Lymphatic System

1
Lymphatic System

• Lymphatic System Definition
• 1. Returns leaked plasma to the blood vessels
  after cleansing it of bacteria other
  foreign matter.
• 2. Provides sites for surveillance by immune
  cells.
• TWO PARTS of the LYMPHATIC SYSTEM
• 1. Lymphatic Vessels
• 2. Lymphoid Tissues Organs
• LYMPHATIC VESSELS
• Function To pick up excess tissue fluid called
  LYMPH that leaked from blood vessels and return
  it to the blood stream.
• LYMPH is composed mostly of H20 with a small amt
  of dissolved proteins
• Description of Vessels Thin walled with valves
  forms ONE way flow toward the HEART ONLY. Low
  pressure PUMPLESS system.

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Lymphatic System

• Draining of LYMPH p. 370 371
• RIGHT LYMPHATIC DUCT Drains Lymph from the right
  side of the head and thorax.
• THORACIC DUCT Receives Lymph from the rest of
  the body. BOTH ducts empty lymph into the
  Subclavian Veins on their side.
• Transportation of LYMPH (3 modes)
• Milking action of skeletal muscles
• Pressure changes in the thorax during breathing
• Rhythmic contractions of smooth muscles in walls
  of the vessels
• LYMPH NODES Function
• Protect the body by removing foreign material
  such as tumor cells from the lymphatic system and
  by producing lymphocytes.

3
Lymphatic System

• LYMPHATIC ORGANS ( 4 Types)
• Tonsils, Thymus Gland, Spleen, Peyers
  Patches(Small Intestines)
• Functs. House phagocytes and lymphocytes which
  help in the bodys defense and resistance to
  disease
• Primary sites of LYMPH NODES ( 3 areas)
• Inguinal (Groin)
• Axillary ( Armpit)
• Cervical ( Neck)
• What TWO things found in the LYMPH NODES help
  engulf and destroy bacteria and viruses BEFORE
  they return to the blood?
• Macrophages
• Lymphocytes

4
Lymphatic System

• What causes swollen glands during an infection?
• Trapping of bacteria and viruses by the lymph
  nodes
• LYMPH Nodes can become SECONDARY sites for CANCER
• LYMPH Nodes that are swollen but NOT painful can
  be diagnosed as CANCEROUS.
• What is the SIZE of lymph nodes?
• Most are kidney shaped, less than 1 inch long and
  buried in the connective tissue that surrounds
  them.

5
Lymphatic System

• Other Types of LYMPHOID ORGANS
• SPLEEN(Red Blood Cell Graveyard)
• Location Left side of abdominal cavity curls
  around front of stomach.
• Function 1. Filters and cleanses blood of
  bacteria viruses
• 2. Destroys worn out RBCs and returns some of
  the breakdown products to the liver
• 3. Stores platelets and acts as a blood reservoir
• THYMUS
• Location Low in the throat overlying the heart
• Function Produces hormones (Thymosin) that
  program certain lymphocytes.

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Lymphatic System

• LYMPHOID ORGANS contd
• 3. TONSILS
• Location Pharnyx (Throat)
• Function Trap and remove bacteria or other
  foreign pathogens entering the throat.
• 4. PEYERS PATCHES
• Location Walls of the Small Intestine
• Function Capture and destroy bacteria that are
  trying to enter the intestines