Who are the most succeptible to infections?
- Younger children 1-4
- Older adults over 50
What is species resistance?
Correct chemical receptors are not present on human cells for pathogens that affect other species. Also the conditions may be incompatible with those needed for pathogen's survival
What are human pathogenic agents?
Why does the immune system not destroy our body cells?
because when we are young the body develops a tolerance and learns what not to attack and what to attack
What are the 4 classes of pathogens that the immune system protects against?
- 1. Extra cellular bacteria, parasites, fungi
- 2. intracellular bacteria, parasites
- 3. viruses (intracellular)
- 4. Parasitic worms (extracellular)
What are some examples and diseases caused by extracellular bacteria, parasites, and fungi?
- examples: streptococcus pneumoniae, clostridium tetani, trypanosoma brucei, pneumocystis carinii
- Diseases: pneumonia, tetanus, sleeping sickness, pneumocystis pneumonia
What are some examples and diseases of intracellular bacteria and parasites?
- Mycobacterium leprae (leprosy), Leishmania donovani (leishmaniasis)
- Plasmodium falciparum (malaria)
What are some examples of diseases caused by viruses?
- Variola (smallpox)
- Influenza (flu)
- Varicella (chickenpox)
What are diseases caused by parasitic worms?
- Ascaris (ascariasis)
- Shistosoma (Shistosomiasis)
What are the 2 general mechanisms of the immune system?
- 1. Innate immunity (nonspecific mechanisms)
- 2. Adaptive Immunity (specific mechanisms)
What are some of the characteristics of the response of Innate immunity?
- 1. rapid response (hours)
- 2. fixed (always there and protects against all different kinds)
- 3. limited number of specificities
- 4. constant during response
What are examples of innate immunity?
- Skin (keratin protects)
- Mucous membranes
What is an example of adaptive immunity?
What are some characteristics of the adaptive immune response?
- 1. slow response (days to weeks)
- 2. variable (immunity increases with number of exposures) - booster shots
- 3. numerous highly selective specificities
- 4. improve during response (memory)
What are the categories of Innate Immunity?
- 1. first line defenses
- 2. phagocytosis
- 3. inflammation
What is the definition of the body's first line of defense?
Structures, chemicals, and processes that work to prevent pathogens from entering the body (skin and mucous membranes).
How does the epidermis protect from pathogens?
Multiple layers of tightly packed cells defer most pathogens from penetration. Shedding of dead skin cells removes microorganisms. Epidermal dendritic cells phagocytize pathogens.
How does the dermis protect against pathogens?
Collagen fibers help skin resist abrasions that could introduce microorganisms.
What are some other defenses of the skin?
Chemicals that defend against pathogens. Perspiration secreted by sweat glands has salt, which inhibits the growth of pathogens. Antimicrobial peptides act against microorganisms. Lyzsozyme destroys cell wall of Gram (+) bacteria. Sebum secreted by glands helps keep skin pliable and less likely to break or tear and loweres skin pH to a level inhibitory to many bacteria.
What is the rule of mucous membranes in innate immunity?
Epithelial cells are tightly packed to preven the entry of pathogens. Continual shedding of cells carries away microorganisms.
What is the role of the lacrimal apparatus in innate immunity?
produces and drains tears, blinking spreads tears and washes surface of the eye. tears contain lysozymes.
What is the role of normal microbiota in innnate immunity?
they compete with potential pathogens, they consume the nutrients so that there aren't any left for pathogens, they create an unfavorable environment, they stimulate the body's second line of defense, they promote overall health by providing vitamins
What is microbial antagonism?
Normal microbiota are competing with potential pathogens
How do antimicrobial peptides act?
- they are present in the skin, mucous membranes, and neutrophils
- -induce holes in bacterial membranes
- -intracellular killing
When does the body's second line of defense activate?
when pathogens penetrate the skin or mucous membranes
What is the body's second line of defense?
- 1. Phagocytic cells (blood and tissues)
- 2. Nonspecific chemical defenses against pathogens
- -complement proteins (serum)
- -antimicrobial peptides (all body secretions)
- -interferons (3 types)
- 3. Inflammation (fever)
What are Interferons?
natural antiviral mechanisms that every cell in our body contains
What is plasma?
mostly water containing electrolytes, dissolved gases, nutrients, and proteins
What is serum?
the fluid remaining when clotting factors are removed. it includes iron-binding compounds, complement proteins, and antibodies
What are formed elements and what are the 3 types?
- Cells and cell fragments.
- 1. erythrocytes
- 2. platelets
- 3. leukocytes (divided into granulocytes and agranulocytes)
What is hematopoiesis?
the formation and development of cells of the blood
What are the 3 types of Granulocytes and how do they stain?
- –Basophils – stain blue with basic dye methylene blue
- –Eosinophils – stain red/orange with acidic dye eosin
- –Neutrophils – stain lilac with mix of acidic and basic dyes
How do neutrophils and eosinophils work?
- –Phagocytize pathogens
- –Capable of diapedesis (Chemotaxis)