MGY277H1 Study Guide - Final Guide: Measles, Haptoglobin, Mucosa-Associated Lymphoid Tissue
8 Jun 2018
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Friday, April 10, 2015
UNIT 10
Overview:
1. Overview of innate defences
2. First line of defences
3. Cells of the immune system
4. Cell communication
-Intro to the Immune System:
-Innate immunity: Protects against microbes that an individual is seeing for the first
time.
-Skin and mucous prevents entry, nutrient restriction prevents growth of bacteria,
sensor systems detect invaders and induce a response based on MAMPs
-Adaptive immunity: Develops throughout life and is initiated by innate immunity.
-Foreign Ags are recognized and a response is generated based upon development of
Abs and immune cells specific for that molecular target. This response allows the
immune system to deal with that specific pathogen, often by targeting them for killing.
-This generally elicits immune memory so that the individual can respond quicker if the
same Ag is encountered.
-First-line defences are barriers that separated and shield the interior of our bodies
from the surrounding env.These are the barriers microbes must overcome to enter
and invade our tissues. The first-line of defence is the skin and mucous membranes
and they remain job is to prevent bacterial entry.
-Innate defences recognize and destroy invaders who enter the first line by using
pathogen-recognition receptors yay detect and send warning signals or by using the
complement system that will remove and destroy invaders (and also works with
adaptive immunity.
-Once an invader or any tissue damage is detected, an inflammatory response is
initiated. This is seen when local blood vessels undergo changes and when
phagocytes leave bloodstream and accumulate in tissues. This is the end outcome to
all responses generated against the pathogen.
-Body borders: serves as first-line defences against invading microbes. Some borders
are thought to be “inside” the body but they are in contact with external env.
Examples include: Digestive tract and Respiratory tract.
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Friday, April 10, 2015
-This image shows the body borders we see in some of the internal tracts in our body.
-1. Skin: Physical Barriers
-It makes it difficult for microbes to penetrate as the cells in the skin are tightly packed.
The dermis contains tightly woven fibrous CT and the epidermis has many layers of
epithelial cells. These cells are dead and filled with keratin, they repel water allowing
for a dry env and they continually slough off along with any attached microbes.
-2. Mucous membranes: Physical Barries
-These membranes line the digestive, rep and genitourinary tracts. These membranes
are constantly bathed in secretions that will wash microbes away.
-Microbes are moved down by a constant motion called peristalsis, this is seen in the
digestive tract. Mucociliary escalator in the resp tract allows for movement of
microbes.
-Antimicrobials: are substances that protect skin and mucous membranes.
Examples are:
-1. Salt: from perspiration on skin - however salt-tolerant organisms will be
susceptible.
-2. Lysozyme: degrades peptidoglycan - it is seen in tears, saliva, mucus, phagocytic
cells and blood.
-3. Peroxidase: enzymes break down hydrogen peroxide - reactive to O2 however
catalase-negative are susceptible.
-4. Defensins: form pores in microbial membranes - examples are peptides produced
by neutrophils and epithelial cells.
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Friday, April 10, 2015
-5. Complement: proteins mark cells for direct or indirect killing - these complement
cascades are present in blood and mucosal secretions.
-6. Acidic stomach, vagina and tears make life inhospitable for most microbes.
-Nutritional Immunity:
-1. Transferrin: Transports iron from stores in the liver to cells that require it for growth.
It quickly binds free iron to make it unavailable to microbes.
-2. Lactoferrin: Released at sites of infection to further deplete iron.
-3. Haptoglobin: Bind free hemoglobin released from lysed RBCs
-4. Albumen and Calprotein: bind free zinc to make it unavailable.
-Microbial Helpers:
-1. Commensal microbia: represent microorganisms that grow on body surfaces of a
healthy individual. They are NOT part of the immune system but they do provide
protection. They are important for developing the immune system to be able to
distinguish harmless microbes from pathogen.
-They provide protection by: Competitive exclusion and produce toxic compounds.
-Disruption of normal microbiota can predispose a person to infections. This could
happen due to antibiotic use.
-Certain diseases can be suppressed due to restoration of normal flora eg
inflammatory bowel disease.
-CELLS OF THE IMMUNE SYSTEM:
-formation, development termed hematopoisis
- BCs originate from
hematopoietic stem cells
that is found in bone
marrow and indicted by
colony-stimulating factors
(CSFs)
- These cells will move
around the body to make
sure everything is normal.
The numbers will increase
during an infection.
- There are three different
categories of these cells:
RBCs, platlets and WBCs.
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Document Summary
Overview: overview of innate defences, first line of defences, cells of the immune system, cell communication. Innate immunity: protects against microbes that an individual is seeing for the rst time. Skin and mucous prevents entry, nutrient restriction prevents growth of bacteria, sensor systems detect invaders and induce a response based on mamps. Adaptive immunity: develops throughout life and is initiated by innate immunity. Foreign ags are recognized and a response is generated based upon development of. Abs and immune cells speci c for that molecular target. This response allows the immune system to deal with that speci c pathogen, often by targeting them for killing. This generally elicits immune memory so that the individual can respond quicker if the same ag is encountered. First-line defences are barriers that separated and shield the interior of our bodies from the surrounding env. these are the barriers microbes must overcome to enter and invade our tissues.
