immune system Flashcards
(18 cards)
what is immunology?
Study of physiological mechanisms which enable the body to recognise material as foreign and to neutralise, eliminate or metabolise them without injury to the host
what is the immune system
- a system that fights disease-causing germs (Pathogens) and removes them from the body
- Recognises and neutralise harmful substances form the environment
- Fights disease-causing changes in the body, such as cancer cells
organs of the immune system
Lymph nodes
Appendix
Bone marrow
Tonsils and adenoids
Thymus
Spleen
Payer’s patch
what are the three lines of defence in the immune system
- Physical and chemical barrier
- Non-specific innate responses
- Specific adaptive responses (acquired immunity)
the immune system
what is a pathogen and antigen?
Pathogen: an agent that causes or generates disease
- Micro organisms
- Parasites
- Foreign particles/substances:
Antigen: a substance that has the ability to provoke an immune response
- Foreign molecules
- Nonself/intruders
what is the thymus
- Consists of two lobes located in the thoracic cavity and neck
- The site of T-cell maturation and specialization
- Vital for bodys defense against pathogens
what are tonsils
- Organs in pharynx
- Filled with macrophages, B/T lymphocytes
- Respond to infectious agents that arrive via food ingestion or inspired air
what is peyers patch?
Aggregated lymphoid follicles in small intestine and appendix
what is innate immunity
The first and second line of defence
Nonspecific protection against foreign material cells
Relies on physical barriers and phagocytic cells to remove lower organisms and natural killers for viruses
what is the first line of defence
- The protective barriers of the body
- It prevents the entry cells and molecules into the body.
barriers such as: - skin
- mucous membrane
- chemcial and environmetnal barriers
second line of defence
Come into effect when 1st line of defences breached
Includes:
- Inflammation
- Antimicrobial proteins
- Phagocytes
- Natural killer (NK) cells
- Fever
characteristic features of the second line
Acute inflammation begins within seconds to minutes following injury to tissues.
- Redness: due to vasodilatation and increased blood flow
- Heat: due to increased blood flow
- swelling due to increased vascular permeability
- pain: due to stimulation of the local nerve endings, from mechanical and chemical mediators
what is an antigen
a substance that has the ability to provoke an immune response
what is an antibody
protective protein produced in response to antigens
B cells produce antibodies.
what is the third line of defence
is the acquired immunity that is composed of humoral and cell mediated immunity
what is aquired immunity?
When specific cells of the immune system recognise and respond to antigen
Effectiveness of response towards an antigen increases following re-exposure to the samae antigen
Acquired immunity is divided into humoral and cell-mediated immunity
what is humoral immunity
involves the production of antibodies by B lymphocytes (B cells) to fight pathogens found outside of cells (extra cellular pathogens)
what is cell mediated immunity
T lymphocytes react to pathogens that live and multiply inside of cell to host (intreacellular pathogens)
