Lecture 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 System

Absorbs excess fluid from the tissuesReturns this fluid to the circulatory system or the heart

Additional function in Immunity

Components of the Lymphatic System

Lymph Lymphatic Tissue Lymphatic Vessels Thymus Bone Marrow Spleen

Lymph Lymph Lymphatic

The clear fluid

absorbed by the lymphatic system

Tissue Clusters of Lymphocytes and macrophages

Lymphatic 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 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 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 Movement

No pumpRhythmic contraction of the lymph vessels Skeletal Muscles How is backflow prevented?

Immune Cell Generators

Bone Marrow- Makes B- Cells

Thymus- Makes T- Cells

Thymus

Break for Dynamic Human

Inflammation

Non-specific response to tissue trauma or infection

4 signs of Inflammation

4 signs of Inflammation

Redness Swelling Heat Pain

Whats the purpose of pain?

Purpose of Inflammation

Remove Invading PathogensRemove Debris of Damaged Tissues Initiate Tissue Repair

Mediators of Inflammation

Chemical Messengers

Leukocyte

Chemical Messengers

Released by mast cells in response to damageBradykinin, Histamine, and Leukotrienes Increases Local Blood Flow to distressed area

Stimulates Vasodilation Increases Permeability of Capillaries

Whats Accomplished?

Chemical Messengers

Bradykinin, Histamine, and Leukotrienes Increases Local Blood Flow Stimulates Vasodilation Increases Permeability of Capillaries

Whats Accomplished? Heats area causes redness and swelling

Dilutes toxins and helps Remove waste Supplies oxygen and nutrients for tissue repair

Pain Response

Purpose?Causes?

Pain Response

Purpose? Prevents further injury to area.Causes? Direct Nerve Damage Pressure from Swelling Chemical Stimulation particularly bradykinin

Leukocyte Deployment

Leukocyte: any white blood cell including T cells, B cells, granulocytes, platelets, basophils, mast cells, monocytes and macrophagesLeukocytes Migrate toward inflammed area Why? TO KILL and RECRUIT

Leukocyte Deployment

Leukocytes 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 to do?

Phagocytosis: release of toxic chemicals Recruit more leukocytes

Phagocytosis

Leukocytes consume and destroy foreign invaders and dead cellsEjected as Pus

Break for Dynamic Human

Selected Topics in Immunity