Animals - Immunity

Parasite

organism that obtains nutrients by living/feeding on an organism of a different species

Pathogen

organism that causes disease in another organism

Immunity

ability of tissues in an organism to recognize and to defend against nonself invaders

What are the 2 categories of defense mechanisms?

innate immuntity, acquired inmmunity

Innate Immunity

"built it" mechanisms that do not depend on prior exposure

Acquired Immunity

aquired/adaptive immune response is highly specific, learned defense system that develops after exposure to pathogens or antigens

What are the innate defense mechanisms?

physical barriers, chemical barriers, phagocytosis, inflammation

Physical Barriers

Chemical Barriers

Phagocytosis

engulfment of a particle by a phagocyte or unicellular eukaryote

Inflammation

key component of innate immune responses, redness/heat/swelling, histamine is an organic nitrogenous compound produced by immune cells to fight invaders

What are the kinds of immune cells?

leukocyte, lymphocyte (T cells/B cells)

Leukocyte

white blood cells (w/o hemoglobin)

Where do many types of immune cells in vertebrates derive from?

bone marrow

T Cells

cytotoxic T cells destroy infected cells, helper T cells send signals that direct other immune cells to fight infection

B Cells

produce antibodies, plasma cells release antibodies in response to anitgens, memory cells remember particular antigens

Antibodies

Y shaped proteins produced by B cell lymphocytes to indentify and nuetralize invaders

Antigen

marker that tells your immune system whether something in your body is harmful or not

How does acquired immunity work?

recognition, response, remember

Recognition (Antigen Detection)

specialized cells engulf pathogens and present pieces of them to T cells

Response (Activation & Attack)

helper t cells activate b cells and cytotoxic t cells, b cells differentiate into plasma cells that produce antibodies, cytotoxic t cells identify and destroy infected cells

Remember (Immunological Memory)

some B cells turn into memory cells, stay in body for years allowing immune system to recognize and elimate the same pathogen rapidly if it returns

Major Histocompatibility Complec (MHC)

group of genes that code proteins that help immune cells recognize invaders from non-invaders

What happens when an immune system does not recognize itself?

it attacks itself

What kind of vertebrates is acquired immunity found in?

jawed vertebrates (gnathostoma)

Describe immunity in porifera.

archaeocytes

What phagocytes are present in invertebrates like cnidarians, annelids, mollusks, and others?

amoebocytes

What do bilaterian invertebrates use for phagocytosis?

hemocytes

Describe immunity in insects.

sophisticated innate system, hemocytes perform phagocytosis, antimicrobial peptides kill bacteria/fungi in hemolymph (blood),

Describe immune memory in insects.

(priming) non specific memory where previous exposure to a pathogen improves survival against future infections

Why are measles so scary?

immune amnesia: virus kills cells that protect the body from other diseases, leabing victims vulnerable to other infections for up to 3 years