lymphatic system system (final)

category 1 aids

cell T > 500/ul; no symptoms, but has HIV virus

category 2 aids

T cell 200-499/ul; opportunistic disease

symptoms of category 2 aids

thrush, kaposi's sarcoma, pneumocystis pneumonia

thrush

fungal infection of mouth

kaposi's sarcoma

rare skin cancer

pneumocystis pneumonia

caused by a unicellular eukaryote (similar to a fungus)

category 3 aids

full blown aids; T cell < 200/ul

how does HIV enter the cell

HIV enters helper T cells by binding to CD4 protein

what does HIV convert to

HIV converts its RNS to cDNA using enzyme, reverse transcriptase; HIV cDNA intercalates itself into T4 DNA

what happens after HIV intercalates itself

T4 memory cells replicate the viral DNA, the virus packages itself, and bursts out of T4 cell destroying the cell

treatment of HIV

AZT, entry inhibitors and fusion inhibitors, interleukin 2, vaccine, PrEP, prevention

AZT

blocks reverse transcriptase

interkeukin 2

helps increase number of T cells

vaccine

so far unsuccessful, virus mutates rapidly

PrEP

HIV prevention method for those at highest risk; 2 anti-HIV medications

lymphatic system function

drain interstitial fluid, tansport dietary lipids, and protect against microorganisms

flow of lymph

aa> blood capillaries > interstitial spaces > lymphatic capillaries> lymphatic ducts> junction between subclavian vv and jugular vv

lymphatic vessels

resemble vv but have thinner walls, more valves, and closed at one end

lymphatic capillaries

allow fluid to flow in but not out

thymus gland is in

mediastinum

what occurs in thymus gland

T cells proliferate and mature

when does thymus gland reach maximum size

age 10-12 then begins to shrink and degenerate

lymph nodes contain

T and B cells and fixed macrophages

how does lymph flow in nodes

one direction

lymph nodes filter

pathogens before lymph passes back into bloodstream

spleen contains

2 types of tissues; white and red pulp

white pulp contains

B cells

white pulp function

functions in immunity as a site of B cell proliferation into plasma cells

red pulp contains

venous sinuses filled with RBC, macrophages, and lymphocytes

function of red pulp

functions in phagocytosis of pathogens or damaged RBCs and platelets

lymphoid tissues

tonsils

function of tonsils

immunity against oral pathogens

nonspecific/innate immunity

general protection against wide range of pathogens

specific/adaptive immunity

activation of specific lymphocytes that combat a particular pathogen

examples of nonspecific/innate immunity

skin and mucous membranes, phagocytes, immunological surveillance, interferons, complement system, inflammation, fever

examples of specific/adaptive immunity

formation of T & B cells, antigens, cell mediated immunity, antibody mediated immunity, and immunological memory

steps of phagocytosis

emigration, chemotaxis, ingestion, digestion

emmigration

phagocytes move from blood stream to area of tissue damage

chemotaxis

chemical attraction of phagocytes to location of microbe

ingestion

phagocyte extends projections called pseudopods that engulf microbe

digestion

within that phagocyte, vesicle merges with digestive enzymes, lysozyme, and lethal oxidants

what is immunological surveillance

constant monitoring of tissues by natural killer cells (lymphocyte);

what is the next line of defense

immunological surveilance and phagocytes

process of immunological surveillance

recognize abnormal cells/antigens and responds quickly before B & T cells

natural killer cells secrete

perforins

what does perforins do

create pores in target cells and cause them to lyse

compliment proteins are

inactive proteins

activation of inflammation

cause vasodilation and release of histamine form basophils

opsonization

coat pathogen and "tag" it for phagocytosis

cytolysis

several compliment proteins combine and form membrane attack complex

membrane attack complex

creates pores in cell membrane of pathogens

inflammation

response due to tissue stress

what happens after tissue damage

blood vessels dilate and histamines are released

inflammation causes

increased permeability of capillaries to allow phagocytes to move in; wbc can leak out due to permeability

endogenous antigens affect

body cells due to virus

endogenous process

virus infects body cell, cell produces viral proteins, viral proteins along with MHC 1 are presented on cell membrane

exogenous antigens affect

antigen presenting cells due to bacteria

antigen presenting cells include

B cells and macrophages

process of exogenous antigen

ingestion of antigen, digestion of antigen into fragments, APC synthesizes MHC 2 molecules, MCH 2 and antigenic fragment combine, MHC 2 and antigenic fragments presented on APC membrane

why doesn't body attack its own cells

due to MHC 1 complex; found on all body cells except RBC

purpose of MHC

present antigens so body can recognize foreign cells

MHC 1 function

pick up normal antigen and display them

MHC 2 function

found on surface of APC and lymphocytes

antigen

large molecule with simple subunits

function of antigen

helps body trigger immune response against foreign cells

antibodies

each specific for particular antigen

function of antibody

bind to target cell and disables, phagocytes will destroy cell

antibodies are made of

4 polypeptide chains; 2 heavy and 2 light chains

within heavy and light chains are

variable and constant regions

variable region

binds to antigenic determinants

hinge region

provides flexibility

cell mediated immunity begins with

activation of T cells

t cells recognize

antigenic determinants presented on APC's or infected body cells

what to t cells need

to recognize and need co-stimulation

helper t cells display

CD4 protein

what do helper T cells do

secrete cytokines/interleukins when recognize foreign antigen with MHC

what do activated helper cells do

co stimulate cytotoxic t cells and b cells

cytotoxic T cells display

CD8 proteins

what do cytotoxic t cells do

recognize antigen and MHC, bind to helper t cells, and receive co-stimulation; contain perforin to puncture target cells

cytotoxic t cells secrete

lymphotoxin

lymphotoxin

enzyme that causes DNA to fragment

memory t cells

T4 and T8; remember antigen and form clones

antibody mediated immunity

activation of B cells; recognize antigen with APC/MHC2, need cositmulation from helper t cells to become activates, divide into plasma cells which secrete antibodies, make memory b cells

natural killer cells

monitor cells; next line of defense along with phagocytes

neutrophils

phagocyte

monocytes

macrophage, undergo phagocytosis

wandering macrophages

more throughout blood, activate T cells

fixed macrophages

stay in specific location and do phagocytosis in that location

helper t cells

release cytokines to activate B cells and cytotoxic T cells

cytotoxic t cells

kill cells with perforin or lymphotoxic

memory T cells

created to remember antigen/make clones

b cells

secrete plasma cells that then secrete antibodies

memory b cells

created to remember antigen and make clones

plasma cells

secrete antibodies

primary response of immunological memory

after initial contact with antigen, takes several days for antibody concentration to increase

secondary response of immunological memory

memory cells recognize antigen and respond more quickly, responds to low levels of antigen

is primary or secondary response faster

secondary, and has greater antibody concentration

naturally acquired active immunity

constant exposure throughout life

artificially acquired active immunity

vaccines that contain weakened attenuated virus/bacteria

passively acquired immunity

antibodies only; placenta, breast milk, rabies vaccine; short lived