Unit 2 - Immunology Flashcards
What is susceptibility
Vulnerability or lack of resistance
What is resistance
Ability to ward off disease through our defenses
What are the two different types of the body’s defenses
Non specific defences (innate)
Specific defences: immune response (acquired)
What is the first line of defence
Skin and mucous membranes, normal microbial flora
What is the second line of defence
Phagocytes, inflammation, fever, and antimicrobial substances
What is the third line of defence
Acquired immunity: lymphocytes and antibodies
What defences are considered non specific
1 and 2nd
What defences are considered specific
3rd line
What do non specific defences do
Protect us against any pathogen
Acts in the same way regardless of the pathogen
What is the mechanical process of the first line of defence
Physical barriers to entry or processes that remove microbes from body’s surface
What is the chemical form of the first line of defence
Substances made by the body that inhibit microbial growth and destroy them
Describe general characteristics of skin
Largest organ
3 layers: epidermis
Dermis
Hypodermis
Describe the epidermis
Top layer, consisting of dead cells rich in keratin
Describe the hypodermis
Sub cutaneous tissues
List some of the skin defences
Dryness and acidity of skin inhibit growth.
Skin shedding removes microbes on skin surface
Sebum creates a protective film that inhibits certain bacteria
Perspiration flushes the skin and has lysozymes to break down gram + bacteria cell walls
Which bacteria is usually involved in a dermatitis
Staphylococci bacteria since it is the normal inhabitant of the skin
Describe mucus membranes
Cover respiratory, gastrointestinal and urogenital tract. Less protective than skin. Epithelial layer secretes mucus which is a slightly viscous glycoprotein. Mucus traps microbes and dust which prevents tracts from drying
Describe the ciliary escalator
Mucus membrane cells are covered with cilia that move in a wave- like motion to propel microbes and dust that become trapped in mucus upward toward the throat where it is coughed, sneezed or swallowed.
Describe saliva
Helps dilute the numbers of Microorganisms and wash them from the surface of teeth and mucus membranes in the mouth. Contains lysozymes that break down bacteria
Describe the characteristics of the stomach
Gastric secretions are a mixture of hydrochloric acid, enzymes, mucus.
High acidity destroys most bacteria and toxins
Some Microorganisms enter intestines by being protected in food particles.
Describe the characteristics of urogenital tract
Flow of urine cleanses the urethra
Vaginal secretions move Microorganisms outside the body. Also slightly acidic to inhibit bacterial growth
Describe the lacrimal apparatus
Lacrimal glands produce tears, blinking spreads the tears over the eye, tears evaporate and drain into the nasolacrimal duct
What happens in the lacrimal apparatus if irritating substances or Microorganisms done in contact with the eye
Lacrimal glands produce more tears to wash away the irritating factor. Tears contain lysozyme.
What is commensalism
One organism benefits from a larger organisms which is unaffected
Where are normal microbiota found
Skin and GI tract.
What are normal microbiota good for
Reduces area available for pathogens to attach establish. Competes with pathogens for nutrients. Produces substances harmful to pathogens.alters conditions that affect the survival of pathogens. Usually harmless but can cause disease if conditions change
Describe the second line of defense
Phagocytosis, inflammation, fever, complement system, interferons
What is Phagocytosis
Ingestion of micro organisms or particles such as debris by phagocytic cells.
What white blood cells are Phagocytic
Neutrophils, eosinoPhils, macrophages
Phagocytosis is part of what process
Inflammation
Describe neutrophils
Highly phagocytic and motile. Active in initial stages of infection. Can leave the blood and enter infected tissue to destroy microbes and foreign particles
Describe eosinophils
Somewhat phagocytic
Active in initial stages of infection.
Ability to leave the blood
Produce toxic proteins against parasites such as helminths
Discharge peroxide ions to destroy helminths.
What does having a high number of eosinophils mean
Parasitic infections and allergic (hypersensitivity reactions)
Describe macrophages
Matured monocytes
Active as infection progresses
Dispose of bacteria, worn out blood cells as infection subsides.
Involved in cell mediated immunity.
What are the two types of macrophages
Fixed and wandering
What is the other name for fixed macrophages
Histiocytes
What do wandering macrophages do
Roam the tissues and gather at sites or inflammation or infection.
