Animal Physiology Flashcards
What is the function of the immune system?
capacity to distinguish between body cells (‘self’) and foreign materials (‘non-self’). react to the presence of foreign materials with an immune response eliminating materials from the body.
What are MHC class I molecules and what is their function?
nucleated cells of the body possess unique and distinctive surface molecules that identify it as self. These self markers are called major histocompatibility complex molecules (MHC class I) and function as identification tags. Immune system wont react to them
What is an antigen and how are they recognised by lymphocytes?
A foreign substance triggers an immune response called an antigen. Antigens are recognised by lymphocytes which bind to and detect the characteristic shape of an exposed portion (epitope)
What are antigenic determinants and what are some examples?
specific sites on an antigen that are recognised by the immune system.
- surface markers - foreign bodies in the blood and tissue
- self-markers of cells
- proteins from food - rejected unless they are first broken down into component parts by the digestive system
What is the significance of self markers in the immune system?
Self markers prevent immune rejection of tissue from an individual’s own organism but limit transplant compatibility between different organisms.
Do red blood cells possess the same self markers as other nucleated cells?
Red blood cells are not nucleated and hence do not possess the same distinctive and unique self markers as other body cells.
What is the ABO blood system?
The ABO blood system is a classification system based on the presence of A and B antigens on the surface of red blood cells.
What are A and B antigens?
A and B antigens are surface glycoproteins present on red blood cells, either independently or in combination.
What does it mean if a person has type O blood?
If a person has type O blood, they possess neither A nor B antigens on their red blood cells
What is the significance of the Rhesus factor in blood transfusions?
The Rhesus factor is a glycoprotein present or absent on red blood cells that affects blood transfusion compatibility.
-Pathogens
- cause disease (disturbs the normal functioning of the body)
- generally species-specific in that their capacity to cause disease (pathogenesis) is limited to a particular species
zoonotic diseases
Diseases from animals that can be transmitted to humans
Disease Transmission
- Direct Contact - physical association
- Contamination - ingestion
- Airborne - air via coughing and sneezing
- Vectors - intermediary organisms that transfer without developing disease symptoms themselves
Non Specific VS Specific immune reaction
Non Specific - macrophages will engulf pathogens non-selectively and break them down internally
Specific - dendritic cells present antigens to lymphocytes. B and T lymphocytes recognize a specific antigen
Specific Immune response
- TH cells are activated by antigenic fragments presented by dendritic cells and release cytokines that stimulate specific B cells.
- Clonal selection occurs, resulting in the production of short-lived plasma cells and long-lived memory cells.
- Pathogens contain multiple distinct antigenic fragments that stimulate a variety of specific antibodies.
Specific B Lymphocytes
Activated then divides into plasma and memory cells. Plasma cells - Secretes high numbers of antibodies
Antibody function
- Precipitation – Soluble pathogens become insoluble and precipitate
- Agglutination – Cellular pathogens become clumped for easier removal
- Neutralisation – Antibodies may occlude pathogenic regions
- Inflammation – Antibodies may trigger an inflammatory response within the body
- Complement activation – Complement proteins perforate membranes
Clonal Expansion
An adaptive immune system is when plasma cells produce a lot of antibodies.
- Delay between initial exposure to a pathogen and the production of large quantities of antibodies. pathogens can reproduce rapidly during this delay period, they can impede normal body functioning and cause disease
what is produced to prevent delay during clonal expansion
Memory Cells
How do memory cells work
- B cell is activated which forms memory cells and some differentiate to form memory cells
- They live for a long time and produce low levels of antibodies that are constantly circulating
- So therefor when a pathogen re-enters the system the memory cells act more vigorously to produce more antibodies
- As the antibody is produced faster the pathogen cannot reproduce enough
Allergen
An environmental substance that triggers an immune response despite not being directly harmful
- severe allergic reaction is called anaphylaxis (can be fatal)
How an allergic reaction happens
- Specific B cell encounters the allergen it creates plasma cells hence antibodies (lgE)
- These specific lgE antibodies attach to mast cells which will prime them towards the allergen
- Once reexposed the lgE-primed mast cell will release a large amount of histamine causing inflammation
What can inflammation improve
Leukocyte mobility to infect regions by triggering vasodilation and permeability
Vasodilation - cause redness and heat as it increases circulation
Permeability - cause swelling more fluids leak from blood
Vaccination
The weakened pathogen is injected into blood stream unable to cause harm. This allows the body to detect it and create memory cells. Which will help to improve delay time.
Herd immunity
Individuals who are not immune to a pathogen are protected from exposure by the large amounts of immune individuals within the community
monoclonal antibodies
artificially derived from a single B cell clone (identical specific antibodies)