Lecture 20: Intro to blood and immune Flashcards
What are the components of blood?
Plasma - water and dissolved substances
White blood cells
Platelets
Red blood cells
What is the function of red blood cells?
Carry oxygen in blood
What is the function of white blood cells?
Involved in immune response
What is the function of platelets?
Blood clotting
What are neutrophils?
White blood cells that engulf pathogens - phagocytosis
What are lymphocytes?
B and T cells - they have a range of functions e.g. carry receptors to sense pathogens
What are monocytes?
Precursor to macrophages (phagocytes)
Scavenge and sense pathogens
What are the two functions of immune system?
Differentiate between self and non-self antigens
Seek and destroy non-self antigens
Define pathology
Study of diseases and how they progress
Define pathogen
Something that causes a disease, for example bacteria or virus
Define immune system
A system of defenses to stop invading pathogens
Define immunogenic
Something which induces an immune response in the body
Define antigen
A molecule which induces an immune response via a lymphocyte - pathogens show antigens on their surface
Define antibody
A molecular component of the immune system that recognises and binds with antigens
What is innate immunity?
The defense systems that are always deployed
What are the 3 lines of defense? Classify innate and adaptive immunity
First line of defense (innate)
- skin
- secretions
- mucous membranes
Second line of defense (innate)
- phagocytic cells
- natural killer cells
- defensive proteins
- inflammatory response
Third line of defense (adaptive)
- adaptive defenses
- lymphocytes (B and T cells)
- antibodies
Which body system is part of the immune system and at which stage does it function?
The lymphatic system is involved in both the second and third line of defense - involved in innate and adaptive immunity
How do pathogens enter the body?
Eat, breathe, touch - hence blocked by external defenses first
What are external innate defenses?
Bodies first line of defense to invading pathogens
- skin
- secretions
- mucous membranes
What are internal innate defenses?
Second line of defense
- phagocytic cells
- natural killer cells
- defensive proteins
- inflammatory response
How does the inflammatory response occur?
Histamine is released from injury site
The blood vessel dilates and its permeability increases
This allows blood cells to leave the blood vessels and enter injury site causing redness and swelling
Cells carry out phagocytosis
Virus-infected and cancer cells are killed
How does phagocytosis occur?
Phagocytes have receptors that detect pathogens
A phagosome is formed as the bacteria is engulfed
Phagosome binds with lysosomes to form phagolysosomes
Bacteria broken down and soluble debris leaves
What is the internal adaptive defenses?
Third line of defense:
B lymphocytes and T lymphocytes
Antibodies
Where are B cells produced and what is its function?
Develop and specialise in the bone marrow
They make antibodies
Where are T cells produced?
Develop in bone marrow and mature in the thymus
How are B and T cells activated?
Specific shapes of receptors detect specific pathogens
What are the characteristics of antigens?
- Immunogenicity - ability to provoke an immune response by stimulating production of antibodies or T cells
- Reactivity - ability of antigen to react specifically with antibodies or cells it provoked
What happens on second exposure to a pathogen?
There would be memory B and T cells in the lymph nodes
These are activated if the body is exposed a second time to the same pathogen
The secondary response is much faster, stronger and lasts longer than the first
(this is how vaccines work)
What is serology?
Study involving determination of whether an infection is acute or historical
What is a serosurvey?
Collection and blood testing of blood from a defined population to estimate the prevalence of antibodies against an infectious pathogen as an indicator of exposure
