Chap 9: infectious disease (1) Flashcards
What are the 6 links in the chain of infection?
- infectious agents
- reservoirs
- portals of exit
- modes of transmission
- portals of entry
- A susceptible host.
(IRa Pulled and Pulled the MOp on the Stairs)
Differentiate between bacteria and viruses.
Viruses are tough, tiny pathogens
-Smaller than bacteria or fungi
-Unable to reproduce on their own, so they must invade a living cell to reproduce
-The infected cell dies, but before it dies it releases new viruses that enter other cells
- Do not always kill the cells they infect, but alter the cell’s function
Bacteria are simple, one-celled organisms
- Complex compared to viruses because they can make copies of themselves (DNA) and contain ribosomes so they can reproduce
- Some have flagella so they can move
- Most plentiful microorganisms and most pathogenic
- Most don’t cause disease but can cause problems
What are the 3 infectious agents?
Fungi, protozoa and helminthes
What are the features of fungi?
Fungi are eukaryotic organisms that come in many shapes and sizes
- Can be single-celled or long chains of cells
- Can spread by reproductive spores or by growing threadlike fibres
- Absorb nutrients from organic material, which may include human tissue
Can be helpful (e.g., make antibiotics)
Which infectious agent can be helpful in making antibiotics?
Fungi
What are the features of protozoa?
Protozoa are single-celled, microscopic organisms
- Release enzymes and toxins that destroy cells or interfere with their function
- Not a major health problem in Canada because of public health measures
Treatment consists of general medical care to relieve the symptoms, replacement of lost blood or fluids, and drugs that kill the specific protozoan
Which infectious agent is not a major concern in Canada because of public measures? and what is the treatment for these diseases?
Protozoa
Treatment consists of general medical care to relieve the symptoms, replacement of lost blood or fluids, and drugs that kill the specific protozoan
What are the features of helminths?What disease is cause by them and how does one contract an infection?
Helminths are small parasitic worms that attack specific tissues or organs and compete with the host for nutrients
- Schistosomiasis is caused by a parasitic worm that burrows through the skin and enters the circulatory system
- Infection can also occur from eating undercooked beef, pork, or fish containing larval forms of tapeworm
How do you develop an infection of helminths?
Infection can also occur from eating undercooked beef, pork, or fish containing larval forms of tapeworm
What are the 5 modes of transmission of infection?
- Direct contact: body surface to body surface
- Indirect contact: contact of a susceptible host with hands or objects that are contaminated
- Droplet contact: spread by nasal, oral, or conjunctival mucosa that comes into contact with large droplets containing germs from another infected person close by (sneeze, cough)
- Airborne transmission: droplets containing germs that are suspended in the air or dust
- Common vehicle transmission: contact with contaminated food, water, or medications
DID Drops of Acid become Common
What is the process of infection?
Incubation period: time between invasion and the first symptom
Prodromal period: as infected cells die, they release chemicals that help block the invasion
Highly contagious
Recovery: begins when body’s forces gain the advantage
In PeRu there is Rain
Explain the immune response in our body
Antigen enters the body, T cells engage in combat with the invader
B cells produce antibodies to assist in the battle
Natural killer cells seek out and destroy viruses and cancer cells
Define lymph nodes
Lymph nodes: area where protective tissues are stored
Define inflammation
Inflammation: redness, swelling, local warmth, and pain
Explain the human lymphatic system and its functions
Tonsils
* Defense against bacteria and other foreign agents
Right lymphatic duct
* Drains right upper portion of body
Thymus gland
* Site where certain white blood cells acquire means to chemically recognize specific foreign invaders
Lymph nodes
* Store protective cells
and destroy pathogens
Bone marrow
* Marrow in some bones serves as production site for infection-fighting blood S cells (as well as red blood cells and platelets)
