Ch. 18 Immune System Flashcards
Contagious
Pathogen can be spread from one organism to another
Pathogens
Disease causing organisms. Can be viruses, bacteria, and eukaryotic
Infectious
Pathogen finds tissue inside the body that will support it’s growth
Parasites
Organisms obtain nutrients and shelter required for growth and development from a different organism without contributing to the survival of the host
Microbes
Only seen under microscope. Microscopic organisms
Bacteria
Tiny, prokaryotic, single celled organisms. Can be bacilli (rod shaped), cocci (spherical) or spirochetes (spiral).
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
Plasmids (bacteria structure)
Circular extra chromosomal DNA. Can carry genes that protect bacteria against antibiotics
Capsule (bacterial structure)
Help bacteria attach to tissues. Protect against immune cell attack
Flagella (bacteria structure)
Used for movement
Pili (bacteria structure)
Used to attach to one another and pass genes
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)
Bacterial diseases
Anthrax, botulism, E. coli, tetanus, and staph
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
Genome (virus structure)
Genetic material can be RNA or DNA, double or single stranded, linear or circular
Capsid (virus structure)
Protein coat surrounding virus. Removed once inside host cell
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
Latent virus
Enters state of dormancy and doesn’t reproduce (herpes virus)
Viral diseases
Common cold, hepatitis, influenza, and west Nile
Eukaryotic pathogens
Single celled protozoans. Spread by water or food contaminated with animal feces
Eukaryotic diseases
Giardiasis, malaria, schistosomiasis, tape worm, athletes foot/jock itch
Prions
Normal occurring protein produced by brain cells
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
Direct contact
Touching infected organism
Indirect contact
Contacting contaminated object
Vector borne
Transmission through vector
Vector
Organisms that carry disease causing microorganisms from one host to another
Inhalation
Pathogens breathed in from air
Ingestion
Eating contaminated foods
First line of defense
Skin and mucous membranes. Nonspecific defense
Nonspecific defenses
Don’t distinguish one pathogen to another
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)
Mucous membranes
1st line. Line resp, dig, ur, and repro tracts. Secrete mucus that traps pathogens and can be sneezed or excreted away
Second line defense
WBCs, inflammation, defense proteins, and fever. Nonspecific
White blood cells
2nd line. Phagocytes that engulf and digest invaders indiscriminately.
Macrophages
Natural killer cells
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
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
Inflammation
2nd line. Reaction that produces redness, warmth, swelling, and pain. Damages cells release chems that stimulate histamines
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.
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
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
Fever
2nd line. Temp above 97-99F. Macrophages release chem pyrogens as weapons
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.
Third line of defense
Lymphocytes. Specific defense
Specific defense
Attack specific microorganisms
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
Antigens
Foreign molecules that stimulate immune response. Triggers enhanced production of B and T cells
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.
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
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)
Antibodies
Found in lymph, intestines, tissue fluids, and breast milk
Passive immunity
Antibodies passed through breast milk from mother to child. Lasts only as long as the antibodies live in blood
Active immunity
Production if antibodies to combat infection for lifetime after antigen exposure
Allergy
Immune response without presence of a pathogen
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
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
Autoimmune disease
When self testing fails and lymphocytes have antigen receptors for body’s proteins. Causes immune system to attack healthy cells
Multiple sclerosis
T cells specific for protein in nerve cells attack brain
Insulin dependant diabetes
T and B cells attack cells that produce hormone in pancreas
Humoral immunity
Use of memory cells, clinal populations, antibody-antigen complexes, complement proteins, and agglutination. Makes vaccinations possible
Memory cell
Exact copy with same antibodies of B cell made after binding to antigen.
Clonal population
Lots if memory cells that aid in overcoming the infection. Some remain and recognize antigen in future.
Antibody-antigen complex
When antibody binds to antigen. Marks pathogen for phagocytes and degradation by complete proteins causing lysis of foreign cells
Compliment proteins
Circulate body inactive until they bind to surface of microorganisms and become active
Agglutinate
When pathogens and attached antibodies clump together making them unable to infect other cells.
Vaccination
Injections of components of disease causing organisms. Creates clonal population for specific pathogen that will be prepare for a real infection
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
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
Helper T Cells
Also called T4 cells. Boosters. Detect invaders and alert b and T cells that infection is occurring. Secrete interleukin 2
Interleukin 2
Increases level of cytotoxic T cell response
AIDS
Caused by HIV. HIV kills or disables helper T cells and causes deficient immune response . Patients often become ill from opportunistic infections
Opportunistic infections
Only occur when opportunity arises die to weakened immune response
No immune response to prions
Because they are refolded versions of the normal protein. Body still recognizes as self.
Preventing misfolded prions and spongiform encephalopathy
Can’t feed meat and bone meal. No John risk materials used in food or cosmetic products
