Med Term Immune and Lymphatic System

What is the lymphatic system?

A network of vessels, organs, and tissues that plays a vital role in immunity and fluid balance

What are the two major functions of the lymphatic system?

Eliminate excess fluid and defend against pathogens

What are T lymphocytes (T cells)?

Immune cells that mature in the thymus

What are B lymphocytes (B cells)?

Immune cells that mature in bone marrow and produce antibodies

What are macrophages?

Phagocytic cells derived from monocytes that destroy foreign invaders

What is a macrophage?

A monocyte-derived white blood cell that engulfs pathogens, debris, and foreign material

What are lymph capillaries?

Small lymphatic vessels that collect interstitial fluid

What is interstitial fluid?

Fluid surrounding body cells

What is a pathogen?

A microorganism that causes disease

What is specificity?

The immune system's ability to target specific pathogens

What is immunological memory?

The ability to remember previous pathogen encounters and respond faster

What is self-recognition?

The ability to distinguish self cells from foreign cells

What is lymph?

Watery fluid transported through lymphatic vessels

How is lymph formed?

Interstitial fluid enters lymphatic capillaries and becomes lymph

What can enter lymphatic capillaries?

Bacteria, viruses, cancer cells, and debris

What do lymphatic vessels eventually drain into?

Subclavian veins

How does lymph enter the bloodstream?

Through the subclavian veins

What are lymph nodes?

Structures that filter lymph and contain immune cells

How many lymph nodes do humans have?

Approximately 500–600

Where are lymph nodes concentrated?

Neck, armpits, chest, abdomen, and groin

What happens to pathogens in lymph nodes?

Macrophages ingest and destroy them

Why are pathogen fragments saved by immune cells?

To help the immune system remember future infections

What is lymphatic tissue?

Tissue containing white blood cells and macrophages

What is the primary function of lymph nodes?

Filter lymph and remove pathogens

What is the function of tonsils and adenoids?

Trap pathogens entering through the throat

Where is the thymus located?

Between the sternum and aorta

What is the function of the thymus?

Maturation of T cells

What happens to the thymus in adulthood?

It is largely replaced by fat

What is the spleen?

A fragile vascular organ that filters blood

What are the functions of the spleen?

Filters blood and acts as a blood reservoir

What is the function of bone marrow?

Produces blood cells and matures B cells

What are the three levels of immune defense?

Barrier defenses, innate immune response, and adaptive immune response

What is a barrier defense?

The body's first line of defense against pathogens

What is the purpose of barrier defenses?

Prevent pathogen entry and remove pathogens before infection develops

How does skin act as a barrier defense?

Sheds cells that carry pathogens away

How do sweat and sebaceous glands help immunity?

Produce substances and pH conditions unfavorable to pathogens

What enzyme in saliva destroys bacteria?

Lysozyme

What is lysozyme?

An enzyme that destroys certain bacteria

How does the stomach protect against pathogens?

Its low pH kills many microorganisms

How do mucous membranes protect the body?

Trap microbes and debris

What is normal flora?

Beneficial bacteria that compete with pathogens

What is the innate immune response?

Rapid, nonspecific defense against infection

What is the purpose of the innate immune response?

Slow pathogen growth and activate adaptive immunity

What cells are important in innate immunity?

Phagocytes

What two common innate immune reactions occur during infection?

Inflammation and fever

What is the adaptive immune response?

A highly specific immune response involving B and T cells

What are antigens?

Molecules recognized by receptors on B and T lymphocytes

What is the primary adaptive response?

The first immune response to a pathogen

Why is the primary response slower?

Time is needed to activate adaptive immunity

What is the secondary adaptive response?

Response to a previously encountered pathogen

How does the secondary response compare to the primary response?

Faster and stronger

What is immunity?

Protection resulting from immunological memory

Why is self-recognition important?

Prevents immune attacks against the body's own cells

What happens when self-recognition fails?

Autoimmune disease develops

What is an immunodeficiency?

A condition involving reduced immune function

What is SCID?

Severe Combined Immunodeficiency Disease

What causes SCID?

Genetic defects affecting B and T cells

How is SCID often treated?

Bone marrow transplantation

What is HIV?

A virus that attacks and weakens the immune system

How is HIV transmitted?

Blood, semen, vaginal fluids, and shared needles

What is AIDS?

Advanced immune deficiency caused by HIV infection

How do HIV medications work?

Target viral proteins needed for replication

What is hypersensitivity?

An exaggerated immune response

What is a Type I hypersensitivity?

Immediate allergic reaction

What are examples of Type I hypersensitivity?

Allergies and allergic asthma

What symptoms are common in Type I hypersensitivity?

Runny nose and nasal edema

What is anaphylactic shock?

A severe, potentially fatal allergic reaction

What medication is used to treat anaphylaxis?

Epinephrine

What is a Type II hypersensitivity?

Reaction involving mismatched blood transfusions or blood incompatibility

What is erythroblastosis fetalis?

A Type II hypersensitivity involving maternal-fetal blood incompatibility

What is a Type III hypersensitivity?

Immune complex disease such as lupus

What is a Type IV hypersensitivity?

Delayed hypersensitivity reaction

How long does Type IV hypersensitivity take to develop?

24–72 hours

What occurs during first exposure in Type IV hypersensitivity?

Sensitization

What occurs during second exposure?

Immune response develops

What is an autoimmune disease?

A disease in which the immune system attacks the body's own tissues

How many autoimmune diseases exist?

More than 80

What is the autoantigen in celiac disease?

Tissue transglutaminase

What is a major symptom of celiac disease?

Damage to the small intestine