immune system

Which cell type rapidly ingests and destroys bacteria?

Neutrophils

What are the key features of neutrophils?

First responders; form pus; short life span

Which cell type performs phagocytosis and activates T cells?

Macrophages

Key features of macrophages?

Long-living; cytokine release; antigen-presenting

Which cells are professional antigen-presenting cells bridging innate & adaptive immunity?

Dendritic Cells

Main function of dendritic cells?

Bridge between innate & adaptive immunity

Which cells kill virus-infected and cancer cells without prior exposure?

Natural Killer (NK) Cells

Key feature of NK cells?

No MHC requirement; innate response

Which cells release histamine in the blood?

Basophils

Key feature of basophils?

Circulate in blood; involved in allergy responses

Which cells release histamine and mediate inflammation in tissues?

Mast Cells

Key feature of mast cells?

Found in tissues; key for anaphylaxis

Which cells attack parasites and play a role in allergies?

Eosinophils

Key feature of eosinophils?

Release enzymes/toxins

Which cells produce antibodies?

B Cells

Key feature of B cells?

Differentiate into plasma & memory B cells

Which T cells coordinate immune responses and activate other immune cells?

Helper T Cells (CD4+)

Key features of Helper T cells?

Activate B cells, T cells, macrophages

Which T cells kill infected or cancerous cells?

Cytotoxic T Cells (CD8+)

Key feature of cytotoxic T cells?

Target intracellular pathogens

Which T cells prevent overactivation of the immune system?

Regulatory T Cells

Key feature of regulatory T cells?

Maintain immune tolerance

Which T cells provide long-term immunity and respond quickly on re-exposure?

Memory T Cells

Key feature of memory T cells?

Quick response upon re-exposure to antigen

What is the main role of IgG?

Most abundant antibody; primary in secondary immune response; neutralizes toxins, viruses, bacteria; crosses placenta

Location of IgG?

Blood, tissues; crosses placenta

Think mnemonic for IgG?

G = Goes everywhere; Gives baby immunity

What is the main role of IgM?

First antibody produced during infection; excellent at agglutination; activates complement strongly

Location of IgM?

Bloodstream

Mnemonic for IgM?

M = Massive & immediate

What is the main role of IgA?

Protects mucosal surfaces; blocks pathogen attachment; provides passive immunity to infants

Location of IgA?

Secretions: saliva, tears, mucus, breast milk, GI tract

Mnemonic for IgA?

A = Areas exposed to Air (mucosa)

What is the main role of IgE?

Triggers histamine release during allergic reactions; defense against parasites; mediates type I hypersensitivity

Location of IgE?

Bound to mast cells and basophils

Mnemonic for IgE?

E = Environment allergies

What is the main role of IgD?

Acts as a B-cell receptor; helps activate B-cells during initial antigen exposure

Location of IgD?

Surface of B-lymphocytes

Mnemonic for IgD?

D = Development of B-cells

Neutrophils

Rapidly ingest and destroy bacteria; first responders; form pus; short life span

Macrophages

Phagocytosis; activate T cells; long-living; cytokine release; antigen-presenting

Dendritic Cells

Professional antigen-presenting cells; bridge between innate & adaptive immunity

Natural Killer (NK) Cells

Kill virus-infected and cancer cells; no prior exposure needed; no MHC requirement

Basophils

Release histamine; circulate in blood; involved in allergy responses

Mast Cells

Inflammation; histamine release; found in tissues; key for anaphylaxis

Eosinophils

Attack parasites; allergy role; release enzymes/toxins

B Cells

Produce antibodies; differentiate into plasma & memory B cells

Helper T Cells (CD4+)

Coordinate immune responses; activate B cells, T cells, macrophages

Cytotoxic T Cells (CD8+)

Kill infected/cancerous cells; target intracellular pathogens

Regulatory T Cells

Prevent overactivation; maintain immune tolerance

Memory T Cells

Long-term immunity; quick response on re-exposure

IgG

Most abundant antibody (75–80%); primary in secondary immune response; neutralizes toxins, viruses, bacteria; crosses placenta; provides passive immunity to newborns

IgM

First antibody produced during infection; excellent at agglutination; activates complement strongly; indicates recent infection

IgA

Protects mucosal surfaces; blocks pathogen attachment; provides passive immunity to infants; found in secretions like saliva, tears, mucus, breast milk

IgE

Triggers histamine release in allergies; defense against parasites; type I hypersensitivity; bound to mast cells and basophils

IgD

Acts as B-cell receptor; activates B-cells during initial antigen exposure; surface of B-lymphocytes; very low concentration in circulation

What is the focus of Cam Clip 1 for A&P II, Session 6?

