Innate Immunity

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Maya

Cards (82)

Immunology
study the immune system and immune responses
study the body's defence against infection
The physiologic function of the immune system is to prevent infections and eradicate established infections
maintains homeostasis
Immunity: resistance to disease
Immune system
functional system, rather than and organ system
the "structures" are a diverse array of molecules + trillions of immune cells that inhabit lymphoid tissues and circulate in body fluids
4 classes of pathogens
Bacteria
viruses
fungu
parasites
protozoa
worms
immunology is involved with immunoserveillance
involvement in every body system
psychoneuroimmunology
reproductive immunology
cardiovascular immunology
the lymphatic system
distributed throughout the body
consists of bone marrow, a number of structs and organs that contain lymphatic tissue, lymphatic vessels, lymph
Lymphatic tissue
specialized form of connective tissue containing lymphocytes
Lymph
clear fluid, essentially interstitial fluid that is located within lymphatic vessels and tissues
where a lot of our immune cells travel through
functions of the lymphatic system
circulate body fluids: drains excess interstitial fluid, transport lipids
defend the body against disease: initiate and coordinate immune responses
the 2 groups of lymphatic organs/tissues
primary lymphoid organs
secondary lymphoid organs/tissues
primary lymphoid organs
where pluripotent stem cells differentiate and become immunocompetent
born as immune cells then decide what they want to due in the bone marrow
where immune cells are born and develop
RED BONE MARROW and THYMUS
secondary lymphoid organs/tissues
sites where immune cells continue their maturation and are able to connect with one another to initiate adaptive immune responses
sites where most immune responses occur
LYMPH NODES, SPLEEN, LYMPHATIC NODULES/FOLLICLES
Red Bone Marrow
in flat bones and epiphyses of long bones
pluripotent stem cells give rise to mature immunocompetent B cells and immature (pre) T cells
T cells have to travel to the thymus to learn how to do their job
Thymus
bilobed organ located in the mediastinum
on the of the heart between the sternum and the aorta
where pre-T cells go to develop into mature T cells
Lymph Nodes
small organs distributed throughout the body
along the lymphatic vessels
act as filters for lymph
places where cells of the adaptive immune system "meet up"
cells have the opportunity to meet each other and deliver messages
600 lymph nodes distributed throughout the body
Spleen
largest secondary lymphoid organ
left, between the stomach and the diaphragm
one of its important functions is the removal of damaged/ defective RBCs
stores 1/3 of the body's platelets
Lymphatic Nodules
organized masses of lymphatic tissue
not surrounded by a capsule
commonly associated with mucosal surfaces (MALT = mucosal associated lymphoid tissue)
tonsils
Immune system divisions
Innate
Adaptive
Innate Immune System
non-specific
1st and 2nd line of defense
skin barriers
skin
mucous membranes
microbiota
internal defenses
phagocytes
NK cells
inflammation
antimicrobial proteins
fever
Adaptive Immune System
highly specific
3rd line of defense
specific cell types and/or proteins are generated that attack foreign substances
has memory
conferring lifelong protection
humoral immunity: B cells
cellular immunity: T cells
Innate immune system first line of defence mechanisms
skin (epidermis)
mucous membranes
mucous
hairs
cilia
tears
enzymes (lysozyme)
bodily fluids
saliva
urine
vaginal secretions
vomiting and defecation
sebum
sweat
gastric juices
Skin
Epidermis
many layers of closely packed, keratinized cells
very hard for bacteria to get through
sheds periodically, removing microbes from the surface
surface is slightly acidic so it is not inhabitable for microbes
intact skin is a very protective layer for keeping pathogens out of the body
Mucous
viscous, traps microbes and foreign substances
coughing and sneezing accelerated movement of mucous (with the trapped microbes) out of the body
swallowing mucous sends the microbes to the stomach where they're destroyed
Hairs
trap and filter microbes
Cilia
hair-like microscopic projections on epithelial surface
waving action propels the movement of mucous
wave microbe to the back of the throat
ejection/destruction of pathogens
Tears
lacrimal apparatus makes and drains tears in response to irritants
continual washing of the eye with tears keeps microbes from settling on the surface of the eye
Enzymes
Lysozyme
breaks down cell walls of certain bacteria
present in tears, saliva, sweat, other secretions
Saliva
washes microbes from the surface of the teeth and mucous membranes of the mouth
contains enzymes
Urine
flow cleanses the urinary system
Vaginal Secretions
expels microbes from the vaginal tract
slightly acidic - inhibits bacterial growth
Vomiting & Defecation
expel microbes
can be stimulated in response to bacterial toxins
Sebum
sebaceous oil forms a protective coating over the surface of the skin
contributes to the low pH of skin which inhibits bacterial growth
Sweat
flushes microbes from skin surface
contains lysozyme
Gastric Juices
strong acidity (pH 1.2-3) destroys most bacteria and bacterial toxins
Internal defences of innate system
if pathogens penetrate the surface protections, there's a second, non-specific line of defence
involves a variety of cells & factors:
antimicrobial proteins
natural killer cells
phagocytes
inflammation
Antimicrobial Proteins
a variety of antimicrobial proteins enhance innate defences by attacking microorganisms directly or hindering their ability to reproduce
Interferons
Complement
Iron-binding proteins
antimicrobial proteins
Interferons
small secreted proteins which interfere with viral replication
Complement
inactive proteins in plasma that "complement" the antibacterial activity in the body
COMPLEMENT SYSTEM: a complement cascade of plasma proteins that interact with one another
opsonize pathogens: they cover pathogens to make them more attractive for a macrophage to eat
fight infection