Ch. 18 Immune System Flashcards Preview

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Flashcards in Ch. 18 Immune System Deck (74):
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Pathogens

Disease causing organisms. Can be viruses, bacteria, and eukaryotic

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Contagious

Pathogen can be spread from one organism to another

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Infectious

Pathogen finds tissue inside the body that will support it's growth

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Parasites

Organisms obtain nutrients and shelter required for growth and development from a different organism without contributing to the survival of the host

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Microbes

Only seen under microscope. Microscopic organisms

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Bacteria

Tiny, prokaryotic, single celled organisms. Can be bacilli (rod shaped), cocci (spherical) or spirochetes (spiral).

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Bacteria structure

Lack nucleus. Nucleoid region has double stranded circular DNA chromosome
Contain plasmids
Surrounded by cell wall
Cell wall surrounded by capsule
Have flagella and pili
Reproduce by binary fission

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Plasmids (bacteria structure)

Circular extra chromosomal DNA. Can carry genes that protect bacteria against antibiotics

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Capsule (bacterial structure)

Help bacteria attach to tissues. Protect against immune cell attack

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Flagella (bacteria structure)

Used for movement

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Pili (bacteria structure)

Used to attach to one another and pass genes

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Binary fission

One parent cell copies DNA and splits into 2 identical daughter cells. Can reproduce rapidly under favorable conditions (double population in 20 mins)

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Bacterial diseases

Anthrax, botulism, E. coli, tetanus, and staph

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Viruses

Not considered living: can't replicate without host and is not composed of cells.
Once in host cell, virus replicates genome and uses hosts to ribosomes and amino acids to make viral proteins for new capsids and envelopes. Once assembled, daughter viruses leave cel and move to other cells to replicate and spread disease

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Genome (virus structure)

Genetic material can be RNA or DNA, double or single stranded, linear or circular

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Capsid (virus structure)

Protein coat surrounding virus. Removed once inside host cell

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Viral envelope (virus structure)

Additional structure outside capsid. Derived from cell membrane of host with its own proteins added. Attached to cells at protein receptors on host

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Latent virus

Enters state of dormancy and doesn't reproduce (herpes virus)

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Viral diseases

Common cold, hepatitis, influenza, and west Nile

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Eukaryotic pathogens

Single celled protozoans. Spread by water or food contaminated with animal feces

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Eukaryotic diseases

Giardiasis, malaria, schistosomiasis, tape worm, athletes foot/jock itch

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Prions

Normal occurring protein produced by brain cells

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Spongiform encephalopathy

Misfolded prions. Nerve cells in brai. Get clogged with these misfolded prions, causing them to misfire and stop functioning. The cell then bursts and frees the misfolded prions. They then find healthy prions and refold them. Causes empty space in brain and produces sponge like characteristic. Have no DNA or RNA and resist degradation. May be spread by eating meat containing misfolded proteins

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Direct contact

Touching infected organism

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Indirect contact

Contacting contaminated object

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Vector borne

Transmission through vector

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Vector

Organisms that carry disease causing microorganisms from one host to another

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Inhalation

Pathogens breathed in from air

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Ingestion

Eating contaminated foods

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First line of defense

Skin and mucous membranes. Nonspecific defense

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Nonspecific defenses

Don't distinguish one pathogen to another

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Skin

1st line. Physical barrier. Sheds and takes pathogens with. Low pH to repel microorganisms. Glands in skin secrete enzyme to break down bacteria (tears and saliva)

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Mucous membranes

1st line. Line resp, dig, ur, and repro tracts. Secrete mucus that traps pathogens and can be sneezed or excreted away

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Second line defense

WBCs, inflammation, defense proteins, and fever. Nonspecific

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White blood cells

2nd line. Phagocytes that engulf and digest invaders indiscriminately.
Macrophages
Natural killer cells

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Macrophages

Phagocytes that circulate in lymphatic fluid, cleaning up dead and damaged cells. Destroy by extending pseudopodia, grabbing, and engulfing. Enzymes inside break it down and release chems to stimulate production of more WBCs. Mostly occurs in lymph nodes. If invader is too large, other WBCs cluster round and secrete digestive enzymes to irritate or destroy. Often protozoans or worms

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Natural killer cells

Non soecific WBCs that attack tumor cells and virus invaded body cells. Release chems that break plasma membrane of targets and cause them to burst. Accumulate at site of infection causing pus, if it can't be releived, body walls it off wit tissue and create access

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Inflammation

2nd line. Reaction that produces redness, warmth, swelling, and pain. Damages cells release chems that stimulate histamines

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Histamines

Promotes vasodilation near injury. Enables more WBCs to arrive at site for cleanup. Extra blood flow brings O2 and nutrients for healing, but also increases swelling, redness, and warmth.

