Ch. 16 Innate Immunity: Nonspecific Defenses of the Host

Immunodeficiency

hyporeactivity

systemic autoimmunity

hypereactivity

white blood cells

counts measure leukocytes in the blood

high WBC

indicate bacterial infections, autoimmune diseases, or side effects of medications

Low WBC

indicate viral infections, pneumonia, autoimmune diseases, or cancers

immunity

ability to ward off disease

susceptibility

lack of resistance to disease

innate immunity

defenses against any pathogen, rapid, present at birth

adaptive immunity

immunity or resistance to a specific pathogen; slower to respond, has memory component

first line of defense

Skin and mucous membranes

dermis

 inner portion made of connective tissue

epidermis

outer portion made of tightly packed epithelial cells containing keratin, a protective protein

skin shedding and dryness

 inhibits microbial growth

mucous membranes

epithelial layer that lines the gastrointestinal, respiratory, and genitourinary tracts

mucus

viscous glycoproteins that trap microbes and prevents tracts from drying out

lacrimal apparatus

drains tears, washes eye

ciliary escalator

transports microbes trapped in mucus away from the lungs

earwax

prevents microbes from entering the ear

urine

cleans urethra via flow

vaginal secretion

move microorganisms out of the vaginal tract

sebum

forms a protective film and lowers the pH(3-5) of skin

lysozyme

in perspiration, tears, saliva, and urine destroys bacterial cell walls

gastric juice

low pH (1.2-3.0) destroys most bacteria

vaginal secretion pH

low pH (3-5) inhibits microbes

Normal microbiota

compete with pathogens via microbial antagonism

commensalism

one organism benefits while the other is harmed

probiotic

 live microbial cultures administered to exert a beneficial effect

second line of defense

Blood

blood

cells and cell fragments suspended in plasma

erythrocytes

red blood cells

leukocytes

white blood cells

platelets

blood clotting factor

hematopoiesis

creation of red bone marrow stem cells

granulocytes

WBC with granules in their cytoplasm that are visible with a light microscope

neutrophils

phagocytic; work in early stage of bacterial infection

Basophils

release histamine; work allergic responses

Eosinophils

phagocytic; toxic against parasites and helminths

agranulocytes

WBCwith granules in their cytoplasm that are not visible with a light microscope

monocytes

matures into macrophages in tissues where they are phagocytic

dendritic cells

found in the skin, mucous membranes, and thymus; phagocytic

lymphocytes

T cells, B cells, and NK cells; play a role in adaptive immunity

NK cells

destroy target cells by cytolysis and apoptosis cell-mediated immunity

T cells

cell-mediated immunity

B cells

produce antibodies

neutrophil development

metamyelocyte, juvenile or band form, staff or stab form, segmented neutrophil

phago

from the greek meaning to eat

cyte

from the greek, meaning cell

fixed macrophages

are residents in tissues and organs

free macrophages

roam tissues and gather at sites of infection

chemotaxis

chemical signals attract phagocytes to microorganisms

adherence

attachments of a phagocyte to the surface of the microorganism

TLRs

toll-like receptors

toll-like receptors

on host cells attached to pathogen-associated molecular patterns, induce the release of cytokines from the host cell that regulates the intensity and duration of immune responses

PAMPs

pathogen-associated molecular patterns

ingestion

opsonization

opsonization

microorganism is coated with serum proteins, making ingestion easier

digestion

microorganism is digested inside a phagolysosom

phagocytosis

cell eats a bacteria by engulfing it, breaking it down, and discharging it as waste

ways to evade phagocytosis

inhibit adherence, kill phagocytes, lyse phagocytes, escape phagosome, prevent phagosome/ lysosome fusion, survive in phagolysosome

signs and symptoms of inflammation

redness, swelling(edema), pain, and heat

function of inflammation

destroys injurious agents or limits its effects on the body, repairs and replaces tissues damaged by the injurious agent

acute phase proteins

activated by inflammation by the liver

effects of acute phase proteins

Vasodilation and increased permeability of blood vessels, histamine, kinins, prostaglandins, leukotrienes, cytokines

migration

sticking of phagocytes to blood vessels in response to cytokines at the site of inflammation

diapedesis

phagocytes squeeze between endothelial cells

tissue repair

cannot be completed until all harmful substances are removed or neutralized, stroma is supporting connective tissue, parenchyma is functioning part of the tissue that is repaired

fever

abnormally high body temperature(37*C)

cytokines

cause hypothalamus to release prostaglandins that reset the hypothalamus to a higher temperature

physiological changes

blood vessels constrict, shivering

serum proteins

produced by the liver that assist the immune system in destroying microbes

complement activation

act in a cascading process

cytolysis

activated complement proteins created a membrane attach complex

MAC

membrane attach complex

opsonization

promotes attachment of a phagocyte to a microbe

inflammation

activated complement proteins bind to mast cells, releasing histamine

regulation of complement

regulatory proteins readily break down complement proteins, minimizing host cell destruction

link of disease and complement

lack of complement proteins causes susceptibility to infections

capsules

prevent complement activation

cytokines

have antiviral activity

IFN-a and IFN-B

produced by cells in response to viral infections; cause neighboring cells to produce antiviral proteins(AVPs) that inhibit viral replication

IFN-y

causes neutrophils and macrophages to kill bacteria

antiviral action of alpha and beta interferons

interferons inhibit the further transcriptions or translation of viral RNA so no more viral replication can occur