micro bio exam 3

What are the symptoms of inflammation?

Redness, heat, swelling, pain, and loss of function.

What do histamine, prostaglandins, and kinins do in inflammation?

Histamine causes vasodilation and permeability. Prostaglandins intensify inflammation. Kinins attract phagocytes.

What are CD4 and CD8 cells also known as?

CD4 = Helper T cells, CD8 = Cytotoxic T cells.

What is the role of helper T cells?

Activate B cells, other T cells, and macrophages; coordinate immune response.

What is immunogenicity?

The ability of a substance to provoke an immune response.

Describe the structure of an antibody.

Y-shaped with two heavy and two light chains, variable and constant regions.

What are the parts of an antibody?

Fab (antigen-binding fragment), Fc (constant region), heavy and light chains.

What are the five different types of antibodies and their functions?

IgG: long-term immunity; IgA: mucosal defense; IgM: first responder; IgE: allergy/parasites; IgD: B cell activation.

What are the percentages of antibodies in the body?

IgG ~75%, IgA ~15%, IgM ~5-10%, IgE & IgD <1%.

Where can different antibodies be found?

IgG: blood; IgA: secretions (tears, saliva); IgM: blood/lymph; IgE: skin/mucosa; IgD: B cells.

What are the different types of T cells and their functions?

Helper T: activate immune cells; Cytotoxic T: kill infected cells; Regulatory T: suppress immunity; Memory T: provide memory.

How do cytotoxic T cells kill?

Release perforin and granzymes causing apoptosis in target cells.

What are the functions of natural killer cells, phagosome, neutrophil, monocyte, eosinophil, and basophil?

NK: kill infected cells; Phagosome: vesicle for digestion; Neutrophil: phagocytosis; Monocyte: precursor to macrophages; Eosinophil: fight parasites; Basophil: release histamine.

What do MAC, interferon, TNF, prostaglandins, leukotrienes, and interleukins do?

MAC: cell lysis; Interferon: viral resistance; TNF: inflammation/apoptosis; Prostaglandins: inflammation; Leukotrienes: bronchoconstriction; Interleukins: immune cell communication.

What are the stages in a death curve in a closed system?

Lag, log (exponential), stationary, death phases.

What happens at points A, B, C, and D in the death curve?

A: lag (adaptation), B: log (growth), C: stationary (equal growth/death), D: death (decline).

What are the first, second, and third lines of defense in the immune system?

1st: skin, mucous membranes; 2nd: inflammation, phagocytes; 3rd: T & B cells (adaptive immunity).

How do interferon, complement, lysozyme, transferrin, sebum, and cerumen protect the body?

Interferon: blocks viral replication; Complement: cell lysis; Lysozyme: digests bacterial walls; Transferrin: binds iron; Sebum/Cerumen: inhibit microbial growth.

What are the stages in phagocytosis?

Chemotaxis, adherence, ingestion, digestion, and exocytosis.

What is inflammation?

The body's response to injury or infection to eliminate cause and begin healing.

Outline the steps of inflammation.

1. Injury, 2. Chemical release, 3. Vasodilation, 4. Phagocyte recruitment, 5. Healing.

What is the difference between non-specific defense mechanisms and immune response?

Non-specific: general defense (innate); Immune: targeted response with memory (adaptive).

Define antibody-mediated and cell-mediated immunity.

Antibody-mediated: B cells produce antibodies; Cell-mediated: T cells attack infected or abnormal cells.

What do antibody-mediated and cell-mediated immunity fight off?

Antibody: extracellular bacteria/toxins; Cell-mediated: viruses, fungi, cancer cells, transplants.

Which cells are involved in cell- and antibody-mediated immunity?

Cell-mediated: T cells; Antibody-mediated: B cells and plasma cells.

What is an antigen?

Any molecule that stimulates an immune response.

What is a hapten?

A small molecule that becomes antigenic only when attached to a larger carrier.

What are different types of antigens?

Exogenous (outside body), endogenous (within cells), autoantigens (self).

What are complement proteins and where are they made?

Plasma proteins made in the liver that enhance immune responses.

What is immunological memory?

Ability of the immune system to respond faster on second exposure to an antigen.

What are antigen-presenting cells?

Cells that display antigens with MHC II to helper T cells.

Give examples of antigen-presenting cells.

Dendritic cells, macrophages, B cells.

What are resident flora, transient flora, commensals, and mutualistic organisms?

Resident: long-term microbes; Transient: temporary; Commensals: no harm/benefit; Mutualists: benefit host and microbe.

What does the normal flora do for the body?

Competes with pathogens, produces vitamins, stimulates immunity.

Why can only certain microorganisms live on the skin?

Skin is dry, acidic (pH ~5.5), salty, and has antimicrobial secretions.

Where do you find the largest population of microorganisms?

The large intestine (colon).

What is desquamation?

Shedding of skin cells, helping remove microbes.

What is chyme?

Partially digested food mixed with gastric secretions in the stomach.

What is peristalsis?

Wave-like muscle contractions moving food through the digestive tract.

What are tears and what is ciliary action?

Tears contain lysozyme to wash away microbes; Ciliary action moves mucus out of the respiratory tract.