The immune system, specifically the relationship between the lymphatic and immune systems and their interaction with other body systems.

How is immunity defined?

Immunity is our resistance to the effects of disease-causing agents.

Why do we all have different immunity?

Because each person makes their own immunity, tailored to who they are.

Why is the immune system essential to life?

It protects us from potentially fatal disease processes, possibly some cancers, and generally keeps us alive by fighting pathogens.

How do we know if our immune system works?

We only know when it doesn’t work; its effectiveness is built-in and specific to defending against diseases.

What is meant by a “silent, portable army” in immunity?

After exposure to a pathogen (e.g., chickenpox), memory cells remain in the body for life, ready to attack the pathogen if it reappears.

What are the necessary components for a healthy immune system?

Lymphatics (filter and clean blood), skin and mucus membranes (mechanical barriers), interferons (proteins that interfere with viruses and tumors), enzymes in body fluids, leukocytes (white blood cells)

What is the first line of defense in the immune system?

Skin and mucus membranes, which act as mechanical barriers to bacteria and pathogens.

What are interferons, and what do they do?

Interferons are proteins that interfere with the proliferation or development of some viruses and tumors.

What is the role of enzymes in immunity?

They protect the body from disease and are present in various body fluids.

How many types of leukocytes are there, and which are phagocytic?

There are five types of leukocytes; neutrophils and monocytes are phagocytic.

What role do neutrophils play?

They act as short-term foot soldiers that increase during acute infections.

What happens to monocytes?

Monocytes mature into macrophages, which live throughout the body.

Where do macrophages reside, and what is their function?

Macrophages reside in lymph nodes, lungs, liver, and other tissues; they are aggressive phagocytes that clean blood and body fluids constantly.

Immunity

The body’s resistance to the effects of disease-causing agents, tailored individually, and essential for survival.

Silent, portable army

Memory cells that remain in the body after infection (e.g., chickenpox) to provide long-term immunity.

Lymphatics

Structures that filter and clean blood; essential for a healthy immune system.

First line of defense

Mechanical barriers like skin and mucus membranes that prevent pathogen entry.

Interferons

Proteins that interfere with the proliferation of some viruses and tumors, working quietly in the background.

Enzymes (immune-related)

Protective proteins in various body fluids that help fight disease.

Leukocytes

White blood cells; five types exist, including phagocytic neutrophils and monocytes.

Neutrophils

Short-term phagocytic leukocytes that increase during acute infection.

Monocytes

Phagocytic leukocytes that mature into macrophages.

Macrophages

Aggressive phagocytes located in lymph nodes, lungs, liver, and other tissues; clean blood and body fluids continuously.

Nonspecific defense mechanisms

General defenses that everyone has, such as inflammation, skin chemicals, and phagocytosis.

Specific defense mechanisms

Defenses tailored to an individual based on previous disease exposure or vaccinations; involve cells that remember and attack pathogens.

Humoral immunity

B cells and antibodies that target pathogens.

Cellular immunity

T cells that directly attack infected cells.

Antigen specific

Immunity designed to target specific pathogens.

Systemic

Immunity that recognizes pathogens anywhere in the body.

Memory

Immunity that remembers pathogens and responds faster upon re-exposure.

Histamine

An inflammatory chemical that increases capillary permeability, allowing fluid to escape into interstitial spaces.

Basophils

A type of leukocyte that releases histamine and heparin.

Mast cells

Connective tissue cells that release histamine during inflammation.

Keratin

Tough protein in epidermis that strengthens skin and makes it waterproof.

Mucous membranes

Line body cavities open to the outside and provide protective barriers.

Enzymes (immune-related)

Destroy pathogens in body fluids such as gastric juice, tears, and saliva.

Acidic pH

Helps inhibit bacterial growth on skin and in body fluids.

Inflammation

A protective process causing redness, swelling, heat, and pain, recruiting immune cells to injury or infection sites.

Neutrophils

Short-term phagocytic white blood cells that respond during acute inflammation.

Fibrinogen

A plasma protein/clotting factor that forms a mesh around pathogens or injury sites to contain them.

Reticuloendothelial system (RES)

Macrophages distributed throughout the body that phagocytize pathogens and debris.

Macrophages

Phagocytic cells in tissues that engulf and destroy pathogens; part of the RES.