Infection And Immunity Flashcards
What is the definition of infection?
A disease state that results from the presence of pathogens (disease-producing microorganisms) in or on the body.
Pathogens can stimulate the immune system into action.
What are antigens?
Molecular markers of cells, viruses, and other particles.
Antigens help the immune system recognize foreign substances.
Define pathogens.
Microorganisms that can cause a disease.
Examples include bacteria, viruses, fungi, and parasites.
What are microorganisms?
Microorganisms include bacteria, protozoa, and fungi.
They are typically too small to be seen without a microscope.
What is an organism?
A living thing made up of one or more cells.
Organisms can be unicellular or multicellular.
What is a virus?
A small particle consisting of nucleic acids and a protein coat.
Viruses require a host cell to reproduce.
Define bacteria.
Tiny, single-celled organisms of various shapes.
Bacteria can be beneficial or pathogenic.
What are fungi?
Also called mycosis, is a skin disease caused by a fungus.
Fungi can cause infections in humans and animals.
Define a parasite.
An organism living in, on, or with another organism to obtain nutrients.
Parasites can cause various diseases.
What is virulence?
The ability to cause a disease.
Factors influencing virulence include the pathogen’s ability to invade host tissues.
What does acute mean in medical terms?
Rapid development and short duration of a disease.
Acute diseases often appear suddenly and may resolve quickly.
Define chronic.
Develops slowly and lasts for longer periods of time, possibly for life.
Chronic diseases can be managed but not always cured.
What does idiopathic mean?
Unknown or undetermined cause.
Idiopathic conditions can be challenging to diagnose and treat.
What is an infectious disease?
Any type of disease caused by pathogens.
Infectious diseases can be caused by bacteria, viruses, fungi, or parasites.
What does contagious mean?
A disease that can spread from person to person.
Not all infectious diseases are contagious, but all contagious diseases are infectious.
What are the two types of organisms that cause infection?
Virus and non-viral organisms.
Non-viral organisms can live independently of other cells.
What are characteristics of viruses?
Can reproduce but have no organelles or membrane, and need to take over host cells to reproduce.
Viruses only survive for a short time outside of a host cell.
What are non-viral organisms?
Have a cell membrane, cytoplasm, DNA, RNA, but some do not have a nucleus.
They are capable of living independently of other cells.
What is a virus?
Tiny microorganisms that cannot live long outside the host’s cell.
How do viruses reproduce?
They take over the host’s cells to reproduce and metabolize.
What happens when a virus invades a host cell?
It inserts its genetic makeup into the cell, replicating itself.
What occurs after a virus replicates inside a host cell?
The host cell dies, releasing virus cells that go on to infect other host cells.
What is the effect of some viruses on infected cells?
They stimulate the infected cell to replicate very fast, which can result in a tumor.
List examples of diseases caused by viruses.
- Chicken pox
- Measles
- Hepatitis
- Influenza
- COVID-19
