Lecture 8: Innate Immunity Flashcards
The _____ fights off foreign material that threatens the body
immune system
what are the two branches of the immune system?
innate immunity
adaptive immunity
innate immunity is _____
non-specific
adaptive immunity is _____
highly specific
T/F: innate immunity is always the same from birth to forever
true
innate immunity is natural host resistance and has no _____
memory
Pathogens prefer a _____ body site to initiate infection
specific
how do pathogens pick a specific body site to initiate infection?
Based on nutritional and metabolic needs
Mechanism of spread
* Aerosols vs blood/bodily fluids
T/F: Susceptibility to pathogens varies from one species to another
true!
natural host resistance always plays a part in infectivity!
ex: Anthrax causes fatal blood infection in cattle and cutaneous infection in
humans
HIV can infect human cells but not mice or guinea pigs
what are the two physical barriers we have to prevent infection?
skin and mucous membranes
______: Prevents invasion by microbes
Rich in tough protective protein
* Keratin
Slightly acidic ~pH 5
High [NaCl]- periodic drying
Some fungal infections can grow right on the _____’s surface
* Many require broken _____ in order to penetrate and cause infection
skin
T/F: skin is an organ because it consists of two+ types of tissue
true!
why does our skin have high [NaCl]?
because it dries our skin out, which in turn dehydrates bacteria and limits their growth! how we protect ourselves!
______: Line tracts in the body
- Respiratory tract, digestive tract, reproductive tract, urinary tract
- _____ produced by goblet cells
- Traps microbes preventing
infection - Contains antimicrobial secretions
mucous membranes
T/F: mucous membranes are not open to the outside environment
false!
______: Contains the mucocilliary escalator
* Mucosal epithelial cells contain cilia
* Serve to filter incoming air
* Sweeping action of cilia allows the removal of mucous and trapped microbes from the
lungs
respiratory tract
what two parts of our body compose the gastrointestinal tract?
stomach and small intestine
______: Strongly acidic: pH~2
* Contains proteases
* Few microbes are able to survive in this
environment
part of the gastrointestinal tract
stomach
______: Pancreatic juice buffers acidity of incoming
contents from the stomach: pH ~7
* Contains pancreatic enzymes
* Contains bile from the liver
* Very difficult for microbes to maintain cellular integrity in this harsh environment
part of the gastrointestinal tract
small intestine
why is the stomach strongly acidic?
low pH denatures proteins, exposes cut sites for proteases to destroy organic material
______: Contains the normal microbiota
Normal resident bacteria that live symbiotically inside of the colon
Use attachment sites to persist
Consume undigested nutrients
* Competitive exclusion
Produce antimicrobial compounds
* Microbial antagonism
large intestine (colon)
T/F: the large intestine has more bacteria than human cells
true!
why can one person absorb many more calories from the same meal as another person?
we don’t have transporters in the colon, so we’re done absorption of nutrients
BUT if the bacteria in our colon produce non-polar waste products, we CAN absorb those through membranes! which adds to the total calories absorbed
gut flora affects obesity!!
what does competitive exclusion in our colon mean?
there’s no space for bad bacteria (in an environment they would LOVE to colonize)… our good bacteria out-compete them! however, if we take anti-biotics and wipe out our normal flora… bad guys can move right in!
what does microbial antagonism mean?
bugs create poisons/toxins that destroy other bugs to wipe out their competition
_______:
Genital and urinary tracts are separate in females
and joint in males
Urinary tract contains urine
* Includes many toxins that are intolerable by bacteria
The act of urination physically removes contaminating microbes
The female reproductive tract contains normal microbiota
* Glycogen secreted by vaginal epithelial cells
supplies nutrients for microbial growth
genitourinary tract
why do women have Lactobacillus acidophilus in their vagina?
ferments glucose to lactic acid, drops pH to ~4.5, provides a defense against sexually transmitted infections/diseases
______: Composed of organs and vessels that allow immune cells to contact foreign antigenic material
lymphatic system
An _____ is foreign material that is able to activate cells of the immune
system
antigen
what are the two components of the lymphatic system?
lymphatic vssels
lymphoid organs
________: Carry lymph from the tissues to the lymph nodes
* Unidirectional (always away from tissues)
* Lymph is rich in leukocytes (white blood cells)
* Free of erythrocytes (red blood cells)
lymphatic vessels
T/F: there are primary and secondary lymphoid organs
true!
what are the primary lymphoid organs?
bone marrow
thymus gland
what are the secondary lymphoid organs?
