Chapter 17: The Immune System

BIOS 213

Lymphoid organs -

organs where lymphocytes develop, reside, or carry out an immune response

two categories of lymphoid organs:

primary and secondary

primary lymphoid organs -

sites where stem cells divide and devleop into B and T cells

secondary lymphoid organs -

sites where most immune responses occur

primary lymphoid organs:

bone marrow and thymus

bone marrow -

produces mature B cells and immature T cells

immature T cells from the Bone marrow go to the:

thymus

The thymus is located above the ____

heart

the thymus contains:

T cells, scattered dendritic cells, epithelial cells, and macrophages

T cells mature in:

thymosin and thymopoietine

the thymus ___ after maturity

atrophies

secondary lymphoid organs:

lymph nodes, spleen, lymphoid nodules

lymph nodes ___ a hard capsule

have

lymph nodes are scattered throughout:

lymphatic vessels of the body

Lymph nodes contain:

filter microbes

filter microbes -

macrophages and lymphocytes in lymph nodes that destroy filtered microbes

filter microbe function:

filter lymph

lymph node count:

600+ ( in clusters )

the spleen is the ___ lymphoid organ

largest

spleen function:

removes microbes and aged or defective erythrocytes

lymphoid nodules ___ a hard capsule

do not have

lymphoid nodules -

clusters of immune cells

lymphoid nodules include:

all the above

T cells ___ part of innate immunity

are NOT

innate immunity is also referred to as:

non-specific

innate immunity -

ability of body to defend itself against microbes and other foreign substances, without the use of specific recognition of an invading pathogen

innate immunity can defend against microbes ___ specific recognition

without

epitopes are found in/on:

cell membrane of pathogens

epitopes allow:

lymphocytes to recognize pathogens as a foreign organism that must be destroyed

innate immunity has one or two lines of defense?

two lines of defense

Innate immunity’s first line of defense:

external physical and chemical barriers

Innate immunity’s second line of defense:

various internal defenses

innate immunity defenders include:

all of the above

all nonspecific defenses are considered innate defenses

true

all nonspecific defenses work against all potential invaders

true

All nonspecific defenses are present at birth

true

All nonspecific defenses provide immediate protection

true

Innate Immunity’s first line of physical defense includes:

all the above

the epidermis of skin includes:

all the above

Keratinocytes -

shed and provide water-proof barrier

Langerhans cells -

make immune system aware that microbes have entered skin

Melanocytes -

release melanin and protect skin from UV light

the dermis of skin contains:

fixed macrophages that phagocytize pathogens

Mucus membranes -

secrete mucus that traps pathogens

Mucus membranes location:

both

mucocliliary escalator -

cilia in respiratory tract move mucus and trapped particles up the airways to the throat, where it can be swallowed or coughed out

Innate Immunity’s first line of chemical defense includes:

all the above

sebum -

oily substance that creates barrier over skin produced by sebaceous glands

Sebum function:

both

lysozyme function:

digest cell walls of bacteria

Lysozyme is present in:

tears, saliva, sweat, nasal secretions, and tissue fluids

gastric juice function:

acidity destroys pathogens

vaginal secretions function:

acidity prevents bacterial growth

the second line of defense contains:

all the above

the three main internal antimicrobial proteins that form the second line of defense:

all the above

interferons -

proteins produced by viral-infected cells the interfere with viral replication

interferons produce:

anti-viral proteins

complement -

a group of plasma proteins activated by antibodies binding to antigens; produced by the liver

complement is part of the:

nonspecific defense system

complement proteins are designated

C1-C9

C1 -

recognition protein

C2, C3, C4 -

activators

C5-C9 -

attacks by creating a membrane attack complex that attaches to a cell membrane and destroys it

complement activity is triggered by two pathways:

classic and alternate pathway

classic complement pathway -

binding of antibodies (IgG and IgM) to antigen

alternate complement pathway -

unique polysaccharides on bacterial membranes

complement enhances inflammation by:

increasing the release of cytokines from histamine mast cells

complement enhances phagocytosis by:

coating pathogens and opsonization

opsonization -

immune process where opsonins coat a pathogen or damaged cell, tagging it for destruction

iron-binding proteins -

transferrins; reduces amount of available iron

antimicrobial proteins -

kill microbes and attract immune cells (dendritic and mast cells)

dendritic cells are located within:

lymph organs

Mast cells are located within:

skin

antimicrobial proteins include:

dermicidin, defensin and cathelicidin, thrombocidin

dermicidin:

produced by sweat glands

defensin and cathelicidin:

produced by neutrophils, macrophages, and epithelial cells

thrombocidin:

produced by platelets

natural killer cells make up ___ of lymphocytes

5-10%

natural killer cells -

nonspecifically kill infected cells, cancer cells, and any cell with abnormal identity protein

natural killer cells include:

perforins and granzymes

perforins -

makes infected body cell membrane leaky by forming a channel

granzymes -

cause apoptosis by penetrating infected body cell via perforin channel

natural killer cells have a:

major histocompatibility complex

phagocytes perform phagocytosis through:

adherence → ingestion → digestion → killing

Phagocytes include:

neutrophils and macrophages (fixed and wandering)

macorphages are located in:

skin, liver (kupffer cells), lungs, nervous system (microglia), spleen, lymph nodes, red bone marrow

in phagocytosis:

a lysosome attaches to a phagosome and digests it

inflammation -

non-specific response to tissue damage

inflammation includes 4 distinct signs and symptoms:

redness, pain, heat, swelling

redness is caused by:

vasodilation

pain is caused by:

local mediators, kinins; severe swelling

heat is caused by:

vasodilation

swelling is caused by:

increased capillary permeability

stages of inflammation

vasodilation, emigration of phagocytes, tissue repair

during inflammation, ___ are the first to show up

neutrophils

Vasodilation allows for:

more blood flow to the site

increased permeability allows for:

defensive immune substances to leave the cardiovascular system and go to the damaged site

permeability changes caused by local mediators like:

histamine, kinins, prostaglandins, leukotrienes, and complement

histamine effects permeability by:

vasodilation

kinin effect permeability by:

binding at nociceptors