Ch. 16 - Innate Immunity: Non-Specific Defenses of The Host Flashcards
Define: immune system
protects the human host
Define: immunity
ability to fight-off pathogens and prevent disease
Define: Resistance
host having immunity (no DZ)
Define: Susceptibility
host lacking immunity (yes DZ)
Define: Host Defense
ability of host to remove pathogen(s) in order to prevent disease
if host defenses are successful = host has immunity/resistance = no DZ
if host defenses are not successful = host is susceptible = DZ
having host defense = having ___________ = having ____________
having host defense = having immunity= having resistance
Name and GENERALLY describe the two types of host defenses/immunity
(Description and what they are AKA)
Innate Immunity
- immunity or resistance to any pathogen; gets rid of all pathogens
- AKA non-specific immunity (bc immunity doesn’t discriminate and will get rid of every pathogen; not picky)
Adaptive Immunity
- immunity or resistance to a specific pathogen (ex: only rid of fungi/only rid of gram - bacteria)
- AKA specific immunity (immunity discriminated and gets rid of selected pathogens; picky)
In detail, describe Innate Immunity (type of host defense)
AKA, presense, recognition, memory response, immune response, composition
Innate Immunity:
- AKA “Non-specific” Defenses of the Host (immunity)
- Host defenses present at birth
- No immunological memory response (bc never seen pathogen before; 1st encounter)
- Rapid immune response
- Composed of 1st and 2nd Lines of Host Defense
What type of host defense do newborns immediatley have? What is the purpose of this?
Innate Immunity because when babies are born, they are exposed to many new pathogens and need to be able to quickly fight off and kill those pathogens to survive and adapt.
Without this, many babies would die.
In detail, describe Adaptive Immunity (type of host defense)
AKA, presense, recognition, memory, immune response, composition
Adaptive Immunity
- AKA “Specific” Defenses of the Host (immunity)
- Host defenses develop later to handle a speciifc microbe
- Specific recognition and response to specific microbe
- Has immunological memory (have seen same pathogen in the past)
- Slower immune response (than innate immunity)
- Composed of 3rd Line of Host Defenses
What consists of the 1st line of defense?
Is the 1st line of defense a part of Innate Immunity or Adaptive Immunity?
- physical barriers
- chemical barriers
- biological barriers
Innate Immunity
What consists of the 2nd line of defense?
Is the 2nd line of defense a part of Innate Immunity or Adaptive Immunity?
FFIPA
- Formed elements
- Fever
- Inflammation
- Phagocytosis
- Antimicrobial substances
Innate Immunity
What consists of the 3rd line of defense?
Is the 3rd line of defense a part of Innate Immunity or Adaptive Immunity?
- Humoral immunity
- Cell-Mediated immunity
Adaptive Immunity
Name the examples of physical barriers
MILCS
- Mucous membranes
- Intact skin
- Lacrimal apparatus
- Ciliary escalator
- Saliva, urine, and vaginal secretions
Describe this example of physical barriers (ex: description and how it functions as the first line of defense against pathogens): Intact Skin
Intact Skin
- Multiple layered, closely packed epithelial cells
- Keratin protein on top layer reinforces the skin
- Dry = pathogens require moisture
- Shedding of top layer = pathogens fall off
Describe this example of physical barriers (ex: description and how it functions as the first line of defense against pathogens): Mucous Membranes
Mucous Membranes
- epithelial layer that lines gastrointestinal, respiratory, and genitourinary tracts
- secrete viscous fluid, called mucus = traps and rids of pathogen
Describe this example of physical barriers (ex: description and how it functions as the first line of defense against pathogens): Ciliary Escalator
Cilary Escalator
- epithelial cells of lower respiratory tract (airways) contain cilia
- cilia move together and sweep the mucus up (in one direction), towards the throat and out of the body = rid of pathogen
Describe this example of physical barriers (ex: description and how it functions as the first line of defense against pathogens): Lacrimal Apparatus
Lacrimal Apparatus
- protects eye
- tears = flushing mechanism/washing action = rid of pathogens
Describe this example of physical barriers (ex: description and how it functions as the first line of defense against pathogens): Saliva, Urinary, and Vaginal secretions
Saliva, Urinary, and Vaginal Secretions
- flushing mechanism
- washied away pathogens from mouth, urethra, or vagina
Name the examples of chemical barriers
- Chemical Factors of the skin
- Lysozymes
- Gastric juices
- Blood transferrins
Describe this example of chemical barriers (ex: description and how it functions as the first line of defense against pathogens): Chemical factors in and on the skin
Chemical Factors In and On the Skin