**All contain a high concentration of leukocytes
lymph nodes
spleen
mucosa associated lymphatic tissue (MALT)
_____: Leukocytes are produced here
bone marrow
make all our blood cells here!
_____: Some leukocytes mature here
thymus gland
where do B-lymphocytes mature?
bone marrow
where do T-cells mature?
thymus gland
______: Associated with all mucous membranes
MALT (mucosa associated lymphatic tissue)
_____: Leukocytes present here are constantly
phagocytosing material in their surroundings
in search of foreign content
GALT (Gut associated lymphatic tissue)
what are the main cells that form our cellular defenses?
leukocytes
______: Circulate in the blood and the lymphatic system
* Reside in the tissues and the lymph nodes
* Play a role in both innate and adaptive immunity
leukocytes (white blood cells)
what are the two broad categories of leukocytes?
granulocytes and agranulocytes
______: Large, visible granules in the cytoplasm
Granules are reactive
* Can kill microbes
* Can serve as signaling molecules to recruit
and activate other components of the
immune system
granulocytes
what are the three types of granulocytes?
neutrophils, eosinophils, basophils/mast cells (BEN)
______: Cytoplasmic granules contain
* Lysozyme
* Defensins
Circulate in the blood
* Exit the capillaries during
periods of infection
Strongly phagocytic
Very important cells of the innate immune system
neutrophils
why are neutrophils able to exit the capillaries during periods of infection?
capillaries become leaky when vasodilation occurs in response to injury, lets these big clunky neutrophils through to combat infection
______: Non-phagocytic cells
Cytoplasmic granules will stain with acidic dyes
Work to destroy large parasitic cells
* Protozoa and parasitic worms
* Secrete extra-cellular enzymes and reactive oxygen
species
* Can also exit the capillaries into infected tissues
eosinophils
_______: Cytoplasmic granules stain with basic dyes
Not strongly phagocytic
Basophils circulate in the blood
Mast cells reside in mucosal tissue
Degranulate in response to appropriate stimuli
* Release histamine
* Important part of the allergic response
* Causes vasodilation locally
* Causes life threatening vasodilation and
bronchiolconstriction when released systemically
basophils and mast cells
basophils are found where?
the blood
mast cells are found where?
in tissue
when vasodilation occurs, what happens in the blood? why do people go into multiple organ failure?
when vasodilation occurs, flow increases but pressure drops, causes multiple organ failure when blood is not reaching vital organs (especially our brain!)
________: Contain cytoplasmic granules that are much
smaller and more difficult to view than granulocytes
agranulocytes
what are the two types of agranulocytes?
monocytes
lymphocytes
what are the two types of monocytes?
macrophages
dendritic cells
_______: Located in the tissues
* Lungs, connective tissue, spleen, liver
Contain special surface receptors that allow them to
recognize many pathogens with one receptor
* Toll-like Receptors (TLRs)
* Recognize things like LPS, peptidoglycan, elements of the fungal cell wall
Binding of the toll-like receptor to antigen
induces phagocytosis
macrophages
T/F: macrophages have toll-like receptors which are very specific
false! non-specific recognition, don’t care WHO it is, just that macrophage needs to bind and destroy
_______: Found in tissues that are often sites of entry for
infectious materials
* In the skin they’re called Langerhan’s Cells
Also found in the mucus membranes of the nose, the
lungs and the intestines
Regularly sample the surroundings and phagocytose antigens
* Phagocytosed antigen is carried to lymphoid organs
* Presented to other cells of the immune system
(T/B lymphocytes)
* Activate the adaptive immune response
dendritic cells
when dendritic cells pull bacteria off of our skin in advance to show our immune cells and teach our immune system how they work, this is an example of what kind of immunity?
adaptive immunity
______: Leukocytes the are involved in the adaptive immune response
Circulate through the blood and remain in the lymphoid organs
lymphocytes
what are the three different kinds of lymphocytes?
