Diseases of the Immune System and Hemostasis Overview

These flashcards cover various aspects of the immune system diseases, hypersensitivity reactions, hemostasis, and disorders related to blood coagulation.

What is the primary function of the immune system?

Protection from infections and development of cancer.

What are the two defense systems of the immune system?

Innate immunity and adaptive immunity.

How quickly does the innate immune system respond to antigens?

Immediately or within minutes to hours.

What are the barriers involved in innate immunity?

Skin, mucosal epithelia, and cilia.

What is the complement system?

A complex cascade of proteins that forms a membrane attack complex to lyse plasma membranes.

What defines adaptive immunity?

It is specific and has memory.

Name the two branches of the adaptive immune system.

Cell-mediated immunity and humoral immunity.

What are the players of innate immunity?

Anatomic barriers, physiologic factors, inflammatory response, and plasma proteins.

What role do natural killer (NK) cells play in the immune system?

They are nonspecific cytotoxic cells important in early responses to tumor cells and viral infections.

What are pathogen-associated molecular patterns (PAMPs)?

Molecules associated with groups of pathogens that are recognized by the immune system.

What are Toll-like receptors (TLRs)?

Pattern recognition receptors located on plasma and endosomal membranes that recognize microbial molecules.

What is Type I hypersensitivity?

Immediate hypersensitivity mediated by IgE in response to allergens.

What is the significance of MHC molecules?

They play a key role in self-tolerance and immune recognition.

Differentiate between CD4+ and CD8+ T lymphocytes.

CD4+ T cells are helper T cells and CD8+ T cells are cytotoxic T cells.

What is the role of B lymphocytes in the immune response?

They produce antibodies that protect against extracellular pathogens.

Name a disorder associated with Type II hypersensitivity.

Autoimmune hemolytic anemia.

What triggers Type III hypersensitivity reactions?

The formation of antigen-antibody complexes that activate complement.

What is disseminated intravascular coagulation (DIC)?

A severe dyshomeostasis causing widespread microthrombosis and consumption of coagulation factors.

What is the cause of thrombosis?

Disruption of hemostasis leading to abnormal coagulation in the absence of bleeding.

List the three main causes of thrombosis according to Virchow's triad.

Endothelial injury, alterations in blood flow, and hypercoagulability.

What are the clinical signs of shock?

Weakness, tachypnea, tachycardia, hypotension, decreased urine production, and pale/cool skin.

Describe the significance of arterial thrombi.

They typically have a firm vascular attachment and appear dull and pale due to rapid blood flow.

What is systemic lupus erythematosus (SLE)?

An example of a disease caused by Type III hypersensitivity.

What effect do antihistamines have on allergic reactions?

They block the effects of histamine to reduce symptoms of allergic reactions.

How does the immune system distinguish self from non-self?

Through the recognition of self-antigens by immune cells.

What is the importance of opsonization in the immune response?

It enhances phagocytosis by marking pathogens for destruction.

What does the term 'thrombocytopenia' signify?

A decrease in platelet count.

What are the effects of thromboxane A2 (TXA2)?

Induces vasoconstriction and enhances platelet aggregation.

Identify a significant characteristic of venous thrombi.

They generally occur in areas of blood stasis and are often soft and dark red.

What happens during the sensitization phase of Type I hypersensitivity?

Initial exposure leads to activation of TH2 cells and IgE production by B lymphocytes.

What determines the clinical signs of Type I hypersensitivity?

The target organs and the overall distribution of mast cells.

How is hypovolemic shock characterized?

By decreased blood volume, often due to hemorrhage or severe dehydration.

What is the relationship between cytokines and the immune response?

Cytokines are signaling molecules that regulate immunologic responses.

What type of immunity is based on the ability to recognize specific antigens?

Adaptive immunity.

What does a 'thrombus' refer to in a clinical context?

An aggregate of coagulated blood containing platelets, fibrin, and often entrapped cells.

Describe how endothelial injury contributes to thrombosis.

It exposes collagen and tissue factor, promoting platelet aggregation and fibrin formation.

What constitutes the innate immune system's response to viral infections?

Natural killer (NK) cells and the release of interferons.

What is the main mediator in Type II hypersensitivity reactions?

IgG and IgM antibodies targeting cell-associated antigens.

What outcomes result from the binding of PAMPs to Pattern Recognition Receptors (PRRs)?

Activation of the immune response, leading to inflammation.

What is the role of dendritic cells in adaptive immunity?

They act as antigen-presenting cells for T lymphocytes.

How do immunodeficiencies affect the immune response?

They reduce the body's ability to mount defenses against infections.

List the types of hypersensitivity reactions.

Type I (Immediate), Type II (Cytotoxic), Type III (Immune Complex), and Type IV (Cell-mediated).

What is the first step in hemostasis?

Vasoconstriction at the site of vascular injury.

Explain the term 'hemorrhage'.

Loss of blood due to the rupture or leakage from blood vessels.

What characterizes anaphylactic shock?

Severe systemic allergic reaction causing vasodilation and increased vascular permeability.

What are the potential consequences of thrombocytopathia?

Abnormal platelet function leading to inadequate hemostasis.

How does the body regulate hemostasis?

Through the balance of activation of coagulation factors and the presence of inhibitors.

What is the clinical significance of thrombosis formations?

Can cause ischemia and infarction due to blocked blood flow.

Describe the pathophysiology of DIC.

Widespread clotting factors activation leads to consumption and severe bleeding.

Which cells are responsible for the production of antibodies?

B lymphocytes.

How do T cells recognize antigens?

Through T-cell receptors (TCR) that bind to processed antigens presented by MHC molecules.

What is the role of immunoglobulin E (IgE) in allergic reactions?

It binds to allergens and triggers mast cell degranulation.

What causes systemic lupus erythematosus (SLE)?

Formation of antigen-antibody complexes causing systemic inflammation.

Which type of shock is characterized by vasodilation and pooling of blood?

Distributive shock.

What is the purpose of desensitization therapy?

To gradually reduce the allergic response to specific allergens.

What is the primary mediator of Type IV hypersensitivity?

T lymphocytes.

Name one clinical sign of thrombocytopenia.

Petechiae or ecchymosis on mucosal surfaces.

How does the immune system adapt after exposure to an antigen?

Through memory lymphocytes that provide faster responses upon re-exposure.

What role does the complement system play in the immune response?

It enhances the ability to clear pathogens through opsonization and cell lysis.

What is the significance of levels of antibodies relative to antigens in Type III hypersensitivity?

The ratio determines whether the complexes will form and cause tissue damage.

Describe the physiological response during the progressive stage of shock.

Blood pooling and tissue hypoperfusion leading to lactic acidosis.

How is hemophilia inherited?

As a sex-linked recessive trait.

What is a common outcome of systemic inflammatory response syndrome (SIRS)?

Organ dysfunction and potential multi-organ failure.

What types of factors are evaluated in a coagulation profile?

Coagulation factors measured include factors I (fibrinogen) through XIII.

Explain the relationship between vitamin K and coagulation factors.

Vitamin K is necessary for the synthesis of several coagulation factors.

Who are at higher risk for developing von Willebrand's disease?

Certain breeds like Dobermans and Scottish terriers.

What is a key characteristic of a postmortem clot?

Lacks a point of vascular attachment and is often gelatinous.

What are the indicators of abdominal bleeding?

Hemoperitoneum.

How does septic shock differ from other types of shock?

It is caused by infection and results in systemic inflammation and vasodilation.

What is the clinical marker for shock progression?

Tissue hypoperfusion and elevated lactate levels.