nurs 210: chapter 20 & 21 - lympathic system & lymphoid organs & tissues

nonspecific resistance (innate immunity)

present at birthday ad includes defense mechanisms that provide general protection against invasion by wide range of pathogens

immunity (adaptive immunity)

involves activation of specific lymphocytes that combat a particular pathogen or other foreign substance

lymphatic system

body system that carries out immune responses

components of lymphatic system

consists of several structures and organs that contain lymphatic tissue, bone marrow, a fluid called lymph that flows within lymphatic vessel

lymphatic system functions:

to drain interstitial fluid, transport dietary fats, carry out immune response

lymphatic vessels

begin as lymphatic capillaries, which are closed on one end; lymphatic capillaries are located between cells of many tissues, merge to form lymphatic vessels, which have thin walls and many valves

picture of lymphatic capillaries

from the lymphatic vessels, lymph passes through:

the lymph nodes and then into lymph trunks; the lymph trunks then merge to form either the thoracic duct or the right lymphatic duct

thoracic duct drains:

lymph from both lower limbs, abdomen, left side of chest, left arm, left side of head and neck

right side of upper body is drained by:

right lymphatic duct

picture of routes of drainage

formation and flow of lymph

interstitial fluid → lymph capillaries → lymph vessels → lymph trunks → lymph ducts → subclavian veins

primary lymphatic organs are:

organs where immune cells become immunocompetent; red bone marrow, thymus

secondary lymphatic organs and tissues include:

lymph nodes, spleen, lymphatic nodules

lymph nodes

principal secondary lymphoid organs of body, hundreds of nodes are found throughout body

two main functions of lymph nodes

cleansing the lymph, immune system activation

cleansing the lymph

act as lymph “filters”; phagocytes remove and destroy microorganisms and debris that enter lymph, prevent unwanted substances from being delivered to blood

immune system activation

site for lymphocytes to become activated and mount an attack against antigens

lymph nodes

spleen

a blood-rich organ about size of fist, located in left side of abdominal cavity, below stomach; largest lymphoid organ

function of spleen

site of lymphocyte proliferation and immune surveillance and response, cleanses blood of aged blood cells and platelets; macrophages remove debris

spleen has a thin capsule, so dircet blow or severe infection may cause:

it to rupture, spilling blood into peritoneal cavity

picture of spleen

lymphatic nodules are:

masses of lymphatic tissue that are not surrounded by a capsule

lymphatic nodules are scarttered throughout:

the lamina propria of mucous membranes linign the gastrointestinal, urinary, and reproductive tracts and respiratory airways

lymphatic nodules in these areas are also referred to:

as mucosa-associated lymphatic tissue (MALT); tonsils, peyer’s patches, appendix

innate immunity

a wide variety of body responses that serve to protect against invasion of a wide variety of pathogens and their toxins; it’s present at birth and has two lines of defense

two lines of defense for innate immunity

skin and mucous membranes (first line), internal defenses (second line)

skin and mucous membranes defenses

mechanical defenses, chemical defenses

mechanical defenses for skin and mucous membranes

skin mucous membranes, tears, saliva, mucus, cilia, epiglottis, urine flow, defecating, vomiting

chemical defenses for skin and mucous membranes

sebum, lysozyme, gastric juice

internal defenses

antimicrobial proteins, phagocytes, nautral killer cells, inflammation, fever

picture of internal defenses: phagocytes, inflammation

adaptive immunity

the body’s ability to defend itself against specific invading agents; antigens are substances recognized as foreign that provoke immune responses

adaptive memory is the third line of defense, which has both:

specificity and memory

adaptive community is divided into two types:

cell-mediated: T-lymphocyte activation; antibody-mediated: B-lymphocyte activation

B cells (lymphocyte)

mature in bone marrow

T cells (lymphocyte)

mature in thymus

types of T cells

helper T cells (CD4), cytotoxic T cells (CD8), memory T cells

helper T cells (CD4)

activate other immune cells (CD8 and B cells)

cytotoxic T cells (CD8)

kill infected or abnormal cells (cell-mediated immunity)

B cells multiply to form:

plasma cells produce antibodies: bind and neutralize pathogens (antibody-mediated immunity); memory B cells

antigen

substance that triggers an immune response in body

reactivity

ability of an antigen to bind to specific immune molecules

immunogenicity

ability of an antigen to trigger an immune responses

just certain small parts of a large antigen molecule act as:

triggers for immune responses; small parts are called epitopes

antibodies (immunoglobulins) produced by:

plasma cells (B cells become plasma cells) to identify and neutralize foreign antigens

IgG

most common in blood, produced during secondary immune responses

IgM

first to increase, produced during the primary immune responses

IgA

present in secretions (tears, saliva, breast milk)

IgE

responsible for allergic response

IgD

binds to activate B cells

picture of table classes of immunoglobulins

antibodies

adaptive immunity can be classified based on:

how it is acquired into four types: natural, artificial, active, passive

natural, adaptive (acquired) immunity

stimulated by an environment or a mother

artificial, adaptive (acquired) immunity

stimulated by a medical intervention

active, adaptive (acquired) immunity

person produces own antibodies; delayed protection that is permanent

passive, adaptive (acquired) immunity

person receives antibodies from outside source; instant protection that is temporary

natural active immunity

direct exposure to a pathogen stimulates immune system (B cells) to produce antibodies: strong primary immune response

natural passive immunity

baby receives antibodies through placenta or breast milk (protected for about 6-8 months after birth)

artificial active immunity

occur when vaccine is given, which stimulates B cells to produce antibodies

artificial passive immunity

ready antibodies are given; short term protection lasts until antibodies break down

picture of acquired immunity breakdown