Lymphatic System

B11-5-03 Explain the role of the lymphatic system in protecting the human body.

Include: lymph vessels, lymph nodes, and lymph

WARNING! WARNING! WARNING!

White blood cells are the same as …Lymphocytes, in which there are many types…Neutrophils, eosinophil's, basophils, monocytes which are perform…Phagocytosis!

Also B Lymphocytes = B Cells

• Key component of immune system• Like a secondary circulatory system– How does the circulatory system work?

• Functions to– Filter and destroy foreign substances– Filter and destroy cell debris – Produce lymphocytes

Organization

Lymph Vessels

• Begins with lymphatic capillaries– Take up excess fluid• Lymph

• Muscle contractions of vessels “squeeze” lymph along

• Prevented from flowing backward by one-way valves

Lymph

• Clear, colourless fluid collected as it filters through the capillaries of the blood

How does it work?

• Lymph passes from tiny capillaries to lymph vessels

• Flows through lymph nodes located along vessels

• Cells of the lymph nodes phagocytize (ingest) – Bacteria– Red blood cells– Cellular waste

How does it work? Cont…

• The lymph drains into either – Thoracic duct– Right lymphatic duct

• The lymph is then transported back into the veins of shoulder area

• Re-enters the general circulatory system

Where does it drain?

• Thoracic Duct– Below thorax– Left arm– Left side of head– Left side of neck

• Into the left subclavian vein

• Right Lymphatic Duct– Right arm– Right side of head– Right side of neck

• Into the right subclavian vein

Lymphatic Organs

Tissues of the Lymphatic System

• Contain large number of lymphocytes (WBC)– B-Cells– T-Cells

Red Bone Marrow

Red Bone Marrow

• Network of connective tissue fibres• Site of stem cells– Divide and produce lymphocytes

• B Lymphocytes mature

Thymus

Thymus

• Central organ control lymphocyte production and antibody formation

• Mature T lymphocytes from red bone marrow– Determines which T cells can detect antigens

Spleen

Spleen

• Filters the blood• Harbours lymphocytes that– Remove of and defective blood cells– Phagocytize foreign particles

Lymph Nodes

Lymph Nodes

• Small structures along lymphatic vessels, – cleanse lymph• Phagocytosis of foreign particles

Lymph Nodes

• During an Infection become enlarged with lymph, white blood cells, and can be felt

• Infections of the … can be felt …– Neck or head• In the neck

– Breast or arm• In the axillary region

– Pelvis or legs• In the inguinal region