Lymphatic VesselsLymphatic Vessels

Carry lymph away from tissuesCarry lymph away from tissues Lymphatic capillariesLymphatic capillaries

More permeable than blood capillariesMore permeable than blood capillaries Epithelium functions as series of one-way valvesEpithelium functions as series of one-way valves

Lymphatic SystemLymphatic System

LymphLymph Lymphatic vesselsLymphatic vessels Lymphatic tissueLymphatic tissue Lymphatic nodulesLymphatic nodules Lymph nodesLymph nodes TonsilsTonsils SpleenSpleen ThymusThymus

Lymphatic System and Lymphatic System and Immunity:Immunity:

Functions of the Functions of the Lymphatic SystemLymphatic System

Fluid balanceFluid balance Excess interstitial fluid enters Excess interstitial fluid enters

lymphatic capillaries and becomes lymphatic capillaries and becomes lymphlymph

Fat absorptionFat absorption Absorption of fat and other Absorption of fat and other

substances from digestive tractsubstances from digestive tract DefenseDefense

Microorganisms and other foreign Microorganisms and other foreign substances are filtered from lymph by substances are filtered from lymph by lymph nodes and from blood by spleenlymph nodes and from blood by spleen

Lymphatic VesselsLymphatic Vessels Lymphatic capillaries join to formLymphatic capillaries join to form Lymphatic vesselsLymphatic vessels

Have valves that ensure one-way flowHave valves that ensure one-way flow Lymph nodes: Distributed along Lymph nodes: Distributed along

vessels and filter lymphvessels and filter lymph Lymphatic trunks: Jugular, Lymphatic trunks: Jugular,

subclavian, bronchomediastinal, subclavian, bronchomediastinal, intestinal, lumbar intestinal, lumbar

Lymphatic ducts: Right and thoracic Lymphatic ducts: Right and thoracic which connect to large veins which connect to large veins

Lymph Drainage Into Lymph Drainage Into VeinsVeins

Lymphatic Tissue and Lymphatic Tissue and NodulesNodules

Lymphatic tissueLymphatic tissue Consists mainly of Consists mainly of

lymphocyteslymphocytes Encapsulated or notEncapsulated or not

Lymphatic nodulesLymphatic nodules Numerous in loose Numerous in loose

connective tissue of connective tissue of digestive (Peyer’s digestive (Peyer’s patches), patches), respiratory, urinary, respiratory, urinary, reproductive reproductive systemssystems

TonsilsTonsils

Large groups of Large groups of lymphatic nodules in lymphatic nodules in nasopharynx and oral nasopharynx and oral cavitycavity

Provide protection Provide protection against bacteria and against bacteria and other harmful materialother harmful material

GroupsGroups PalatinePalatine PharyngealPharyngeal LingualLingual

Lymph NodesLymph Nodes

Organized in cortex and medullaOrganized in cortex and medulla Substances removed by phagocytosis or Substances removed by phagocytosis or

stimulate lymphocytes or bothstimulate lymphocytes or both Only structures to filter lymphOnly structures to filter lymph

Afferent and efferent vesselsAfferent and efferent vessels

SpleenSpleen Located in left superior side of abdomenLocated in left superior side of abdomen

Can be ruptured in traumatic abdominal Can be ruptured in traumatic abdominal injuries resulting in bleeding, shock, deathinjuries resulting in bleeding, shock, death

Blood flows through at 3 different ratesBlood flows through at 3 different rates Fast (most), slow, intermediateFast (most), slow, intermediate

FunctionsFunctions Destroys defective RBCsDestroys defective RBCs Detects and responds to foreign substancesDetects and responds to foreign substances Limited reservoir for bloodLimited reservoir for blood

SpleenSpleen

ThymusThymus

Located in superior mediastinumLocated in superior mediastinum Divisions: Cortex and medullaDivisions: Cortex and medulla Site of maturation of T cellsSite of maturation of T cells

ImmunityImmunity Ability to resist damage from foreign Ability to resist damage from foreign

substances as microorganisms and harmful substances as microorganisms and harmful chemicalschemicals

CategoriesCategories Innate or nonspecific resistanceInnate or nonspecific resistance

Mechanical mechanisms: Prevent entry or remove microbesMechanical mechanisms: Prevent entry or remove microbes Chemical mediators: Promote phagocytosis and Chemical mediators: Promote phagocytosis and

inflammationinflammation Cells: Involved in phagocytosis and production of chemicals Cells: Involved in phagocytosis and production of chemicals

Adaptive or specific immunityAdaptive or specific immunity Specificity: Ability to recognize a particular substanceSpecificity: Ability to recognize a particular substance Memory: Ability to remember previous encounters with a Memory: Ability to remember previous encounters with a

particular substance and respond rapidlyparticular substance and respond rapidly

Innate Immunity: CellsInnate Immunity: Cells White blood cellsWhite blood cells

Most important Most important cellular cellular components of components of immune systemimmune system

MethodsMethods ChemotaxisChemotaxis Phagocytosis Phagocytosis

NeutrophilsNeutrophils Phagocytic and Phagocytic and

first cells to enter first cells to enter infected tissueinfected tissue

MacrophagesMacrophages Monocytes that leave Monocytes that leave

blood, enter tissuesblood, enter tissues Large phagocytic cellsLarge phagocytic cells

Basophils and mast Basophils and mast cellscells Promote inflammationPromote inflammation

EosinophilsEosinophils Reduce inflammationReduce inflammation

Natural killer cellsNatural killer cells Lyse tumor and virus-Lyse tumor and virus-

infected cellsinfected cells

Inflammatory ResponseInflammatory Response

Tissue injury regardless of type can cause Tissue injury regardless of type can cause inflammationinflammation

Response initiated by chemical mediators Response initiated by chemical mediators that produce vasodilation, chemotactic that produce vasodilation, chemotactic attraction, increased vascular attraction, increased vascular permeabilitypermeability

TypesTypes Local: Symptoms are redness, heat, swelling, Local: Symptoms are redness, heat, swelling,

pain, loss of functionpain, loss of function Systemic: Symptoms are increase in Systemic: Symptoms are increase in

neutrophil numbers, fever and shockneutrophil numbers, fever and shock

Inflammatory ResponseInflammatory Response