Ch. 51 The Immune System in Animals Flashcards
pathogen
disease-causing organism
(ie) bacteria, parasite, microbe, virus or prion
immune system
the system whose primary function is to defend the host organism against pathogens
- includes several types of cells (leukocytes)
- lymph nodes & thymus
organs of the immune system
1) lymph nodes
2) thymus
observations biologists investigated about how animals stay healthy
1) wounds usually heal even if they become infected
2) most people who contract a bacterial/viral illness eventually recover w/out medication
3) people who acquire bacterial in viral infections and recover frequently do not contract the same disease again
immunity
a resistance to or protection against disease-causing pathogens
- prevents individuals from contracting disease more than once
immunization
the conferring of immunity to a particular disease by artificial means
(ie) vaccination
vaccination
artificially producing immunological memory against a pathogen by introducing a weakened/altered pathogen to prime the body’s immune system so it fights later infections effectively
Edward Jenner
physician who observed milkmaids did not get smallpox b/c they were exposed to cowpox
innate immunity
a set of barriers to infection & generic defenses against broad types of pathogens
- immediate response
- involves many leukocytes
- often activate an inflammatory response
- ready to respond to foreign invaders @ all times
- nonspecific
- responds in the same way to all antigens
antigen
any foreign molecule (often a protein) that can stimulate an innate or adaptive response by the immune system
adaptive immunity
immunity to a particular pathogen or antigen
- based on interactions btwn specific immune system cells & a specific antigen
- B & T cells
- specific
- diverse
- memory
- self-nonself recognition
(aka) adaptive immune response
* we get this from our mom
types of immunity
1) innate immunity
2) adaptive immunity
characteristics of innate immunity
- occurs in all animals
- has both cell-mediated & secreted components
- rapid response
- broadly specific response against types of pathogens
- response does not vary when infections recur (no memory)
- born w/
characteristics of adaptive immune
- occurs only in vertebrates
- has both cell-mediated & secreted components
- slow response
- specific response against pathogen strains
- response is more rapid & efficient when infection recur (memory)
- learned
barriers to invasion/entry
1) non-specific physical/chemical defenses
2) innate immunity (natural)
3) adaptive immunity (acquired)
* if pass #3, you’re screwed, you will die
types of barriers in the animal kingdom
1) insects - armored body
2) soft-bodied animals - covered w/ mucus
3) human skin - dead cells filled w/ keratin
how does the human skin act as a barrier against invasions?
1) shingled dead layer of cells filled w/ keratin acts as a protective layer
2) skin covered w/ oil (fatty acids), which lowers pH, making it difficult for pathogens to grow
mucus
a proteoglycan-rich solution secreted by epithelial cells
- serves as a barrier to protect surfaces from infection
how are gaps in the body protected?
*excluding mucous layers
via wax & lysozyme
wax
a class of lipid w/ extremely long, saturated hydrocarbon tails - harder & less greasy than fats
lysozyme
an enzyme that digests bacterial cell walls
- innate immunity
- occurs in lysozomes of phagocytes
- secreted in saliva, tears, mucus & egg white
flu virus
contain enzyme on their surface that disrupts the mucous lining of the respiratory tract
- sialic acid (originated from chickens)
- cross species disease
cells involved in the innate immune response
1) leukocytes
2) mast cells
3) macrophages
4) neutrophils
how are innate immune response leukocytes alerted by the presence of foreign invaders?
antibodies bind to antigens, labeling them as invaders
- binding cites are only found in invaders, not host cells