- pH: slightly acidic = bact. don’t like acidity enviornment
- Salinity (most bact. NOT halophiles; hypetonicity of skin will cause pathogen cell to shrink)
- Sebum (waxy lipid) = lowers pH of skin
Describe this example of chemical barriers (ex: description and how it functions as the first line of defense against pathogens): Lysozymes
Lysozymes
- Enzymes found in body secretions (sweat, tears, saliva)
- Break chemical bonds in peptidoglycan (in cw) = destroy bacterial cell wall
Describe this example of chemical barriers (ex: description and how it functions as the first line of defense against pathogens): Gastric Juices
Gastric Juices
- produced by stomach
- contiains enzymes and acid
-> HCl = destroy bacteria
Describe this example of chemical barriers (ex: description and how it functions as the first line of defense against pathogens): Blood transferrins
Blood transferrins
- are proteins (made by humans) that circulate in blood and bind to iron = remove iron
- Iron is micronutrient that is necessary for bacterial growth
-> Blood transferrins in blood = bind to iron = no more iron = no more bacterial growth
Name the example of Biological Barriers
Normal Microbiota
-> commensal microbes and beneficial microbes (types of NM)
-> competitive exclusion
Compare Commensal Microbes to Beneficial Microbes
(description and examples)
Commensal Microbes
- one organism benefits while the other organism (host) is unaffected (no benefit to host)
- ex: microbes on skin and in gastrointestinal tract
Beneficial Microbes
- microbes provide something to the host
- ex: vitamin K by E. coli in gastrointestinal tract (helps w blood clotting)
Describe Opportunistic Microbes
Opportunistic Microbes = NOT NORMAL MICROBIOTA❗
- microbes that act as pathogens under certain circumstances -> bc they were removed from their normal microbiota
-> Ex: E. coli introduced into urethra = DZ
Describe Competitive Exclusion of normal microbiota
(AKA, desccription)
Competitive Exclusion
- AKA “microbial competition”
- Normal microbiota complete with pathogens (invading microbes), leading to a decreased population of pathogenic bacteria (NM outcompete invading pathogens)
How do normal microbiota defeat/outcompete invading pathogenic bacteria?
- NM multiply and take up all the space for growth (no more growth of pathgens)
- take up all the nutrients
- produce substance harmful to invading pathogens
Describe this example of the 2nd line of Host Defense (ex: description, examples): Formed Elements in Blood
Formed Elements
- cells and cell fragments suspended in plasma
-> Erythrocyte (cell): contain Hb that binds to O2 and CO2
-> Leukocyte (cell): involved in immune response
-> Thrombocyte (cell fragment): inv blood clotting upon injury
- created in red bone marrow stem cells via hematopoiesis
Why is a thrombocyte not a cell?
Thombocytes are piecees/cell fragments from the megakaryocyte cell
What families can Leukocytes divide into?
Name everything that is contained within each family
Granulocytes (BEN)
- Basophils
- Eosinophils
- Neutrophiles
Agranulocytes
- Monocytes/Macrophages
- Lymphocytes
-> B Lymphocytes (Adaptive Immunity)
-> T Lymphocytes (Adaptive Immunity)
-> NK cells
Define: Granulocytes
leukocytes with granules in their cytoplasm that are visible with a light microscope
Describe the function of Basophils
What family are they from?
release histamine (granule that leads to allergy symptoms); inv in allergic response
Granulocyte
Describe the function of Eosinophils
What family are they from?
produces toxins against parasites and worms
Granulocyte
Describe the function of Neutrophils
What family are they from?
phagocytic; work in early stages of infection (first to appear at site of infection; first responder)
Joshua has just been admitted into the hospital due to illness. A blood sample is taken from him and the phlebotomist notes that he has a very high neutrophil count. What can be said about his infection? (Is it an early infection or late infection, and why?)
Early infection because neutrophils are first responders and work in the early stages of infection, therefore, high neutrophil count indicates that it is a early/recent infection.
If it were a low neutrophil count, it would indicate that it is a late infection.
Define: Agranulocytes
leukocytes with granules in their cytoplasm that are not visible with a light microscope
What is the function of Monocytes?
What family are they from?
travel in blood and will mature into macrophages in tissues where they become phagocytic cells
Agranulocyte
T/F: Monocytes are phagocytes that are found in tissue
False, monocytes are found in blood and they mature into macrophages that are capable of phagocytosis in tissue
Know the abundance of trends of leukocytes
Never Let Monkeys Eat Bananas
Neutrophil (most common)
Lymphocyte
Monocyte
Eosinophil
Basophil (least common)
Provide three examples of phagocytes. Which phaogcyte appears first during an infection?