B lymphocytes
T lymphocytes
Natural Killer Cells (NK)
_____: Also called B cells or plasma cells
* Antibody producing/secreting cells
* Form the main component of humoral immunity
B lymphocytes
_______: Also called T cells
* Different types
* Form the main component of cell mediated immunity
T lymphocytes
______: Destroy abnormal cells in the body (cancer cells, infected cells)
Natural Killer cells
when we have swollen lymph nodes what is this an indicator of?
an immune response, our lymphocytes are proliferating (rapid cell division) to mount an immune response
where do B lymphocytes mature? where are they made?
in bone marrow
where are T cells made? where do they mature?
made in bone marrow, mature in thymus gland
T/F: Natural Killer cells kill our own cells!
true! destroy our OWN abnormal cells
T/F: molecular defenses are just one single molecule
true!
molecular defenses are secreted where?
mucosal sites
what are two examples of molecular defenses secreted at mucosal sites?
lysozyme
defensins
______: Cuts b-1,4 glycosidic bonds in peptidoglycan
lysozyme
______: Antimicrobial peptides that poke holes in bacterial cell membranes
inside granules in neutrophils
defensins
_____: Destroys pathogens that may have never before
been encountered in the body
phagocytosis
phagocytosis involves capable leukocytes, what are they?
neutrophils and macrophages
___ and ____: Recognize pathogen associated molecular patterns (PAMPS)
* Lipopolysaccharide, lipoteichoic acid, flagellin
to perform phagocytosis
neutrophils and macrophages
PAMPs are recognized by ___s located on the
surface of phagocytic cells
TLRs also known as pattern recognition receptors (PRRs)
Interaction of PAMP with a TLR triggers _____
phagocytosis
explain the process of phagocytosis
Cell membrane invaginates around a foreign particle
Engulfs it into a phagosome
Phagosome fuses with a lysosome to form a phagolysosome
Oxygen independent killing
Neutrophils perform exocytosis
* Fragments are expelled from the cell
Macrophages and Dendritic cells become antigen
presenting cells
* Fragments of the intruder are presented on the cell surface to trigger an adaptive immune response
what are lysosomes filled with?
Lysozyme and defensins
Proteases (degrade proteins)
Lipases (degrade phospholipids)
Nuclease (degrade nucleicacids)
______: Activated phagocytes produce reactive oxygen
compounds:
* H2O2, O2, OH, HOCl, NO
Kill ingested microbes by oxidizing cell components
oxygen dependent killing
_____: Occurs non-specifically in response to tissue
damage, toxins, and infectious material
inflammation
what are the five cardinal signs of inflammation?
Redness (erythema), warmth, pain, swelling
(edema) and loss of function
In response to infection injured tissue and
leukocytes release _____
pro-inflammatory
cytokines
what do pro-inflammatory
cytokines do?
cause blood vessels to dilate (vessel walls become more permeable… no more pressure of inflammation of blood vessel), allow more leukocytes to access the area where they can attack invading pathogens
_____ increase may slow the growth of pathogens
Also promotes faster healing of damaged tissues
Temperature
Blood leaking into tissue spaces can _____
* Prevents movement of pathogens
clot
_______: An increase in body temperature
* Controlled by the hypothalamus of the brain
* It is triggered by toxins, LPS, and chemicals produced by the immune system
* All of these things reset the bodies thermostat
fever
hypothalamus is the regulator of…
homeostasis
what does a fever result in? (only up to a certain temp… above 43C can cause death)
Muscle contraction-shivering
Increased temperature-faster metabolism and promoted healing
Faster phagocytosis
Slower growth of microbes
why can fevers be lethal to humans?
because we’re made of the same material as the bacteria we’re trying to kill!
