BIO3 - Chapter 16

Innate Immunity Nonspecific Defenses of the Host

susceptibility

lack of resistance to a disease

immunity

ability to ward off 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

what do white blood cell counts measure

leukocytes in the blood

what do high WBC counts indicate

bacterial infections, autoimmune disease, or side effects of medications

what do low WBC counts indicate

virla infections, pneumonia, autoimmune diseases, or cancers

components of the first line of defense

skin, mucous membranes, normal microbiota

physical factors in first line of defense

barriers to entry or processes that remove microbes from the body’s surface

chemical factors in the first line of defense

chemicals inhibit or destroy microbial growth

dermis

part of the skin, inner portion made of connective tissue

epidermis

part of skin, outer portion made of tightly packed epithelial cells containing keratin

keratin

a protective protein

what are mucous membranes

layers that line the gastrointestinal, respiratory, and genitourinary tracts; they secret mucus

significance of mucus secretion

trap microbes & prevent tracts from drying out

significance of lacrimal apparatus

tears wash away microbes; washes eyes

significance of ciliary escalator

microbs trapped in mucus are transported away from the lungs

significance of earwax

prevents microbes from entering the ear

saliva significance

washes microbes off

urine and vaginal secretion method

flows out

all physical factors of the first line of defense

skin & mucous membranes

lacrimal apparatus

ciliary escalator

earwax

saliva

urine

vaginal secretions

sebum

produced by oil glands of the skin; oily substance

what does the skin secrete

fatty acids & lactic acids; low pH

result of sweat glands

perpiration

where is lysozyme found

perspiration, tears, saliva, urine

what do the glands of the stomach produce

gastric juice; low pH

what type of factor are vaginal secretions

chemical factors

list of all chemical factors in the first line of defense

sebum

fatty acids & lactic acids

perspiration

kysozyme

gastric juice

vaginal secretions

normal microbiota

compete w pathogens via microbial antagonism (competitive exclusion)

how is the normal microbiota helpful in the defense system

competitive advantage for space & nutrients

prod substances harmful to pathogens

alter conditions that affect pathogen survival

commensalism

one organism benefits while the other is unharmed

probiotics

live microbial cultures administered to exert a beneficial effect

components of the second line of defense

phagocytic cells

inflammation

fever

antimicrobial substances

formed elements in blood

red blood cells, white blood cells, platelets

types of white blood cells (leukocytes)

granulocytes & agranulocytes

granulocytes

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

types of granulocytes

neutrophils, basophils, eosinophils

neutrophils

neutral-love, phagocytic; work in early stages of infections, one of the first responders to infections, 60-70% of WBC

basophils

base-love, 0.5-1% of WBC, prod histamine, work in allergic responses

eosinophils

acid-loving, 2-4% of WBC, kill parasites

agranulocytes

leukocytes with granules in their cytoplasm that aren’t visible with a light microscope

types of agranulocytes

monocytes, dendritic cells, lymphocytes

monocytes

3-u% of WBC, respond quickly to infection, develop into macrophage, phagocytosis

dendritic cells

deried from monocytes, phagocytosis, found in the skin, mucous membranes, & thymuc; phagocytic

lymphocytes

20-50% of WBC, play a role in adaptive immunity

lymphocytes examples

natural kill cells, t cells, b cells

natural killer cell function

destroy target cells

t cell function

cell-mediated immunity

b cell function

prod antibodies

phagocytosis

ingestion of microbes or particles by a cell, performed by phagocytes

first step when an infection occurs

both granulocytes (especially neutrophils) & monocytes migrate to the infected area

what do monocytes develop into

large macrophages

fixed macrophages

residents in tissues & organs

wandering macrophages

roam tissues & gather at sites of infection

steps in phagocytosis

chemotaxis

adherence

ingestion

digestion

discharge

what are chemotaxis

chemical attraction

ways microbes evade phagocytosis

inhibit adherence

kill phagocytes

lyse phagocytes

escape phagosome

prevent phagosome-lysosome fusion

survive in phagolysosome

inflammation

damage to the body’s tissues triggers a local defensive response

effects of inflammation

redness, pair, heat, swelling, loss of function

2 types of inflammation

acute inflammation & chronic inflammation

function of inflammation

destroy the injurious agents

limit the effects on the body

repair or replace tissue damage

how does inflammation work

inflammation activates acute-phase proteins by the liver that cause vasodilation & increased permeability of blood vessels

acute-phase proteins

histamine

kinins

prostaglandins

leukotrienes

cytokines

process of inflammation

vasodilation & increased permeability of blood vessel

phagocyte migration

phagocytosis & tissue repair

vasodilation

dilation (increase in diameter) of blood vessel

purpose of vasodilation

increase blood flow to the damaged area

effects of vasodilation

cause redness & heat associated with inflammation

significance of increased permeability in inflammation

permits defensive substances normally retained in blood to pass through the walls of the blood vessel & enter the injured area

what is edema

accumulation of fluid (swelling)

what is margination

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

diapedesis

phagocytes squeeze between endothelials cells of blood vessels

what is fever

abnormally high body temp

hypothalamus significance

body’s “thermostat” located in the brain normally set at 37C, releases prostaglandins that reset the hypothalamus to a high temp

significance of chills/shivering

sign of body increseing rate of metabolism & temp, skin remains cold, indicates body temp is rising

body temperature when infection subsides

heat-losing mechanisms (vasodilation & sweating) go into operation: skin becomes warm & person begins to sweat, indicates body temperature falls

advantage of fever

increase transferrins

increase IL-1 activity

prod interferon

significance of transferrins

protein that grabs free iron before microbes do

IL-1 activity significance

help prod T-cells which fight bacteria

interferon significance

antiviral protein

disadvantages of fever

tachycardia

acidosis

dehydration

high fevers can be fatal

what is tachycardia

rapid heart rate

what is acidosis

too much acid in the body because of chemical production

list of antimicrobial substances

complement system

interferons

iron-binding proteins (transferrins)

antimicrobial peptides (short protein)

what is the complement system

defensive system consisting of over 30 proteins produced by the lived & found circulating in the blood serum & within tissues throughout the body

activation of complement system

serum proteins activated in a cascade

activated by antigen-antibody reaction or proteins C3, B, D, P and a pathogen

C3b significance

causes opsonization

C3a + C5a significance

cause inflammation

C5b + C6 + C7 + C8 + C9 significance

cause cell lysis

effects of complement activation

opsonization or immune adherence

membrane attack complex

attract phagocytes

what does opsonization or immune adherence mean

enhanced phagocytosis

what does membrane attack complex mean

cytolysis

what are the pathways to complement activation

classical, alternative, & lectin

classical pathway activation

binding to antigen-antibody complex

alternative pathway of activation

B,D,P of surface of a microbe

lectin pathway of activation

lectin binds to an invading cell

capsule role in evading complement

prevent C activation

curface lipid-carbohydrates in complement evasion

prevent membrane attack complex (MAC) from forming

how is C5a impacted in complement evasion

enzymativ digestion of C5a

what do INF-A & INF-B do

cause cells to prod antivial proteins that inhibit viral replication

what does gamma IFN do

cause neutrophils & macrophages to phagocytize bacteria