Immune system Flashcards
What is an antibody?
A protein that can identify and fight a specific pathogen
Antibodies are produced by B cells and are specialized to fight one type of pathogen.
What is a B cell
A white blood cell that produces proteins to attack pathogens
When a B cell finds a matching pathogen, it clones itself and produces antibodies to fight the infection.
What is a bacterium
(plural: bacteria)
A simple, single-celled microbe without a nucleus
E. coli is a type of bacteria that causes disease by attaching to cells and releasing toxins.
Whatis a chemical barrier?
A defence that kills pathogens before they can enter the body
**Stomach acid **and the enzymes in saliva and tears are examples of chemical barriers.
What are Cilia ?
**Microscopic hairs on cells **that line the airways
Cilia push out mucus and trapped pathogens from the airways and lungs.
What is a contagious diesase?
A medical condition that can** spread from person to person** by a pathogen
Measles is highly contagious because one person can spread it to as many as 18 other people.
What is a disease?
A medical condition with specific symptoms
Diseases** may be infectious**, such as chickenpox, or non-infectious, such as cancer.
What is a fever?
An increase in core body temperature over an extended time
A fever **helps fight an infection **by slowing or killing pathogens.
What is the Body’s first line of defence?
Barriers that prevent pathogens from entering the body
**Skin, saliva, urine and tears **are barriers in the first line of defence.
What is Fungus (plural Fungi)
An organism with complex cells that feeds off a living host
Some fungi can feed off dead skin between the toes, causing athlete’s foot.
What is Herd immunity
The protection from infection provided when most of a population is immune
Herd immunity protects vulnerable and unvaccinated people because they are less likely to be exposed to infection.
What is the immune system?
The body system that prevents and fights disease
The immune system includes** the skin, fever and specialized white blood cells.**
What is immunity?
The body’s ability to** protect **itself from infection
The body can build up immunity to pathogens by fighting off an infection or by being vaccinated.
What is an infection?
An invasion of the body by pathogens that then multiply
Pathogens can infect the body through the mouth, eyes, lungs, genitals and open wounds.
What is infection rate?
The percentage of unvaccinated people who become infected with a disease
A high infection rate occurs when the vaccination rate is very low.
What is an infectious disease?
A medical condition that is caused by a pathogen
Chickenpox and the flu are examples of infectious diseases.
What is inflammation?
A painful redness or swelling of part of the body
Inflammation occurs when increased blood flow brings white blood cells to fight invading pathogens.
What is a memory cell?
A B cell that **remains **in the bloodstream to recognize pathogens
Memory cells** provide long-term immunity** by responding to infections faster and stronger than before.
What is a microbe?
An **organism that is too small to be seen **with the naked eye
Microbes include bacteria and some types of fungi.
What is mucus?
A sticky liquid that** lines the nose, throat, lungs and intestines**
Snot is the mucus produced by a special membrane in the nose.
What is a negative feedback loop?
A change in a system causes another change in the opposite direction
During a fever, negative feedback loops work to keep body temperature within narrow limits.
What is a** non contagious disease?**
**A medical condition that cannot spread from person to person
The yellow fever virus passes from mosquitoes to people but cannot spread from person to person.
What is a non infectious disease?
**A medical condition that is not caused by a pathogen
**Diabetes, asthma **and cancer are examples of non-infectious diseases.
What is a pathogen?
A microscopic organism or agent that causes disease
Pathogens include E. coli bacteria and the measles virus.
What is a phagocyte?
A white blood cell that engulfs and destroys pathogens
Phagocytes help fight infections by engulfing and breaking down viruses and bacteria.
what is a physical barrier? (first line of defence)
A defence that blocks or traps pathogens before they can enter the body
Skin, mucus and cilia are examples of physical barriers.
What is the bodies second line of defence?
General responses to pathogens inside the body
The second line of defence includes fever, inflammation and phagocytes.
what is the bodies third line of defence?
Responses to specific pathogens inside the body that build immunity
The third line of defence includes B cells, memory cells and antibodies.
What is vaccination?
A treatment that helps build immunity to an infectious disease
Most vaccinations are given by injection but some are given by mouth or as a nasal spray.
What is vaccination rate?
The percentage of a population that is vaccinated against a disease
A high vaccination rate can provide herd immunity by preventing a disease from spreading to vulnerable people.
What is a vaccine?
A substance that boosts the body’s immunity to a specific pathogen
Vaccines can be made from dead or weakened pathogens and cause the body to make new antibodies.
What is a virus?
A microscopic infectious agent made of genetic material and proteins
Chickenpox is caused by a virus that reproduces inside cells and can spread from skin sores.
What is a white blood cell?
A component of blood that fights infections
Phagocytes, B cells and memory cells are types of specialized white blood cells.
