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