innate immune system - They are always available to provide rapid responses to protect us against disease

First-line defenses - Skin, mucous membranes, and certain antimicrobial substances

Second-line defenses - They include proteins that produce inflammation, fever that enhances cytokine activity, and phagocytes and natural killer

adaptive immune system

Third-line defenses - Include lymphocytes that target specific pathogens for destruction when the second-line defenses don’t contain infections.

It includes a memory component that allows the body to more effectively respond to that same pathogen in the future

Differential white blood cell count - Breaks down the white blood cell count further, identifying the percentages of eosinophils

• High White Blood Cell Counts - his typically occurs when the patient battles a bacterial infection

• Low White Blood Cells Counts - Low white blood cell counts may result from viral infections or pneumonia.

Immunity - ability to ward off disease caused by microbes or their products and to protect against environmental agents such as pollen, chemicals, and animal dander

• Susceptibility - Lack of immunity

Innate immunity - Refers to defenses that are present at birth. They are always available to provide rapid responses to protect us against disease

Adaptive immunity - Is based on a specific response to a specific microbe once a microbe has breached the innate immunity defenses, Involves; T cells and B cells

Toll-like receptors (TLRs) - detect conserved molecular patterns on pathogens and initiate an immune response. (PAMPS) . induce the defensive cells to release chemicals called cytokines.

Cytokines - are proteins that regulate the intensity and duration of immune responses

Treponema pallidum - A pathogen that can thrive on the moist secretions are able to penetrate the membrane if the microorganism is present in sufficient numbers

Lacrimal apparatus - A group of structures that manufactures and drains tears

Saliva - Helps dilute the numbers of microorganisms and wash them from the surface of the teeth and the mucous membrane of the mouth

Ciliary escalator - Keeps the mucus blanket moving toward the throat at a rate of 1 to 3 cm per hour; coughing and sneezing speed up the escalator

Hairs and earwax/cerumen - Which help prevent microbes, dust, insects, and water from entering the ear

Urine - Which cleanse the urethra which prevents microbial colonization in the genitourinary tract

Peristalsis - Is a series of coordinated contractions that propels food along the gastrointestinal tract

Defecation - Mass peristalsis of large intestinal contents into the rectum

Vomiting and/or diarrhea - mechanism when microbial toxins is present in the gastrointestinal tract

CHEMICAL FACTORS

Sebum - oil found in the glands of the hair, Prevents hair from drying and becoming brittle

Isotretinoin - inhibitor for sebum production, A derivative of vitamin A

Perspiration - sweating, regulates temperature

Lysozyme - An enzyme capable of breaking down cell walls of gram-positive bacteria Breaks chemical bonds on peptidoglycan, which destroys the cell walls.

• Found in tears, saliva, nasal secretions, tissue fluids, and urine,

Helicobacter pylori - Its growth initiates an immune response that results in gastritis and ulcers

NORMAL MICROBIOTA AND INNATE IMMUNITY

Commensalism - One organism uses the body of a larger organism as its physical environment and may make use of the body to obtain nutrients

• One organism benefits while the other is unaffected

• Most microbes that are part of the commensal microbiota are found on the skin and in the gastrointestinal tract

Probiotics - Are live microbial cultures applied to or ingested that are intended to exert a beneficial effect

Lactic acid bacteria - Colonize the large intestine, the lactic acid and bacteriocins they produce can inhibit the growth of certain pathogens

SECOND LINE OF DEFENSE - When microbes penetrate the first line of defense, they encounter a second line of defense that includes defensive cells, such as phagocytic cells; inflammation; fever; and antimicrobial substances

Hematopoiesis - formation of red blood cells

Leukocytes are divided into two main categories based on their appearance under a light microscope

GRANULOCYTES - presence of large granules in their cytoplasm that can be seen with a light microscope after staining

• Neutrophils - Are highly phagocytic and motile, are active in the initial stages of an infection

• Basophils - release substances, such as histamine, that are important in inflammation and allergic responses

• Eosinophils - Kill certain parasites, such as helminths

AGRANULOCYTES - Also have granules in their cytoplasm, but the granules are not visible under the light microscope after staining

