Micro Chapter 17

First Line of Defense

Surface protection by anatomical and physiological barriers to prevent microbial penetration.

Skin

Acts as a primary barrier against pathogen entry.

Mucous Membranes

Trap pathogens and particles to prevent infection.

Second Line of Defense

Cellular and chemical responses that activate upon pathogen breach.

Inflammation

Localized response to tissue injury characterized by redness, warmth, swelling, pain, and loss of function.

Phagocytosis

Process by which cells engulf and destroy pathogens.

Third Line of Defense

Acquired specific immunity developed uniquely for each pathogen via specialized white blood cells.

B Lymphocytes

White blood cells that produce antibodies.

T Lymphocytes

White blood cells that destroy infected cells and coordinate the immune response.

Physical Defenses

Mechanical barriers and other strategies to block pathogens.

Shedding of Skin

Removes pathogens through natural exfoliation.

Mucociliary Sweeping

Mechanism that clears pathogens from respiratory passages.

Flushing Actions

Processes such as urination and tearing that help expel pathogens.

Microbiome Role

Normal resident bacteria compete with pathogenic microorganisms for binding sites and nutrients.

Chemical Defenses

Biochemical barriers that impede pathogen functionality.

Sebum

Oily substance that protects skin and provides nutrients for microbiome.

Lysozyme

Enzyme that breaks down bacterial cell walls, found in saliva, tears, and sweat.

Acidic pH

Inhibits pathogen growth on the skin surface.

Gastric Juice

Contains digestive enzymes that destroy pathogens ingested with food.

Antimicrobial Peptides (AMPs)

Small proteins that disrupt microbial membranes.

Plasma Protein Mediators

Involved in signaling immune responses to increase defense mechanisms.

Granulocytes

Type of white blood cells that include neutrophils, eosinophils, and basophils.

Eosinophils

Target larger parasites and phagocytose antigen-antibody complexes.

Basophils

White blood cells involved in inflammatory responses by releasing histamine.

Agranulocytes

Includes lymphocytes and monocytes, which have specific immune functions.

Lymphocytes

Include B cells and T cells involved in adaptive immunity.

Macrophages

Chief phagocytic cells that engulf pathogens and tissue debris.

Pathogen-Associated Molecular Patterns (PAMPs)

Unique molecules expressed by pathogens recognized by PRRs.

Pattern Recognition Receptors (PRRs)

Receptors on phagocytic cells that detect foreign molecules.

Histamine Release

Increases blood flow, allowing immune cells to reach the injury site more effectively.

Fever

Systemic response to infection characterized by an increase in body temperature.

Exogenous Pyrogens

Fever-inducing substances derived from outside the body, such as bacterial toxins.

Endogenous Pyrogens

Produced by leukocytes, such as Interleukin-1 and TNF, to induce fever.

Complement System

A series of blood proteins activated in response to pathogens.

Classical Pathway

Triggered by antibody-pathogen complexes to activate the complement system.

Lectin Pathway

Activated by host serum proteins binding to pathogens.

Alternative Pathway

Initiated by complement proteins binding directly to microbes.

C3 Complement Protein

Central to the activation of the complement system, leading to cell lysis.

Cell Lysis

The destruction of a cell through disruption of its membrane.

Pathogen Recognition

The ability of immune cells to identify foreign pathogens.

Inflammatory Response

The body's immediate reaction to injury or infection.

Tissue Injury

Damage to tissue that triggers immune responses.

Antibody

A protein produced by B cells that specifically binds to antigens.

White Blood Cells

Cells of the immune system involved in protecting the body from infectious disease.

Immune Response

The body's defense mechanism against foreign invaders.

Phagocytic Cells

Cells that can engulf and absorb bacteria and other small cells.

Metabolic Activity

The sum of all biochemical processes occurring in an organism.

Normal Flora

Bacteria that reside in the body normally and can prevent infections.

Natural Barriers

First line of defense against pathogens, including skin and mucous membranes.

Cytokines

Proteins that mediate and regulate immunity and inflammation.

Infection

The invasion of the body by pathogenic microorganisms.

Mechanisms of Defense

Various strategies employed by the immune system to protect the body.

Pathogen Breach

Breakthrough of a pathogen through the body's defenses.

Antigen-Antibody Complex

A complex formed when an antibody binds to an antigen.

Tissue Debris

Dead cells and molecules present at an injury site.

Swelling

Increase in volume due to fluid accumulation in tissues.

Redness

Increased blood flow to an affected area, a sign of inflammation.

Increased Blood Flow

More blood flowing to an area, often resulting in redness and warmth.

Pain Reaction

Nerve response to injury or inflammation.

Cell Types

Different kinds of cells with specific roles in the immune system.

Lymphatic System

Part of the immune system involved in the production and transport of lymph.

Immune Coordination

Coordination between various immune cells to mount an effective response.

Histamine

A chemical released during inflammatory responses that increases blood vessel permeability.

Local Response

A reaction confined to a specific area of the body.

Serum Proteins

Proteins found in blood serum that have various functions including immunity.

Microbial Membranes

Outer layers of microbial cells that can be disrupted by AMPs.

Adaptive Immunity

The immune response that tailors itself to specific pathogens.

Antibody Specificity

The ability of an antibody to bind to a specific antigen.

Inflammatory Mediators

Substances released by cells that affect other cells in the inflammatory process.

Immune Signaling

Communications between immune cells to orchestrate responses.

Infected Cells

Cells that have been compromised by pathogens and need to be destroyed.

Leukocytes

Another term for white blood cells.

Inflammatory Cells

Cells involved in the inflammation process, including neutrophils and macrophages.

Microbial Infection

The invasion of body tissues by harmful microorganisms.

Antigen Recognition

The process by which immune cells identify and bind to antigens.

Pathogen Elimination

The process through which the immune system removes pathogens from the body.