Microbiology Flashcards
What is a disease
A disease is a state in which there is a structural or functional abnormality of the body causing a disturbance of normal health.
What process in the body brings about significant changes but is not a disease?
Pregnancy
what are the causes of disease
Genetics
Autoimmune diseases
Tumors and cancer
Inflammation
Malnutrition and obesity
Pathogens
Physical and Chemical agents
what are pathogens
are disease-producing microbes including bacteria, viruses,fungi,protozoa
what are parasites
are multi-cellular worms and are often clearly visible to the naked eye such as tapeworms
what is a bacterium
A bacterium is a tiny, primitive cell without a nucleus some bacteria live harmlessly in the body making up normal flora
what is commensals
which and receive shelter and benefit the host by keeping potentially harmful microbes at bay.if they migrate to a different anatomical location, they can cause infection
what is pathogenic bacteria
this is where Bacteria are able to cause a disease
what is Virulence
This is the extent to which they CAN cause a disease.refers to the degree of pathogenicity or the ability of a microorganism to cause disease in a host organism.
What is opportunistic bacteria
They cause infection only in people whose immune status is compromised by illness, drugs or the invasive procedures they have undergone (e.g. surgery, endotracheal intubation, IV access).
They do not attack healthy tissues
what are the three Classification of Bacteria
Shape
Staining
Function
what are the three basic bacteria shapes
Bacilus - roldlike
Coccus - spherical
Vibrio spirillum, or spirochete - curved
What are the Classification by Shape: Bacilli
Bacillus
Diplobacillus
Streptobacillus
what are the classification by shape Cocci
Cocci are round bacteria.
Monococcus
Diplococcus
what is the Classification by Shape: Staphylococci
Clusters of cocci are termed staphylococci
What is the classification by shape Streptococci
Streptococci are round bacteria found in chains
What is the classification by shape Vibrios
Vibrio are curved rods
What is the classification by shape Spirochettes
Spirochaetes are very small, flexible spirally shaped bacteria
Classification by Staining properties gram negative
Gram negative bacteria cannot retain the crystal violet stain, instead taking up the counter-stain and appear red or pink.
What is the classification by function aerobic
Aerobic bacteria need oxygen for their metabolism.
What is the classification by function anaerobic
Anaerobic bacteria metabolise in the absence of oxygen
What is the process of bacterial infections
Secrete toxic substances that damage human tissues
Become parasites inside human cells
Form colonies in the body that disrupt the cell and ultimately disrupt normal human function.
what are the stages of infection
- Gain access to the host tissue
- Move to a favourable site
- Multiply successfully in spite of the host defence mechanisms
- Reproduce so new pathogens can be disseminated
What are the portals of entry
Inhalation
Ingestion
skin and mucous membranes
vertical transmission
urogenital tract
What is inhalation
The respiratory tract serves as the gateway. Airborne particles are released as infectious aerosols—droplet transmission via forceful exhalation, sneezing, or coughing. Longer exposure increases the risk of transmission.
What is skin and mucous membranes
Pathogens inoculated through surgical procedures, injuries, or needles.
What is ingestion
Gastrointestinal tract invasion through contaminated food or water.