Fundamentals of Host Defenses Flashcards
immunity
ability of a host to resist infection or disease
immunology
study of immune responses
innate immunity
built in ability of the immune system to target pathogens
adaptive immunity
ability of immune system to target a particular pathogen
Innate Immunity: Barrier
skin
largest organ, mechanical barrier
Innate Immunity: Barrier
epidermis
outer layer compsed of tightly packed keratinocytes
- move to top layer in. about 14 days
Innate Immunity: Barrier
stratum corneum
top layer, 15-20 layers of thick, dead cells, embedded in lipid matrix that is acidic
Innate Immunity: Barrier
dermis
connective tissue, sweat glands, hair follicles
Innate Immunity: Barrier
sebum
produced by sebaceous glands, rich in fatty acids
Innate Immunity: Barrier
sweat
produced by sweat glands, makes skin hypertonic to microbial cell cytoplasm
Innate Immunity: Barrier
langerhan cells
immune cells
Innate Immunity: Barrier
mucous membrances (mucosa)
epithelial cells and specialized cells that act as a barrier and trap pathogens
Innate Immunity: Barrier
goblet cells
produce mucus which includes glycoproteins, proteoglycans, lipids, proteins, and DNA which trap foreign materials
Innate Immunity: Barrier
paneth cells
secrete antimicrobial peptides and enzymes
Innate Immunity: Barrier
mucociliary escalator
coats surfaces of the lower respiratory tract, cilia ‘wave’ to move particles up
Innate Immunity: Barrier
peristalsis
columnar epithelial cells of the GI tract are shed to reduce attached microbes
Communication in the immune system
cytokines
generic term for soluble, low weight proteins or glycoproteins that serve as intercellular signaling molecules
Communication in the immune system
JAK-STAT
- signal transduction pathway
- phosphorylation of Janus Kinase
Host micrbiome
holobionts
host and its microbes who have evolved together and form a single functional unti
Host micrbiome
microbial antagonism/bacterial interference
adaptations in which one microbe inhibits the growth or kills a competing microbe
Host micrbiome
virome
entire population of viruses within a particular host
Host micrbiome
gut-brain axis
metabolites produced by the microbiome impact behavior
Cells of the immune system
leukocytes
white blood cells
Cells of the immune system
granulocytes
contain cytoplasmic inclusions which contain toxins or enzymes that are visible on stained blood smears
Cells of the immune system: granulocytes
mast cells and basophils (<1% of WBCs)
- not phagocytic
- associated with allergies
- undergo degranulation
Cells of the immune system: granulocytes
degranulation
release of vasoactive mediators which influence blood vessels and the inflammatory response
Cells of the immune system: granulocytes
eosinophils (2-4% of WBCs)
- weak phagocytes
- secrete cytotoxic enzymes that target larger, extracellular pathogen
Cells of the immune system: granulocytes
neutrophils (50-65% of WBCs)
- highly phagocytic
- highly motile
- circulate in blood and migrate to infected tissues
- NETs (neutrophil extracellular traps) of DNA can trap extracellular pathogens
Cells of the immune system: monocytes
macrophages (2-9% of WBCs are monocytes)
monocytes develop from myeloid precursor and develop into macrophages in the blood
Cells of the immune system: monocytes
dendritic cells
have vast surface area due to cellular projections
Cells of the immune system: lymphoid cells
innate lymphoid cells
include NKs and other lymphoid precursor derived cells involved in innate immunity
- aid in lymph development
- activate macrophage
- trigger vasodilation, mucus secretion, release antimicrobial peptides
Cells of the immune system: lymphoid cells
Natural Killer cells
- detect kill or don’t kill signals from host cells
- stimulate apoptosis in cells determined to be stressed, malignant, or virally infect
Cells of the immune system: lymphoid cells
T cells
recognize antigens displayed on host cells via glycoproteins called the MHC
t cell receptors
bind to antigens specific to a particular pathogen and stimulatet t cell activation and cytokine production
Cells of the immune system: lymphoid cells
B cells
produce antibodies that neutralize and/or tag antigens for destruction
Organs and tissues of the immune system
primary organs and tissues
where HSCs differentiate into immune cells
Organs and tissues of the immune system: primary
bone marrow
site of b cell development and selection during which self-reactive B cells are eliminated
