Physiology Unit 3: Lecture 15: The Lymphatic System and Immunnity

what are the 3 main functions of the lymph system?

fluid balance, lipid absorption, defense

define fluid balance of the lymph system

excess interstitial fluid enters lymphatic capillaries and become lymph

define lipid absorption of the lymph system

absorption of fat and other substances from digestive tract via lacteals. lymph fluid is called chyle

define defense of the lymph system

microorganisms and other foreign substances are filtered from lymph, by lymph nodes and from blood by spleen

lymphatic capillaries and vessels remove ______

excessive fluid from tissues forming lymph, a clear fluid

lymph nodes filter _____ and are sites where _______.

lymph
lymphocytes respond to infections

where are lacteals located? and what they absorp?

small intestine and absorb lipids forming chyle

what is chyle

lymph containing lipids

before entering the blood, lymph from the body passes through the

thoracic duct or right lymphatic trunks

the spleen filters _____ and is a site where ____

blood
lymphocytes respond to infections

where do lymphocytes originate

stem cells in the bone marrow

pre-B cells (lymphocytes) become what?

mature B cells in red bone marrow

pre-B cells (lymphocytes) are released where?

into the blood

pre-B=T cells (lymphocytes) enter where?

blood and migrate to the thymus

what do pre T cells do in the thymus?

increase in number and become mature T cells

where are T cells released

into the blood

B cells and T Cells from the blood enter and do what?

populate lymphatic tissues

where can lymphocytes remain in the body?

in tissues or pass through tissues and return to the blood to respond to infections

define immunity

the ability to resist damage from foreign substances such as microorganisms and harmful chemicals

what are the two categories of immunity

innate and adaptive

define innate immunity

body defenses that are present at birth and generically determined

list physical barriers of innate immunity

skin, mucous membranes, tears, saliva, cillia in respiratory tract, coughing

describe surface chemicals

lysozymes, lyse cells, acid secretions, that prevent microbial growth or kill microorganisms. mucus on the mucous membranes traps microorganisms until they can be destroyed

describe complement

group of 20 proteins that circulate in blood in inactive form that become activated through complement cascade

where does the alternative pathway of a complement start?

C3

where does the classical pathway of a complement begin

C1

activated C3-C7 promote what?

phagocytosis, inflammation, and chemotaxis

activatied C5-C9 combine to form what?

membrane attack complex (MAC)

activated complement proteins can

form MAC, opsonization, attract immune system cells and promote inflammation

define opsonization

complement proteins attach to surface of bacterial cells to stimulate phagocytosis

define interferons

proteins that protect against viral infections and some forms of cancer

define infection

viruses enter host cells and use the host cell's protein-making organelles to make and assemble new viruses that are released to infect other cells

virus infected cells produce ____ and stimulate ______

interferons
stimulate them to produce antiviral proteins that will then stop viral replication in neighboring cells

the inflammatory response is always what kind of injury?

tissue injury

within the inflammatory response the response initiated by chemical mediators produces what?

vasodilation

what are the types of inflammatory responses?

local inflammation and systemic inflammation

define and give symptoms for local inflammation

confined to a specific area of the body. symptoms include redness, heat, swelling, pain, loss of function

define and give symptoms for systemic inflammation

occurs in many parts of the body. same symptoms as local, but additionally increases neutrophil numbers, fever, widespread increased vascular permeability

define adaptive immunity

involves the ability to recognize, respond to, and remember a particular substance

what are stimulants of adaptive immunity

antigens
foreign
self antigens

what is an antigen?

large molecules that float on or around a cell's surface

what is a foreign stimulant?

not produced body, from the outside and forms an attack

what is a self-antigen?

produced by body. used as markers to allow adaptive immune response to differentiate self from non-self

what are the types of adaptive immunity

antibody mediated
cell mediated
cytoxic t cells
helper T cells
regulatory T cells

function of antibody mediated antigens

B cells give rise to antibodies

cell mediated immunity is what kind of cells

T cells

cytoxic T cells do what?

destroy infected cells

Helper T cells and recularory t cells do what

promote or inhibit both antibody-mediated and cell mediated immunity

for an adaptive immunity response to occur, what must a lymphocyte do

interact and recognize an antigen

what region of antigens do lymphocytes interact with

antigenic determinants

lymphocytes have identical _____ on their surfaces that combine with a specific antigenic derterminant of a given antigen. this is similar to what?

antigen receptors
lock and key model

describe B-cell antigen receptors

four polypeptide chains, two identical variable regions

describe T cell antigen receptors

two polypeptide chains divided into variable and constant regions

what must immune cells be able to distinguish

the difference between self-antigens and foreign antigens, and if a self cell cells has been compromised by an infection or mutation

most lymphocyte activation involves surface proteins called

major histocompability complex (MHC) molecules

what are the two types of MHC molecules

MHC class I
MHC class II

what is the first step in MHC Class I molecule and endrogenous antigen process?

when a virus reproduces inside a cell, viral proteins are produced within the cell

after a virus reproduces inside a cell, viral proteins are produced within the cell. what is the second step in MHC Class I molecule and endrogenous antigen process?

some of the viral proteins are broken down into the cytoplasm

after some of the viral proteins are broken down into the cytoplasm. what is the third step in MHC Class I molecule and endrogenous antigen process?

the protein fragments enter the rough ER and combine with MHC class I molecules to form complexes

after the protein fragments enter the rough ER and combine with MHC class I molecules to form complexes. what is the fourth step in MHC Class I molecule and endrogenous antigen process?

the MHC class I / antigen complex then move through the golgi apparatus to be further transported to the plasma membrane

after the MHC class I / antigen complex then move through the golgi apparatus to be further transported to the plasma membrane. what is the fifth step in the MHC class I molecule and endrogenous antigen process?

