Lecture OverviewLecture Overview

Lymphatic System and Components– What is lymph and how does it travel?

General Immune Reaction- Inflammation– What is one function of the cells carried in

lymph?

Selected Topics in Immunity

Lymphatic SystemLymphatic System

Absorbs excess fluid from the tissues

Returns this fluid to the circulatory system or the heart

Additional function in Immunity

Components of the Lymphatic Components of the Lymphatic SystemSystem

LymphLymphatic TissueLymphatic VesselsThymusBone MarrowSpleen

LymphLymph

Lymph– The clear fluid

absorbed by the lymphatic system

Lymphatic Tissue– Clusters of

Lymphocytes and macrophages

Lymphatic TissueLymphatic Tissue

Malt: (Mucosa Associated Lymphatic Tissue) – Diffuse array of lymphocytes found along body

passages in mucous membranes.– Examples of malt: lining of the stomach and

respiratory tract

Lymph nodules: – Dense clusters of Lymphocytes – Transient: pop up during infection

Lymphatic VesselsLymphatic Vessels Carry and Transport

Lymph and proteins

Similar Structure to veins– Tunica Interna: Thin

inner lining and valves– Tunica Media: Elastic

fibers and Smooth Muscle

– Tunica Externa: Thin Outer Layer

Lymphatic FiltersLymphatic Filters

Lymph Nodes- Screen and Filter Lymph for infectious particles

Spleen- Screen and Filter Blood for old, dead cells and infectious particles

Subclavian

2 collecting Trunks

6 Lymphatic Trunks

More Collecting Vessels

Lymph Nodes

Collecting Vessels

Lymphatic Vessels

Lymphatic MovementLymphatic Movement

No pump

Rhythmic contraction of the lymph vessels

Skeletal Muscles

How is backflow prevented?

Immune Cell GeneratorsImmune Cell Generators

Bone Marrow- Makes B- Cells

Thymus- Makes T- Cells

ThymusThymus

Break for Dynamic Human

InflammationInflammation

Non-specific response to tissue trauma or infection

44 signs of Inflammation signs of Inflammation

44 signs of Inflammation signs of Inflammation

RednessSwellingHeatPain

What’s the purpose of pain?

Purpose of InflammationPurpose of Inflammation

Remove Invading Pathogens

Remove Debris of Damaged Tissues

Initiate Tissue Repair

Mediators of InflammationMediators of Inflammation

Chemical Messengers

Leukocyte

Chemical MessengersChemical Messengers

Released by mast cells in response to damage

Bradykinin, Histamine, and Leukotrienes– Increases Local Blood Flow to distressed area

Stimulates Vasodilation Increases Permeability of Capillaries

What’s Accomplished?

Chemical MessengersChemical Messengers

Bradykinin, Histamine, and Leukotrienes– Increases Local Blood Flow

Stimulates Vasodilation Increases Permeability of Capillaries

What’s Accomplished?– Heats area causes redness and swelling– Dilutes toxins and helps Remove waste– Supplies oxygen and nutrients for tissue repair

Pain ResponsePain Response

Purpose?

Causes?

Pain ResponsePain Response

Purpose? Prevents further injury to area.

Causes?– Direct Nerve Damage– Pressure from Swelling– Chemical Stimulation particularly bradykinin

Leukocyte DeploymentLeukocyte Deployment

Leukocyte: any white blood cell including T cells, B cells, granulocytes, platelets, basophils, mast cells, monocytes and macrophages

Leukocytes Migrate toward inflammed area

Why? TO KILL and RECRUIT

Leukocyte DeploymentLeukocyte DeploymentLeukocytes Migrate to inflammed tissue

How? 1. Margination or pavementing: To migrate to the wall of a capillary

2. Diapedesis: Passage of blood cells through vessel wall into tissue 3. Chemotaxis: Movement of a cell towards or away a chemical source

What do the leukocytes plan What do the leukocytes plan to do?to do?

Phagocytosis: release of toxic chemicals

Recruit more leukocytes

PhagocytosisPhagocytosis

Leukocytes consume and destroy foreign invaders and dead cells

Ejected as Pus

Break for Break for Dynamic HumanDynamic Human

Selected Topics in ImmunitySelected Topics in Immunity