Neutrophils - appeats first during infection
Macrophages
Dendritic cells (in skin cells)
Define Phagocytosis and Phagocyte
Phagocytosis: ingestion of microbes/substance by phagocyte
Phagocyte: non-specific host cell (innate) capable of phagocytosis
-> Ex: Neutrophil, Macrophage, Dendritic cells
Describe the phases of Phagocytosis
Chemotaxis
- release of chemical signals (cytokines) by pathogen -> attracts phagocyte
Adherance
- attachement of phagocyte to surface of the pathogen
Ingestion
- endocytosis of pathogen forms a phagosome (vesicle with pathogen inside)
- phagosome merges with lysosome (contains digestive enzymes) and forms a phagolysosome inside the phagocyte
Digestion
- pathogen is digested inside the phagolysosome (bc of digestive enzymes of lysosome)
Differentiation between phagosome and phagolysosome
Phagosome = vescicle inside phagocyte containing pathogen
Phagolysosome = phagosome + lysosome
What are three ways that microbes can evade phagocytosis.
Provide speicifc examples of microbes
Capsule
- pathogen too big to be englufed
-> ex: streptococcus pneumoniae (has largest capsule)
Leukocidins
- pore-forming toxin capable of killing phagocytes
-> Genus Staphylococcus
Mycolic Acid
- waxy lipid that inhbits lysosome digestive enzymes of phagocyte (bacteria do NOT get ingested)
- bacteria multiply inside phagocyte and hide from immune system
-> Genus Mycobacterium
Inflammation is due to _______ and __________.
injury (bc pathogen)
infection
What is the general goal of inflamation?
get rid of pathogen first, then tissue can heal
Name the signs and symptoms of inflammation
Pain
- due to release of certain chemicals (cytokines, that damage nerve endings of sensory nerves) by leukocytes
Redness/Erythema (KNOW SCIENTIFIC TERM)
- blood (caryring neutrophil and monocyte) goes to affected areas
Immobility
- loss of fxn in severe inflammation
Swelling/Edema (KNOW SCIENTIFIC TERM)
- due to accumulation of fluids
Heat
- increase BF to affected area
Describe the process of Inflammation
- Tissue or cells get damaged/infected
- Damanged cells release cytokines (chemicals)
- Cytokines promote chemotaxis of phagocyte
- Phagocytes squeeze through blood vessel and move to site of tissue injury
- Phagocytosis of invading pathogens begin
- Tissue gets repaired
Describe the process of a Fever
Define and know the correct order/sequence of chills, fever, and crisis
- Toxins are released by bacteria, which induces cytokine release from phaogcytes
- Cytokines bind to hypothalamus receptors and increase the set point for body temperature
- The “new” set point now make the person feel cold (chills) and person increase their body temperature
- Once “new” set point is reached, person experiences abnormally high body temperature (fever)
- As pathogens are eliminated, toxins and cytokines get eliminates
- Body thermostat is reset -> body temp falls -> decline of fever is called crisis
What are the outcomes/consequneces of a Fever
Enhances immune response
- promote activity of phagocytes
Increases metabolic rate
- ex: catabolism promotes cellular respiration -> ATP production
Induces antimicrobial substances
- released by certain cells
Name two “examples” of Anitmicrobial Substances
Complement System
Interferons
Describe the Complement System
(What is it? What does it act as?)
Serum proteins (complement proteins) that enhances the immune system in destroying pathogens
Complement proteins act in a cascade manner in a process called complement activation (complement proteins must first be activiated; can exist in active/inactive form)
What are the three outcomes of Complement Activation
Opsonization
- complement proteins coat surface of pathogen
- promotes attract/attachment of phagocyte to pathogen
Inflammation
- complement proteins bind to mast cells (leukocyte)
- mast cells release histamine -> increases BV permeability (leaky; phagocytes able to squeeze to site of injury)
- Chemotactic attraction of phagocytes
Cytolysis
- complement proteins create a membrane attack complex (MAC)
- MAC creates a hole/channel in pathogens cell wall/membrane -> fluid enters the pathogen -> pathogen bursts
What are the three ways microbes can evade the complement system?
Capsule Production
- Complement proteins cannot bind easily
Inhibition of MAC formation
- enzymes from bacteria prevent MAC assembly
Inactivation/destruction of complement proteins
- bacteria produces protease (enzyme) that destroys proteins, like complement proteins
Describe Interferons
(What are they and what do they do?)
small proteins produced by some animal host cells upon animal viral infection
antiviral action where IFNs alert unaffected neighboring animal cells to heighten their anti-viral defenses (warns them about possible viral infection)
Describe the mechanism of action of Interferons
- Animal virus enters animal host cell and multiplies
- Animal host cell produces IFNs (serve as signal to uninfected neighboring animal cell for potential viral infection)
- IFNs released by infected animal host cell -> bind to cell membrane of uninfected neighboring animal cell -> makes anti-viral proteins (AVPs)
- Newly released viruses that infect enighboring animal cells has AVPs waiting to destroy virus
Are formed elements a part of innate immunity, adaptive immunity, or both?
Both, because formed elements include leuckocytes which contains lymphocytes that have B and T cells that function in adaptive immunity.