MHC class I / antigen complexes on the cell's plasma membrane can bind to T cell receprots on the surface of T cells. this combination is a signal that activates T cells. activated t cells can destroy infected cells, which effectively stops viral replication.

what is the first step of the MHC class II molecules and exogenous antigens?

antigen - presenting cells can take in foreign antigens by endocytosis

after antigen - presenting cells can take in foreign antigens by endocytosis. what is the second step of the MHC class II molecules and exogenous antigens?

within the endocytotic vesicle, the antigen is broken down into fragments to form processed antigens

after, the antigen is broken down into fragments to form processed antigens. what is the third step of the MHC class II molecules and exogenous antigens?

Vesicles from the golgi apparatus containing MHC class II molecules combine with the endocytotic vesicles. the MCH class II molecules and processed antigens combine

after Vesicles from the golgi apparatus containing MHC class II molecules combine with the endocytotic vesicles. the MCH class II molecules and processed antigens combine. what is the fourth step of the MHC class II molecules and exogenous antigens?

The MCC class II antigen complexes are transported to the plasma membrane, where they are displayed to other immune cells.

after the MCC class II antigen complexes are transported to the plasma membrane, where they are displayed to other immune cells. what is the fifth step of the MHC class II molecules and exogenous antigens?

the displayed MHC class II antigen complex can stimulate immune cells

what is clonal selection

the mechanism that results in a large population of identical lymphocytes called clones

how does clonal selection occur?

when a lymphocyte proliferates and differentiates when exposed to a specific antigen

postitive selection

ensures survival of lymphocytes that react against antigens. these then proliferate and form clones

negative selection

elimination of clones of lymphocytes that react against self antigens

what is costimulation?

the binding of the MHC class II / antigen complex to the T cell receptor

what is lymphocyte proliferation?

cells from original clones must proliferate before antigen can be attacked effectively

proliferation of what cell occurs first?

helper T cells

in lymphocyte proliferation helper T cells aid in

proliferation and activation of B cells or cytotoxiv T cells

in lymphocyte proliferation B cell activation results in

plasma cells and memory B cells

define tolerance

state of unresponsiveness of lymphocytes to a specific antigen.

in tolerance, unresponsiveness is the most important to what?

self anticens

tolerance is induced by

deletion of self reactive lymphocytes
preventing activation of lymphocytes that encounter self antigens
activating of regulatory T cells that may kill antigen presenting cells

antibody mediated immunity involves the production of what

antibodies in response to extracellular antigens

exposure to antigens can lead to activation of

B cells

the production of antibodies ______ the antigen

destroys

antibodies are effected against

extracellular antigens

antibodies are _____

proteins produced by B cells taht became plasma in response to an antigen

what is the first step in the proliferation of B cells?

antigen binds to B cell receptor and both the receptor and antigen are taken into the cell

after an antigen binds to B cell receptor and both the receptor and antigen are taken into the cell. what is the second step of proliferation of B cells?

The B cell uses an MHC II molecule to present the processed antigen to the helper T cell

after The B cell uses an MHC II molecule to present the processed antigen to the helper T cell. what is the third step of proliferation of B cells?

costimulation of the B cell occurs through surface molecules

after costimulation of the B cell occurs through surface molecules. what is the fourth step of proliferation of B cells?

B cells divides, and the resulting daughter B cells divide and so on producing many B cells that recognize the same antigen

after the B cells divides, and the resulting daughter B cells divide and so on producing many B cells that recognize the same antigen. what is the fifth step of proliferation of B cell?

many of the daughter cells differentiate to become plasma cells which produce antibodies. antibodies are part of the immune response that eliminates the antigen.

after many of the daughter cells differentiate to become plasma cells which produce antibodies. antibodies are part of the immune response that eliminates the antigen. what is the 6th step of proliferation of B cells?

daughter cells that do not differentiate to become plasma cells reduce in size and become memory B cells. memory B cells may become active in future encounters with the same antigen

what can antibodies bind to?

single or several antigenic determinant and interfere with the antigen's ability to function

primary response of antibody production occurs when

B cell is first activated by its specific antigen.

how long does a primary response take to form

normally 3-14 days

what symptoms are developed during a primary response?

the symptoms of the disease generally develop

when does a secondary response of antibody production occur

when another exposure to the same antigen causes the memory cells to rapidly form plasma cells and additional memory cells.

in comparison to a primary response how long does a secondary response take to form?

faster and produces more antibodies than the primary response

sympotms formed from the secondary response

none. typically the person does not get sick

define cell mediated immunity

an adaptive immune response that is independent of antibodies but involves immune cells that specifically recognize, target and clear infected host cells

when is cell mediated immunity the most effective?

cytoplasmic microbes through the action of cytotozis cells responding to endogenous antigens

what are the two major ways in which cytotoxic T cells function?

forming a hole in the plasma membrane of the target cell
producing cytokines to promote phagocytosis and inflammation

what is the process of proliferation of cytotoxic T cells

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