9 SCI Immune System

What are plagues?

Continuous diseases that spread rapidly through a population with high death rates.

What are pandemics?

Worldwide diseases.

What does herd immunity do?

Limits the spread of disease and protects vulnerable individuals. Allows protection of those unable to be vaccinated. More vaccinated = lower chance of infection.

What does vaccination do?

Trains immune system to fight pathogens without being put into danger. It generates antibodies and forms memory of pathogens.

What is active immunity?

When memory cells are formed and specific antibodies bind to antigens.

What is artificial immunity?

When a disease is replicated by injecting toxoids (safe toxins) so the body is able to produce antibodies faster.

Some diseases jump to humans from...

Animals. Eg bird flu and swine flu.

What are epidemics?

Diseases in one country/region that happen in a relatively short time.

What is herd immunity?

The protection that exists when a high proportion of the population is immunised against a disease.

What is passive immunity?

When no memory cells are formed, and body reacts as it did the first time.

How is immunity received?

Vaccination or previous exposure to the disease. On the second exposure to the antigen, the immune system produces more antibodies faster.

What is immunity?

Resistance to a particular disease causing pathogen. Immune people don't develop the disease.

What do memory cells do?

Remember diseases so next time you're infected you heal faster and sometimes don't even get symptoms.

What do lymphocytes form?

Memory cells.

What do regulatory T cells do?

Stop attacks after virus is killed.

What do cytotoxic T cells do?

Produce toxic agents to kill targets.

What are the 3 things that helper T cells do?

Notify killer T cells that a cell is infected. Stimulate B cells to make antibodies. Stimulate T cells to become active.

What happens when T cells are activated?

They secrete cytokines to directly attack infected or cancerous cells and stimulate the growth of more T cells.

What are the 4 types of T cells?

Helper T cells, Killer T cells, Cytotoxic T cells and Regulatory T cells.

Why do T lymphocytes kill self cells?

When self cells are infected, because by killing the cell it kills the cause of infection and reduces the risk of spreading.

What cells do T lymphocytes attack?

Not only foreign invading cells, but also may attack self cells that have been invaded by a virus etc.

What cells do B lymphocytes attack?

They can only attack non-self cells.

What do antibodies do?

Bind to invaders antigens to disable them, and clump them together ready for phagocytosis.

What do plasma cells do?

Produce chemicals called antibodies that are specific to the invaders antigen.

What do B lymphocytes do?

Divide into plasma cells.

Where do B and T blood cells originate?

Bone marrow.

What are B and T white blood cells?

Lymphocytes.

What does the lymphatic system consist of?

Lymph vessels, lymph nodes, lymph and white blood cells.

What does the lymphatic system do?

Manages fluids in the body, filters out bacteria and houses types of white blood cells.

What are phagocytes?

Special types of white blood cells that engulf and destroy pathogens and other foreign material.

Where does histamine come from in 2nd line of defence?

Damaged skin dermis releases histamine.

Why does blood flow increase in 2nd line of defence?

Histamine released causes blood and white blood cells to flow to the site of infection.

What happens when the 2nd line of defence is activated?

White blood cells rush to area, making it red and inflamed, sometimes even swollen.

What is the 2nd line of defence?

A selection of immune cells and proteins that non-specifically attack non-self cells.

Chemical barriers include...

Body fluids, stomach acid, saliva and tears.

Physical barriers include...

Intact skin, cilia and nasal hairs.

What is the first line of defence?

A non-specific group of physical and chemical barriers to prevent the entry of invading pathogens.

What happens when antigens are non-self?

They trigger an immune response.

What are antigens?

Proteins that stay on the surface of cells that allow our body to recognise cells as self or non-self. All antigens are unique.

What is the spiral bacterium called?

Spirochaete.

What is a rod shaped bacterium called?

Bacillus.

What is the spherical bacterium called?

Coccus.

What type of parasite is a virus?

Obligate intracellular parasite.

How do we prevent the spread of disease?

Quarantine laws, personal/animal hygiene, clean water, vaccination, sanitisation, food safety and treatment.

What gets rid of contaminated water?

Lots of pathogens live in water, but are often killed or filtered out. When this doesn't happen the water is contaminated.

Contaminated objects...

transmit diseases when non-infected people touch a surface touched by an infected person.

What do viruses contain?

Genetic material in the form of DNA or RNA, packaged in a protective protein coat, known as a capsid.

Are viruses cellular or non-cellular pathogens?

Non-cellular pathogens.

Are prions cellular or non-cellular pathogens?

Non-cellular pathogens.

A parisite is...

something that gains benefits while harming it's host.

What effects the microbiome?

Antibiotics, the environment and diet.

The microbiome is...

An assortment of good and bad bacteria that live all over the body, but are mainly in the gut.

What type of organism is a protozoa?

A microorganism.

Cellular pathogens are...

Pathogens made of cells. Eg: Animals, fungi, protozoa and bacteria.

Non-cellular pathogens are...

Pathogens not made of cells. Eg: viruses and prions.

What are the modes of transportation?

Direct contact, air-born droplets, vectors, contaminated objects and water supply.

Vectors are...

Organisms that carry disease causing pathogens between other organisms, without being effected by the disease themself.

What are infectious diseases?

Contagious diseases caused by a pathogen.

What are non-infectious diseases?

Diseases that can't be spread from one place to another, and is not contagious.

Examples of non-infectious diseases?

Obesities, diabetes and depression.

Diseases definition?

Any change that impaires the function of an individual in some way. It causes harm to the individuals.

What are prions?

Abnormal/infectious proteins that convert normal protein into prion protein.

What is the intermediate/secondary host?

The host used for larval stage.

What is the primary host?

The organism used for adult stage.

Pathogen parasites are...

Parasites that harm and cause hosts to become diseased are considered pathogens.

Ectoparasites live...

Outside the body of the host.

Endoparasites must...

Live inside the body of the host.

Pathogens are...

Disease carrying organisms - the cause of all infectious diseases.

What do pathogens do?

Cause damage to host.

Are viruses pathogens?

Yes, they damage host cells.

What parasite has to infect it's host before reproducing?

Obligate intracellular parasites.

Coronavirus gets it's name from...

Corona, or crown of spikes gets it's name from it's characteristic shape. Spikes bind to receptors of host cell. Has strand of RNA.

How often do bacteria reproduce?

Every 20 minutes, the more bacteria, the more unique.

How is the influenza virus always evolving?

It gets new surface proteins humans have little immunity to, generally because it comes from an animal strain.

The influenza virus is constantly...

Evolving. Pandemics happen every few decades.