What is chemotaxis
Chemical attraction of phagocytes to Microorganisms.
What are the chemotactic chemicals
Microbial products, wbc components, damaged tissue cells
Describe adherence
Attachment of phagocytes plasma membrane to the surface of the Microorganisms or other foreign material.
What is opsonization
The coating process with certain serum proteins that promote attachment of micro organism to the phagocyte
What is ingestion
Plasma membrane extends pseudopods that engulf the micro organism. The pseudopods join and fuse to create phagosomes.
Describe digestion in phagocytes
Phagosome in cytoplasm contacts lysosomes containing digestive enzymes and bacteriocidal substances. The two fuse membranes to form a phagolysosome.
What are the four mechanisms of phagocytosis
Chemotaxis, adherence, ingestion, digestion.
How do bacteria avoid distruction by phagocytosis
Have structures that inhibit adherence, some microbes can escape the phagosome before fuses with Lysozomes. so microbes can survive inside the phagocyte and require the low pH inside the phagolysosomes to replicate.
What is inflammation
Defense mechanism following tissue damage caused by microbial infection, physical agents such as heat electricity or sharp objects, or chemical agents such as acids or bases.
What are the four signs of information
Redness or Erythema, heat, swelling or edema, pain
What is acute inflammation
If the cause of inflammation is removed in a short period of time. Intense response
What is chronic inflammation
If the cause of information is difficult or cannot be removed. Longer-lasting and less intense response. Overall more destructive
What are the functions of inflammation
Destroy and remove the injurious agent if possible. If destruction is not possible, to limit the effects on the body if I can finding or walling off the injurious agent. Repair or replace damaged tissue.
What are the three stages of inflammation
Vasodilation and increased permeability of blood vessels, phagocytose migration and phagocytosis, tissue repair
Why is vasodilation part of the information process
Increased permeability permits defensive substances to pass through the walls of blood vessels and enter the injured area. Help deliver clotting elements to form a clot
What is vasodilation responsible for
The erythema and heat of inflammation.
What is increased permeability responsible for
The Edema of inflammation.
What is a localized accumulation of pus
Absess
What is vasodilation and increased permeability of blood vessels caused by
Chemicals released by damage cells in response to injury. Histamines, kinins, prostaglandins, leukotrienes.
What do histamines, kinins, prostaglandins, leukotrienes do
Attract phagocytic cells and T cells from the immune system
What is margination
When neutrophils and monocytes stick to lining of blood vessels
What is diapedesis
Phagocytes squeeze between the endothelial cells of blood vessels to reach the damaged area
What do monocytes mature into
Macrophages
What do macrophages do
Phagocytize destroyed tissues, dead neutrophils, invading Microorganisms
What do dead neutrophils and macrophages form
Pus
What happens to pus
Fistulates or is gradually destroyed and absorbed by the body
When does tissue repair start
During active phase of inflammation but is not completed until harmful substances have been removed.
When is a tissue repaired
When it’s stroma or parenchyma produces new cells
What is a stroma
Supportive connective tissue
What is a parenchyma
Functioning part of the tissue
What is fever
Abnormally high body temperature produced in response to a bacterial or viral infection.
What part of the brain controls body temperature
Hypothalamus
What does a chill in a fever mean
The body responses to cold temperature with increased blood vessel constriction, increased rate of metabolism and shivering
What is the crisis point in a fever
Where the infection subsides the body temperature lowers and he losing mechanisms such as vasodilation and sweating occur
What are two antimicrobial substances
Proteins of the complement system, interferons
What is the complement system
Complement system consists of a group of serum proteins produced by the liver that activate one another in the cascade to destroy invading microorganisms. Complement proteins are in active until they are split into products
What happens when the three complement system pathways end in the activation of C3
Inflammation,opsonization or phagocytosis, cytolysis
What are interferons
Antiviral proteins produced in response to a viral infection. Host cell specific but not virus specific
What do alpha and beta IFN interferons do
Induce uninfected cells to produce antiviral proteins that prevent viral replication
What does the gamma IFN interferon do
Activates neutrophils and microphones is to kill bacteria by phagocytolysis
