Chapter 21 Flashcards
immune system exam 2
immunity
the ability of the body to defend itself against foreign antigens
antigens
used by immune cells to recognize self vs non self
what are the 2 intrinsic systems
- innate defenses
- adaptive defenses
innate defenses
nonspecifc
built-in
has physical barries and cells/chemicals
initiated very quickly
surface barries
physically block pathogens from entering
what are the 2 surface barries
skin and mucous membranes
skin
keratin: tough protein on the surface of the skin that is resistant to weak acids, weak bases, and bacterial enzymes
acid mantle: sweat and sebum are acidic,
bactericidal: prevent pathogen growth
mucus
traps microorganisms in respiratory/ digestive tract
mucous membranes
lines body cavities that lead into and out of the body
cilia
beat back and forth and get rid of microorganisms stuck in mucus in respiratory tract
acid mantle
stomach: secretes gastric juices 1.5-3 pH bacteria cannot survive
vagina: acidic in nature, prevents bacterial/fungal growth
tears and saliva
contains lysozymes: kill bacteria
tears: clean out eyes
saliva: bring microorganisms into the stomach
urine
acidic in nature: get rid of microorganisms during urination
cells and chemicals: innate defense
used when surface barries are breached
pattern recognition receptor
on innate system cells
proteins that recognize pathogens by finding specific molecules not present on human cells
types of innate defense cells
natural killer cells
phagocytes
- macrophages
- neutrophils
Natural killer cells
target virus-infected cells and cancerous cells
nonspecific
directly contact cells and induce apoptosis
release perforins
what do perforins do in NK cells
create pores in the cell membrane
allow proteases to enter which will induce apoptosis
phagocytes
neutrophils and macrophages
phagocytosis: engulfs cells and destroys them
macrophages
large and voracious
free: capable of traveling through tissue to search for pathogens
fixed: permanent location in tissue of an organ
neutrophils
neutrophils: become phagocytic upon encountering a pathogen
can also use defensins : create pores on cell membrane - allow water to enter cell and induce lysis
innate chemicals
antimicrobial proteins
antimicrobial proteins
proteins that can directly kill pathogens or interfere w their reproduction
interferons or complement
normal body temp
98.6 F
interferons
released by infected cells to protect noninfected cells
diffuse into cell and creates proteins to degrade viral DNA
complement
group of 20 plasma proteins synthesized by the liver
what are the roles of complements
activation: massive release of inflammatory chemicals
stimulate phagocytes to clear debris
kill/lyse bacteria
pyrogens
released by macrophages and leukocytes : fire starter
reset hypothalamus to raise body temperature
fever
body wide systemic defense to a pathogen : incresase nody temp
low grade fever
99-100.4 F
what are the benefits of fever
- causes spleen/liver to store more Fe; cannot be used by bacteria for growth
- increase metabolic rate of tissue cells- increase repair
adaptive defenses
more specific
good: more specialized defenses
bad: take longer to initiate than innate system
two features of adaptive defenses
humoral immunity
cellular immunity
humoral immunity
antibodies present in the body fluid (humors)
circulate freely and inactivate cells for destruction
B lymphocytes
cellular immunity
when lymphocytes directly defend the body
kill target cells
release chemicals that increase the inflammatory response
active macrophages
differences between adaptive and innate
uses lymphocytes
adaptive more specific
systemic
has memory
antigens
any substance that can mobilize the adaptive system
complete antigens
immunogenic: can stimulate lymphocyte proliferation and generate immune response
incomplete antigens
haptens: must be bound to a protein carrier for immune response to occur
if non self antigen not bound to protein carrier immune response wont occur
antigenic determinants
to begin an immune response, antibodies and lymphocytes must bind to antigenic determinant
self antigens
antigens that belong to the body
major histocompatibility complex (MHC)
glycoprotein found on the surface of our body cells
cells of the adaptive system
lymphocytes and antigen presenting cells
lymphocytes
b cells and t cells
must mature before immune response can occur
5 steps of maturation for lymphocytes
originate from hematopoietic stem cells
education
seeding and circulation
antigen exposure
proliferation
education of cells
immunocompetence: lymphocyte learns to recognize a single antigen to act against it
form a specific receptor
self tolerance : learn self vs nonself
seeding and circulation
leave the bone marrow and thymus and colonize secondary lymphoid organs
antigen exposure
first encounter leads to clonal selection
lymphocytes create clones w same antigen specificity
proliferation
activated lymphocyte proliferates to form lymphocytes w the same receptor
antigen presenting cells
cells engulf cells and display some of its fragments
3 types of APC
dendritic cells
macrophages
b cells
b lymphocytes and humoral immunity
involves the production of plasma cells that produce and secrete antibodies for a specific antigen
process of producing antibodies
- primary response
- clonal selection
- clones can differentiate into 2 cells
- secondary response and immunological memory
active humoral immunity
b cells encounter antigen, produce plasma cells and antibodies to act against them
active humoral immunity 2 ways
- naturally acquired: bacterial or virus infection occurs in the body
- artificially acquired: use of vaccines
passive humoral immunity
antibodies are supplied to the body rather than produced by it
passive humoral immunity 2 ways
- natural: antibodies are passed from the mother to the fetus
- artificially: antibodies supplied by an immune donor
antibodies
each type of antibody has an antigen binding site
also called immunoglobulins
IgM
first class that is secreted by plasma cells
IgA
found in the body secretions
IgD
functions as B cell antigen receptor
IgG
most abundant antibody
IgE
release histamine: mediates inflammation and allergic reaction
Antibody Action steps
- neutralization
- agglutination
- precipitation
- complement activation
