immunity & disease (1 - 20)
Topics
Phagocytosis
Phagocytosis is a process where cells, particularly immune cells, engulf and destroy foreign
substances or pathogens, such as bacteria and viruses.
It's a crucial component of the immune system.
Macrophages and neutrophils are key cells involved in Phagocytosis.
Phagocytosis involves the formation of a phagosome, which fuses with a lysosome.
Defected phagocytosis can lead to immune system disorders.
Key Terms
Active immunity
Active immunity is the body's natural defense mechanism where it produces its own antibodies
to fight off pathogens.
Active immunity is acquired through vaccination or natural infection.
It provides long-term protection against future exposure to the same pathogen.
It takes time for active immunity to develop, usually a few weeks to months.
Active immunity provides specificity, meaning it targets specific pathogens.
Antigens
Antigens are substances that provoke an immune response, triggering the production of
antibodies to fight against foreign invaders.
Antigens are typically proteins or polysaccharides found on the surface of cells or viruses.
Foreign antigens are recognized as non-self and stimulate the immune system to mount a
defense.
Some antigens are specific to certain pathogens, allowing for targeted immune responses.
Antigen-antibody interactions form the basis of many diagnostic tests, including blood typing
and pregnancy tests.
autoimmune diseases
Autoimmune diseases occur when the body's immune system mistakenly attacks its own healthy
cells and tissues.
Common autoimmune diseases include rheumatoid arthritis, multiple sclerosis, and lupus.
These diseases can affect multiple organs and systems in the body.
Autoimmune diseases are typically chronic and can cause a range of symptoms.
Diagnosis of autoimmune diseases often involves blood tests, imaging studies, and
examination of symptoms and medical history.
Body defense
The body employs various systems to protect against harmful organisms and substances, such
as skin acting as a physical barrier and white blood cells recognizing and attacking foreign
invaders.
Immune system produces antibodies to neutralize pathogens.
Inflammation helps to wall off infections.
Fever can help to slow the growth of pathogens.
Vaccines stimulate the immune system to remember and respond more effectively.
Lymphocytes
Lymphocytes are a type of white blood cell that play a crucial role in the immune system, helping
to defend the body against infections and diseases.
There are three main types of lymphocytes: B cells, T cells, and natural killer cells.
B cells produce antibodies that bind to pathogens, marking them for destruction.
T cells directly attack infected cells or coordinate the immune response.
Natural killer cells kill infected or cancerous cells without prior exposure.
Memory Cells
Memory cells are specialized cells in the immune system that remember previously encountered
pathogens and help mount a faster and stronger immune response upon re-infection.
Memory cells are generated following an initial immune response to a pathogen.
They can live for long periods of time, sometimes even for the entire lifespan of an individual.
There are two main types of memory cells: B memory cells, which produce antibodies, and T
memory cells, which help activate other immune cells.
The presence of memory cells allows for a more rapid and efficient immune response upon
subsequent exposure to the same pathogen.
Passive immunity
Passive immunity is the temporary immunity acquired from an external source, such as receiving
antibodies from another organism.
Passive immunity does not require the immune system to produce its own antibodies.
It provides immediate protection against a specific pathogen.
It can be naturally acquired through the placenta during pregnancy.
It can also be artificially acquired through the administration of immune serum or antitoxins.
Pathogen
A pathogen is a disease-causing agent, such as a virus, bacteria, fungus or parasite, that infects
a host organism and can lead to illness or disease.
Pathogens can spread through direct contact with an infected person, through air droplets, or
through contaminated food or water.
Pathogens can cause a wide range of diseases, from minor infections like the common cold,
to more severe illnesses like pneumonia or malaria.
The body's immune system plays a crucial role in defending against pathogens and
preventing them from causing harm.
To prevent the spread of pathogens, good hygiene practices such as regular handwashing
and proper food handling are important.
Transmissible Disease
Transmissible diseases are illnesses caused by pathogens that can be passed from one
individual to another through various means such as air, water, or direct contact.
Common modes of transmission include respiratory droplets, contaminated food or water,
sexual contact, and vector bites.
Preventative measures like vaccination, good hygiene practices, and quarantine help control
the spread of transmissible diseases.
Major examples include the flu, HIV/AIDS, COVID-19, and malaria.
Understanding the transmission pathways and symptoms of different diseases is crucial for
effective diagnosis and public health management.
Vaccination
Vaccination is a method to stimulate the immune system against a specific disease, by
introducing a weakened or inactivated form of the pathogen.
Vaccination can help prevent the spread of infectious diseases.
Vaccines can be given orally, through injections, or by nasal sprays.
Some vaccines require multiple doses to ensure long-lasting immunity.
Vaccination can cause mild side effects like soreness or fever, but serious reactions are rare.
White blood cells
White blood cells are a crucial part of the immune system, responsible for fighting off infections
and diseases.
They are produced in the bone marrow.
There are several types of white blood cells, including neutrophils, lymphocytes, monocytes,
eosinophils, and basophils.
White blood cells are able to recognize and destroy harmful pathogens.
The levels of white blood cells in the body can indicate certain health conditions and
infections.