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Defense proteins

2nd line. Interferons. Proteins produced by virus infected cells to help uninfected cells stimulate production of proteins that inhibit viral reproduction.
Complement proteins

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Complement proteins

Help other defense mechanisms. Coat surfaces if microbes to aid phagocytes, poke holes on membrane to break them apart, or increase inflammatory response

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Fever

2nd line. Temp above 97-99F. Macrophages release chem pyrogens as weapons

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Pyrogens

Increase temp to decease bacterial growth and increase metabolism to e pair quickly and slow pathogen. When infection is controlled, macrophages stop releasing pyrogens and temp returns to normal.

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Third line of defense

Lymphocytes. Specific defense

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Specific defense

Attack specific microorganisms

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Lymphocytes

Travel through blood and attack specific microorganisms. Response triggered by proteins and carbs on surface of pathogens or infected cells. Concentrated in spleen and lymph nodes. Display specificity and recognize through antigen receptors. Produced from stem cells in bone marrow (100 mil/day)
B lymphocytes
T lymphocytes

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Antigens

Foreign molecules that stimulate immune response. Triggers enhanced production of B and T cells

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B lymphocytes (B cells)

Recognize and react to free living organisms like bacteria and their toxins. Secrete antibodies (proteins) that bind to and inactive antigens. Mature in bone marrow.

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T lymphocytes (T cells)

Recognize and react to body cells gone awry (cancer cells or cells invaded by viruses). Respond to implanted tissue and larger organisms like fungi and worms. Don't produce antibodies, attack directly. Move from bone marrow and mature in thymus

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Antigen receptors

Presence if proteins that fit perfectly to foreign molecule and binds to it. Can be attached to surface of lymphocyte (t cells and B cells) or secreted by lymphocytes (b cells)

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Antibodies

Found in lymph, intestines, tissue fluids, and breast milk

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Passive immunity

Antibodies passed through breast milk from mother to child. Lasts only as long as the antibodies live in blood

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Active immunity

Production if antibodies to combat infection for lifetime after antigen exposure

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Allergy

Immune response without presence of a pathogen

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Antigen diversity

B and T cells rearrange their DNA. Each unique arrangement encodes a different receptor protein. Once synthesized, they move to surface of cell and act as antigen receptors. Gives unlimited variety from small pool of genes

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Self vs. non self

Lymphocytes are tested to see if they react to self proteins. If they do, they are eliminated, of they don't, they are allowed to mature. Protects against autoimmune disease

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Autoimmune disease

When self testing fails and lymphocytes have antigen receptors for body's proteins. Causes immune system to attack healthy cells

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Multiple sclerosis

T cells specific for protein in nerve cells attack brain

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Insulin dependant diabetes

T and B cells attack cells that produce hormone in pancreas

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Humoral immunity

Use of memory cells, clinal populations, antibody-antigen complexes, complement proteins, and agglutination. Makes vaccinations possible

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Memory cell

Exact copy with same antibodies of B cell made after binding to antigen.

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Clonal population

Lots if memory cells that aid in overcoming the infection. Some remain and recognize antigen in future.

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Antibody-antigen complex

When antibody binds to antigen. Marks pathogen for phagocytes and degradation by complete proteins causing lysis of foreign cells

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Compliment proteins

Circulate body inactive until they bind to surface of microorganisms and become active

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Agglutinate

When pathogens and attached antibodies clump together making them unable to infect other cells.

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Vaccination

Injections of components of disease causing organisms. Creates clonal population for specific pathogen that will be prepare for a real infection

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Cell mediated immunity

T cells respond to infection by directly attacking and undergoing rapid cell division to produce memory cells.
Cytotoxic T cells
Helper T cells

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Cytotoxic T Cells

Stack and kill cells infected with virus. Recognize the viruses proteins as foreign, bind, and destroy entire cell. Done by releasing chem to break down plasma membrane then break cel down before the virus replicates

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Helper T Cells

Also called T4 cells. Boosters. Detect invaders and alert b and T cells that infection is occurring. Secrete interleukin 2

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Interleukin 2

Increases level of cytotoxic T cell response

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AIDS

Caused by HIV. HIV kills or disables helper T cells and causes deficient immune response . Patients often become ill from opportunistic infections

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Opportunistic infections

Only occur when opportunity arises die to weakened immune response

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No immune response to prions

Because they are refolded versions of the normal protein. Body still recognizes as self.

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Preventing misfolded prions and spongiform encephalopathy

Can't feed meat and bone meal. No John risk materials used in food or cosmetic products