List some body mechanisms that prevent organisms from attaching.

Mucus, cilia, saliva, tears, skin oils, normal flora.

Where does the embryo attach?

To the endometrium of the uterus.

How does a microorganism make you sick?

Entry, adherence, invasion, evasion, damage (infection steps).

What are virulence factors of microorganisms?

Toxins, capsules, enzymes, pili, flagella, adhesion molecules.

Which parts of the body have microorganisms and which are germ-free?

Have: skin, mouth, gut, vagina; Germ-free: blood, brain, lungs, internal organs.

What are gnotobiotic animals?

Animals raised in sterile conditions or with known microbes.

Differentiate between commensal and mutualistic relationships.

Commensal: one benefits, the other unaffected; Mutualistic: both benefit.

What is the pH of the skin and stomach?

Skin ~5.5; Stomach ~1.5–3.5 (very acidic).

How do you inhibit mycoplasmas?

Use antibiotics like tetracycline; they lack cell walls, so penicillin is ineffective.

What part of the body is sterile and what part has normal flora?

Sterile: internal organs, blood; Flora: skin, gut, mouth, vagina.

What characteristics of normal flora allow them to live on the body?

Adaptation to pH, nutrients, resistance to host defenses, biofilm formation.

Describe the bacteria found in the duodenum, jejunum, and ileum.

Duodenum: few due to bile/acidity; Jejunum: some Gram-positive; Ileum: more, including Gram-negative anaerobes.

Who first examined gnotobiotic animals?

Louis Pasteur and later researchers refined sterile animal techniques.

What does the normal flora do for your health?

Protects against pathogens, aids digestion, modulates immunity, produces vitamins.

What are the two types of cytotoxic or killer T cells?

Cytotoxic T cells (CD8+) and Natural Killer (NK) cells.

What is cell-mediated immunity and what does it target?

It involves T cells and targets viruses, fungi, cancer cells, and transplanted organs.

What is antibody-mediated immunity and what does it target?

It involves B cells and targets extracellular bacteria and toxins.

Do these immunities target viruses, fungi, bacteria, cancer cells, transplanted organs, and the RH factor?

Yes. Cell-mediated targets viruses, fungi, cancer, transplanted organs; antibody-mediated mainly targets bacteria and toxins. RH factor is a target in some antibody responses.

What are the steps of inflammation?

1. Injury, 2. Chemical release, 3. Vasodilation, 4. Phagocyte migration, 5. Repair.

What criteria define the immune response?

Specificity, memory, and self vs non-self recognition.

What is the antigenic determinant?

The specific part of an antigen that is recognized by antibodies (epitope).

What are the heavy and light chains of an antibody made of?

Proteins; heavy and light chains are polypeptides held by disulfide bonds.

What are IgA, IgG, and IgM, what are their percentages, where do they reside, and what do they do?

IgG (75%, blood, long-term immunity), IgA (15%, secretions, mucosal protection), IgM (5–10%, blood/lymph, first response).

Which antibody is most in circulation and which is the first produced during exposure?

IgG is most in circulation; IgM is the first made in response to infection.

Where are antigen-presenting cells found and what are their types?

Found in tissues, lymph nodes, and spleen. Types: dendritic cells, macrophages, B cells.

What are the stages in phagocytosis?

Chemotaxis, adherence, ingestion, digestion, exocytosis.

How long does phagocytosis take to kill something?

Minutes to hours depending on the pathogen.

What types of immunity exist and provide examples of each?

Naturally active: infection; Naturally passive: breast milk; Artificially active: vaccine; Artificially passive: antibody injection.

Where are fixed macrophages located and what are their names?

In tissues: Kupffer (liver), microglia (brain), alveolar (lungs), etc.

What is a neutrophil?

A fast-responding phagocyte; first at infection site.

What is a monocyte?

A precursor to macrophages and dendritic cells found in blood.

What is a macrophage?

A large phagocyte derived from monocytes; can present antigens.

What are natural killer cells?

Lymphocytes that kill infected or cancerous cells without MHC recognition.

Where are natural killer cells found?

Blood, spleen, liver, lungs.

What is the first type of blood cell to arrive at an infection?

Neutrophils.

What is the membrane attack complex (MAC) and what is its function?

A complex from complement proteins that forms pores in target cell membranes, causing lysis.

What is opsonization?

Coating of a pathogen by antibodies or complement to enhance phagocytosis.

What are the functions of the complement system?

Opsonization, inflammation promotion, and cell lysis via MAC.

Where do T cells and B cells mature?

T cells in the thymus; B cells in the bone marrow.

What is an antigen?

A substance that triggers an immune response.

What is a pathogen?

A disease-causing microorganism.

What is specific resistance?

Targeted immune response involving memory (adaptive immunity).

What is non-specific resistance?

General defenses like skin, fever, inflammation (innate immunity).

Define resistance.

The body's ability to fend off disease.

What is pathogenicity?

The ability of a microbe to cause disease.

What is susceptibility?

Lack of resistance to disease.

What is immunity?

Ability to resist infection or disease.

What is an epidemic?

Sudden disease outbreak in a community.

What is a pandemic?

Global disease outbreak.