Lymphatic System 2004

Refer to chapter 14 in your text for additional help

Organs of Lymphatic System

Lymph vessels Lymph nodes Thymus Tonsils Spleen

Lymph

Specialized fluid formed in tissue spaces

Formed from blood plasma - or - interstitial fluid

Re-enters “circulation” via lymphatic capillaries

Lymph Vessels

Transports lymph back to circulatory system

Capillaries made of simple squamos epithelium = endothelium What is the importance of this?

LymphaticCapillaries → Lymphatic Venules

/veins → ↓

Terminal vessels:Right lymphatic duct -OR-Thoracic duct

←Circulatory veins

Lymph Transport

Lymphatic Vessels Definitions

Rt. Lymphatic duct & thoracic duct

Cisterna chyli

Lacteals

Lymph Nodes

Located in clusters along pathway of lymphatic vessels

Range in size from pinhead to lima bean

Most grouped in specific clusters Functions in defense and white blood

cell formation

Lymph Nodes Locale Clinically important

lymph nodes Submandibular Axillary Inguinal Popliteal

Lymph Node Defense

4 afferent lymph vessels carry lymph to nodes

Nodes filter particles Send back to circulatory system via 1

efferent lymph vessel

Thymus

Small lymphatic organ located in mediastinum

Source of lymphocytes before birth Helps in maturation of lymphocytes

(T-lymphocytes) Cells made under control of hormone

thymosin

Tonsils Clusters of lymphatic tissue located

in mucous membranes of mouth and throat

First line of defense from exterior environment

3 separate clusters: Palantine Pharyngeal Lingual

Tonsils continued

Spleen

Largest lymphatic organ Located in upper left quadrant Salvages iron and hemoglobin Acts as blood reservoir Filters blood

Bacteria Foreign substances Old RBC’s

Spleen Location

Function of lymphatic system

Aka immune system Made of molecules and cells Provides protection from:

Disease causing microorganisms Foreign tissue cells Malignant cells

Nonspecific immunity

Mechanisms that attack any irritant that threatens internal environment Skin Mucous membranes Tears

Inflammatory response

Part of nonspecific immunity Involves phagocytic WBC’s entering

affected area via: Increased blood flow Vascular permeability

Specific Immunity

Very specific protective mechanism against certain bacteria or toxins

Involves memory and recognition skills

Inborn or acquired immunity Natural immunity (passive or active)

Artificial immunity Active or passive