• Monocytes - enter body tissues, and mature into macrophages

• Dendritic cells - destroy microbes by phagocytosis and initiate adaptive immune responses

• Lymphocytes - Include Natural killer cells, T cells, and B cells

• Natural killer (NK) cells - Attack any body cells that display abnormal or unusual plasma membrane proteins

Perforin - which inserts into the plasma membrane of the target cell and creates channels in the membrane ( murag tubo e sud sa cell)

Granzymes - protein-digesting enzymes that induce the target cell to undergo apoptosis

Leukocytosis - Increase in the total number of white blood cells during bacterial infections as a protective response to combat the microbes

Phagocytosis - Is the ingestion of a microorganism or other substance by a cell

ACTIONS OF PHAGOCYTIC CELLS

THE MECHANISM OF PHAGOCYTOSIS

1. Chemotaxis - Is the chemical attraction of phagocytes to microorganisms.

2. Adherence - Is the attachment of the phagocyte’s plasma membrane to the surface of the microorganism or other foreign material

   • Opsonization - A coating process of microorganism with certain serum proteins that promote attachment of the microorganism to the phagocyte so they can be readily phagocytized

3. Ingestion - The plasma membrane of the phagocyte extends projections called pseudopods that engulf the microorganism

4. Digestion - Next, the phagosome pinches off from the plasma membrane and enters the cytoplasm, where it contacts lysosomes that contain digestive enzymes and bactericidal substances

   • Lysozyme - hydrolyzes peptidoglycan in bacterial cell walls

INFLAMMATION

Acute inflammation - inflammation ● The signs and symptoms develop rapidly and usually last for a few days or even a few weeks

Chronic inflammation - The signs and symptoms develop more slowly and can last for up to several months or years

Increased permeability - Permits defensive substances normally retained in the blood to pass through the walls of the blood vessels and enter the injured area

• Kinins - they play a role in chemotaxis by attracting phagocytic granulocytes, chiefly neutrophils, to the injured area

• Prostaglandins - intensify the effects of histamine and kinins and help phagocytes move through capillary walls.

• Leukotrienes - Cause increased permeability of blood vessels and help attach phagocytes to pathogens

Chemokines - Are cytokines that are chemotactic for phagocytes and T cells and thus stimulate both the inflammatory response and an adaptive immune response

TISSUE REPAIR

Stroma - Is the supporting connective tissue

Parenchyma - Is the functioning part of the tissue

FEVER - Abnormally high body temperature,

Cytokines interleukin-1 - These cytokines cause the hypothalamus to release prostaglandins that reset the hypothalamic thermostat at a higher temperature

Interleukin-1 - Helps step up the production of T cells

Crisis - Heat-losing mechanism such as vasodilation and sweating occurs

ANTIMICROBIAL SUBSTANCES

Classical Pathway - It is initiated when antibodies bind to antigens

Alternative Pathway - Activated by contact between certain complement proteins and a pathogen

Lectin Pathway - When macrophages ingest bacteria, viruses, and other foreign matter by phagocytosis, they release cytokines that stimulate the liver to produce lectins, proteins that bind to carbohydrates

Cytolysis - disruption of cells

Opsonization - Or immune adherence, promotes attachment of a phagocyte to a microbe. This enhances phagocytosis

Interferons

Interferons - Were originally named for one of their functions: the ability to interfere with viral infections in host cells

Alpha interferon (IFN-a) and Beta interferon (IFN-b) - Inhibit viral replication and activate immune cells like natural killer (NK) cells and macrophages.

Gamma interferon (IFN-g) - Plays a key role in activating macrophages and enhancing the immune response against pathogens. Slows the progression of multiple sclerosis (MS) and lessens the frequency and severity of MS attacks

ADAPTIVE IMMUNITY

Vaccination - A procedure that harnesses the adaptive immune response

Immunoglobulin - Antibodies recognize and combat foreign molecules called antigens, Another term for antibodies

Valence - The number of antigen-binding sites on an antibody

Monomer - Simplest structure