ transplant is an Isograft?

Between identical twins.

What organ transplant is an allograft?

Between individuals who are not identical twins.

What organ transplant is a xenograft?

From another animal species.

What is the key factor for a successful organ transplant?

Similarity of tissues between donor and recipient.

What are the ideal types of donor tissues for organ transplants?

Autografts (from the same individual) and isografts (from an identical twin).

What conditions increase the success of organ transplants?

A good blood supply and absence of infection.

What is the most common type of organ transplant?

Allograft (a transplant between genetically different individuals of the same species).

What factors must be matched as closely as possible in an allograft?

ABO blood group, other blood antigens, and MHC (major histocompatibility complex) antigens.

What is the main treatment used to prevent organ rejection after surgery?

Immunosuppressive therapy.

What type of drugs are used to suppress inflammation in transplant patients?

Corticosteroid drugs.

What is the purpose of antiproliferative drugs in organ transplants?

Prevent the rapid growth and division of immune cells that could attack the transplanted organ.

Why are immunosuppressant drugs used in transplant patients?

To weaken the immune system and prevent rejection of the transplanted organ.

What is a major drawback of immunosuppressive therapy?

Many of the drugs have severe side effects.

What is a major problem with immunosuppressive therapy?

It suppresses the patient’s immune system, making them vulnerable to infections.

Why are transplant patients at higher risk of bacterial and viral infections?

Their immune system is weakened by immunosuppressive drugs, reducing their ability to fight infections.

How do doctors balance immunosuppressive therapy in transplant patients?

They must ensure graft survival while minimizing drug toxicity.

How are infections controlled in transplant patients undergoing immunosuppressive therapy?

Antibiotics are used to help manage infections.

Under the best circumstances, what is the long-term success rate of organ transplants?

Even under ideal conditions, 50% of patients experience rejection after 10 years.

What is an immunodeficiency?

A congenital/acquired condition that impairs the function or production of immune cells, complement, or antibodies.

What is Severe Combined Immunodeficiency (SCID) Syndrome?

A genetic disorder causing a severe deficiency in both B and T cells, leaving the immune system unable to fight infections.

What enzyme is defective in SCID?

Adenosine deaminase (ADA) enzyme.

How does a defective ADA enzyme affect the immune system?

It causes toxic metabolites to accumulate, which are lethal to T cells.

Why is SCID fatal if untreated?

The body lacks functional B and T cells, making it unable to defend against any infections.

What is the primary treatment for SCID?

Bone marrow transplants, since bone marrow produces B and T cells.

What causes AIDS?

The human immunodeficiency virus (HIV), which is transmitted through body fluids like blood, semen, and vaginal secretions.

How can HIV be transmitted?

Through blood transfusions, blood-contaminated needles, sexual intercourse, oral sex, and from mother to fetus.

What type of immune cells does HIV destroy?

Helper T cells (CD4 cells).

How does HIV affect the immune system?

By destroying helper T cells, HIV weakens both humoral and cell-mediated immunity.

How long can the asymptomatic period of HIV last if untreated?

The asymptomatic period can last about 10 years.

When do symptoms of AIDS appear?

Symptoms appear when the immune system collapses.

What effect does HIV have on the brain?

HIV invades the brain, leading to dementia.

How does HIV enter a host cell?

HIV attaches to the CD4 receptor with its glycoprotein complex, allowing it to enter the cell.

How does HIV reproduce inside a host cell?

Uses reverse transcriptase to convert its viral RNA into DNA, directs the host cell to make viral RNA and proteins, enabling the virus to reproduce.

Increased HIV viral load causes decreased…?

CD4 T-cell count

What happens in autoimmune diseases?

Immune system loses the ability to distinguish self from foreign, leading to the production of autoantibodies and sensitized TC cells that destroy body tissues.

What are autoantibodies?

Antibodies that target the body’s own tissues, leading to autoimmune reactions.

What types of cells are involved in autoimmune diseases?

Autoantibodies and sensitized T cytotoxic (TC) cells.

What are some examples of autoimmune diseases?

Multiple sclerosis, myasthenia gravis, Graves' disease, type 1 diabetes mellitus, systemic lupus erythematosus (SLE), glomerulonephritis, and rheumatoid arthritis.

How are autoimmune diseases typically treated?

By suppressing the entire immune system.

What type of drugs are commonly used to treat autoimmune diseases?

Anti-inflammatory drugs, such as corticosteroids.

How can cytokine action be blocked in autoimmune disease treatment?

By using drugs that block cytokine action.

What are co-stimulatory molecules and how are they involved in autoimmune treatment?

Are involved in immune activation, and blocking them can help reduce autoimmune responses.

What are some areas of research in treating autoimmune diseases?

Activating regulatory T cells, inducing self-tolerance with vaccines, and directing antibodies against self-reactive immune cells.

What causes hypersensitivity reactions?

Immune responses to perceived (otherwise harmless) threats, leading to tissue damage.

How are different types of hypersensitivity distinguished?

By their time course and whether antibodies or T cells are involved.

What type of hypersensitivity is caused by antibodies?

Antibody-mediated hypersensitivity causes immediate and subacute reactions.

What causes delayed hypersensitivity?

Delayed hypersensitivity is caused by T cells.

What are allergic reactions in immediate hypersensitivity?

Allergic reactions can be local or systemic, causing tissue damage and inflammation.

Where do local allergic reactions occur?

Local reactions occur in the mast cells of the skin, respiratory, and gastrointestinal mucosa.

How do histamines affect the body in an allergic reaction?

Histamines cause blood vessels to dilate and become leaky, leading to symptoms like a runny nose, hives, and watery eyes.

What happens when an allergen is inhaled?

It can trigger asthma, causing difficulty in breathing.

How can allergic reactions be controlled?

Antihistamines are used to control allergic reactions.

What is a systemic allergic response called?

Anaphylactic shock is a severe, systemic response to an allergen.

What is anaphylactic shock?

A severe, systemic allergic reaction that occurs when an allergen enters the bloodstream and spreads rapidly.

What immune cells are involved in anaphylactic shock?

Basophils and mast cells are activated throughout the body.

What are the effects of systemic histamine release in anaphylactic shock?

Constriction of bronchioles, swelling of the tongue, massive vasodilation, and fluid loss from the bloodstream.

Why does blood pressure drop in anaphylactic shock?

Sudden massive vasodilation causes blood pressure to drop, leading to circulatory collapse.

What is the most severe consequence of anaphylactic shock?

Circulatory collapse (hypotensive shock), which can lead to death if untreated.

What causes subacute hypersensitivities?

They are caused by IgM and IgG antibodies transferred via blood plasma or serum.

How quickly do subacute hypersensitivity reactions occur and how long do they last?

They have a slow onset (1–3 hours) and a long duration (10–15 hours).

What is another name for cytotoxic hypersensitivity?

Type II hypersensitivity reaction.

How do antibodies contribute to cytotoxic (type II) reactions?

Antibodies bind to antigens on specific body cells, leading to phagocytosis and complement-mediated lysis of the targeted cells.

What is an example of a cytotoxic (type II) hypersensitivity reaction?

A mismatched blood transfusion reaction.