Lymphatic System

Interstitial Fluid

where the lymphatic system is

the immune system

intricate collection of cells and organs that destroy or neutralize pathogens

the lymphatic system

associated with immune system

example of connection between immune and lymphatic system

swelling of lymph nodes during infection

lymphatic system returns

fluids leaked from blood vessels back to blood

lymphatic system consists of three parts

network of lymphatic vessels, lymph fluid in vessels, lymph nodes that cleanse lymph

lymphoid organs and tissues

provide structural basis of immune system by housing phagocytic cells and lymphocytes

lymphoid organs and tissues are

spleen, thymus, tonsils, lymph nodes, other lymphoid tissues

lymphatic vessels

elaborate network of drainage vessels

lymphatic system is similar

to veins

ends of lymphatic vessels are

open to tissue space

lymphatic vessels offer

a one way system ensuring lymph only flows toward heart

no pump so lymphatic vessels rely on

lymphatic system and movements of body like muscle contraction, one way valves, diaphragmatic breathing

lymphatic capillaries can take up

larger molecules and particles that blood capillaries cannot

because of this they can act as a route for

pathogens or cancer cells to travel throughout the body

lymphatic capillaries are

blind ended vessels that weave between tissue cells and blood capillaries

lymphatic capillaries are similar

to blood capillaries but more permeable

the increased permeability in lymphatic capillaries are due to two specialized structures

endothelial cells overlapping creating mini valves,

lymph capillaries drain into

increasingly larger vessels called collecting lymphatic vessels

large lymphatic vessels consist of

vessels trunks and ducts

large lymphatic vessels have structures and tunics

similar to veins

lymphatic trunks are formed by

union of largest collecting vessels, drain large areas of body

lymph is delivered from

from trunks into one of two large lymphatic ducts

two large lymphatic ducts

right lymphatic duct and thoracic duct

right lymphatic duct

drains right upper arm and right side of head and thorax

thoracic duct

drains rest of body

each of these ducts empties

lymph into venous circulation at junction of internal jugular and subclavian veins on its own side of body

lymph transport system is a low

pressure system like venous system

lymph is propelled by same mechanisms like

milking action of skeletal muscles, pressure changes, valves preventing backflow, contraction of smooth muscle in walls of lymphatics

physical activity increases

flow of lymph

lymphedema

severe localized edema

lymphedema cause

anything that prevents normal return of lymph to blood

lymphedema causes examples

tumors blocking lymphatics or removal of lymphatics during cancer surgery

barrier defenses

prevent pathogenic invasion into the body tissue; skin, mucous membranes

innate immune response

rapid but non specific; variety of specialized cells and soluble factors

adaptive immune response

many cell types; primarily controlled by wbcs known as lymphocytes

main functions of lymphoid tissues

houses and provides proliferation sites for lymphocytes and offers surveillance vantage points for lymphocytes and macrophages as they filter through lymph

lymphoid tissue is largely composed of

reticular connective tissue

macrophages live on

reticular fibers

spaces between fibers off a place for

lymphocytes to occupy when they return from patrolling body

lymphoid organs

are grouped into two functional categories

primary lymphoid organs

where lymphocytes mature

secondary lymphoid organs

house here; where lymphocytes go after they mature

lymph nodes

tons throughout the body

two main functions of lymph nodes

cleansing lymph and immune system activation

cleansing the lymph

act as lymph filter; macrophage remove and destroy microorganisms and debris; prevents unwanted substances from getting into blood

immune system activation

offer a place for lymphocytes to become activated and mount an attack against antigents

structure of lymph node: cortex

outside superficial area that contains follicles

structure of lymph node: afferent lymphatic vessels

fluid flowing in

structure of lymph node: efferent lymphatic vessels

fluid leaving

structure of lymph node: medulla

inside area

structure of lymph node: lymph sinuses

openings; found throughout the node

circulation in lymph nodes

lymph enters afferent lymphatic vessels, travels through subscapular sinus (smaller sinuses found throughout cortex and medulla), finally exits efferent lymphatic vessels

why are there more afferent?

to slow down and give chance to catch things/destroy

buboes

inflamed swollen tender lymph nodes that result when nodes are overwhelmed by what they are trying to destroy

condition often referred to as swollen glands

not glands

buboes are sometimes pus filled

wbc/neutrophils

lymph nodes can become

secondary cancer sites if metastasizing cancer cells become trapped in node

difference in presentation lymph nodes

pain = im sick, pathogen, bacteria, vireus; chronically swollen not painful = cancer

spleen

blood rich organ, screens for RBC, largest lymphoid organ; splenic artery and vein

spleen functions

houses lots of lymphocytes; cleanses blood of aged blood cells and plateletes

mono

enlarged spleen

three additional functions of spleen

stores breakdown products of RBCs for later use; stores blood platelets and monocytes for release into blood when needed; may be site for fetal erythrocyte production

spleen": white pulp

site where immune function occurs; contains most lymphocytes on reticular fibers

spleen: red pulp

site where old blood cells and bloodborne pathogens are destroyed; rich in RBCs and macrophages

can live without spleen but immune system

is diminished

splenectomy

surgical removal of ruptured spleen

if spleen must be removed

liver and bone marrow take over most of its function

athletes cant play with mono

spleen can rupture

malt

mucosa associated lymphoid tissue

malt located

anything that has opening to outside has mucous

tonsils

simplest lymphoid organs

tonsils function

gather and remove pathogens in food or air

peyers patches

clusters of lymphoid follicles in wall of distal portion of small intestines

peyers patches function

destroy bacteria preventing them from breaching intestinal wall

appendix

offshoot of first part of large intestines

now appenidx treatment

can be treated with antibiotic but doesnt start working for 24 hours

thymus

bilobed lymphoid organs organ found in inferior neck

thymus function

t cells mature; active and largest in childhood

hodgkins lymphoma

malignant lymphoid tissue; symptoms are swollen non painful lymph nodes, fatigue, fever and night sweats; malignantly transformed b cells called reed sternberg cells; responds well to chemo

non hodgkins lymphoma

includes all cancers of lymphoid tissue except hodkins; uncontrolled metastasis of undifferentiated lymphocytes; swollen lymph nodes, spleen, peyer patches; clinically agreessive; often responds to chemo if not is fatal

sentinel node

first node to receive lymph drainage, therefore examined for presence of cancer cells

breast cancer

check axillary region to make sure its not in lymph node