The Lymphatic System and Fluid Transport

• The lymphatic system is a circulatory system that works closely with the cardiovascular system.

Lymphatic System Components

• Nutrients and wastes are exchanged between the blood and tissues as blood circulates.
• Fluid exits the bloodstream into extracellular space and is reabsorbed.
• Fluid not immediately returned contributes to interstitial fluid.
• Lymphatic system returns unabsorbed fluid to the bloodstream; this ensures enough blood volume is maintained.

Impacts of Impaired Lymphatic Drainage

• Welling (Edema): Fluid accumulation in tissues causes puffiness, especially in legs, arms, or face.
• Tissue Damage: Cells don't get enough oxygen/nutrients à poor healing and pain.
• Weakened Circulation: Reduced blood volume à harder for the heart to pump efficiently.
• Increased Risk of Infections: Waste and pathogens aren't removed and toxins/bacteria build up.

Interstitial Fluid Drainage into Lymphatic Capillaries

• Blood pressure forces fluid out of capillaries into spaces between cells (interstitial fluid).
• Lymphatic capillaries absorb the fluid.
• Lymphatic capillaries have flap-like valves that open when fluid pressure outside is higher
• Fluids, proteins and waste enters the lymphatic system

Lymph Filtration and Transportation

• Lymph travels through lymph nodes, which filter bacteria and debris.
• Lymph is eventually returned to the bloodstream through veins near the heart.
• Interstitial fluid in the lymphatic system is called lymph.

Lymph Node Clusters

• Cervical lymph nodes are in the neck and filter lymph from the head and neck.
• Axillary lymph nodes are in the armpits and filter lymph from the arms, chest, and breasts.
• Inguinal lymph nodes are in the groin and filter lymph from the legs and lower abdomen.

Lymphatic Ducts

• Right Lymphatic Duct drains lymph from the right side of the head, right arm, and right chest into the right subclavian vein.
• Thoracic Duct drains lymph from the rest of the body into the left subclavian vein.
• Lymphatic ducts empty into the subclavian veins of the venous system.
• Veins return the filtered lymph to the superior vena cava, which leads back to the heart.

Drainage Sequence

• Interstitial Fluid leaks from blood capillaries into tissues.
• Lymphatic Capillaries absorb excess fluid, turning it into lymph.
• Lymphatic Vessels transport lymph, which moves through larger vessels and lymph nodes for filtering.
• Larger Lymphatic Trunks are where multiple vessels merge.
  • Right lymphatic duct → Right subclavian vein
  • Thoracic duct → Left subclavian vein
• Subclavian Veins drain into the Superior Vena Cava, then the Heart à Lymph returns to the bloodstream and circulates again.

Lymphatic Fluid Movement

• Skeletal Muscle Contractions help squeeze lymphatic vessels during movement, pushing lymph forward toward larger vessels and ducts.
• Breathing Movements (Respiratory Pump) involve inhaling and exhaling to create pressure changes in the chest, drawing lymph from smaller vessels.
• Valves in Lymphatic Vessels prevent backflow, ensuring lymph moves correctly toward the heart.
• Smooth Muscle Contractions in Lymphatic Vessel Walls: Larger lymphatic vessels have smooth muscle that contracts rhythmically to keep lymph flowing.
• Body Position: Lying down or elevating legs can help lymph drain from lower limbs and changing positions encourages lymph movement.

Lymph Drainage Regions

• The green area on diagrams (right upper quadrant) drains into the Right Lymphatic Duct
  • Includes the right side of the head, right arm, and right chest
  • Lymph from this area enters the right subclavian vein
• The pink area on diagrams (remaining 3/4 of the body) drains into the Thoracic Duct
  • Includes the left side of the head, left arm, entire lower body, and abdomen
  • Lymph from this larger area enters the left subclavian vein

Mrs. Jean Page Case Study

• Mrs. Jean Page, 56, has cancer in the upper-right quadrant of her right breast.
• She had a lumpectomy and axillary resection of lymph nodes from the armpit 8 weeks prior.
• Her right arm is edematous, reddened, and painful, indicating possible cellulitis, and is getting bigger/more swollen.

Lymph Flow in Mrs. Page's Affected Arm

• Lymph Capillaries absorb excess fluid from tissues in the right arm.
• Lymphatic Vessels transport lymph through the arm toward the lymph nodes.
• Axillary Lymph Nodes (Right Armpit) filter lymph, removing waste and pathogens.
• Right Lymphatic Duct collects lymph from the right arm, right chest, and right side of the head.
• Right Subclavian Vein- Lymph re-enters the bloodstream, maintaining fluid balance.
• Removal of lymph nodes disrupts lymphatic system drainage > fluid retention > swelling.

Lymphedema

• Lymphedema is swelling due to blocked or damaged lymphatic drainage, caused by surgery, cancer treatment, or infection.
• Lymphedema causes fluid buildup in tissues, making it harder for the immune system to fight infections.

Cellulitis and Lymphedema

• Poor lymph drainage means bacteria are not cleared à increasing infection risk.
• Small cuts/scratches/insect bites allow bacteria to enter, triggering cellulitis.
• Antibiotics treat cellulitis and prevent serious complications: Preventing infection spread (sepsis), reducing swelling/inflammation, and avoiding recurrent infections (which further damage the lymphatic system).

Lymph Node Function

• Lymph nodes act as filters for lymph fluid, trapping bacteria, viruses, and other harmful substances before they reach the bloodstream.
• They contain immune cells (lymphocytes and macrophages) that detect/destroy pathogens.
• Lymph nodes activate an immune response when an infection is detected

Lymph Node Composition

• Lymphocytes (B cells and T cells) are the most abundant white blood cells in lymph nodes.
  • B cells produce antibodies to fight infections.
  • T cells help attack infected or abnormal cells.
• Lymph node swelling (lymphadenopathy) happens when the immune system is actively fighting an infection due to:
  • Increased lymphocyte production
  • Accumulation of trapped pathogens
  • Inflammation
• Afferent lymphatic vessels bring lymph into the node, efferent vessels carry it out.
  • There are more afferent (incoming) vessels than efferent (outgoing) vessels, which causes lymph to slow down inside the node.

Lymphatic Organs

• Lymph nodes are found in clusters (neck, armpits, groin) and filter lymph.
• The spleen removes old red blood cells and helps fight infections.
• The thymus is where T cells mature.
• Tonsils trap and destroy pathogens from food and air. Bone marrow produces white blood cells, including lymphocytes

Lymphoid Organs

• Primary lymphoid organs are where lymphocytes (B and T cells) develop and mature before entering circulation:
  • Bone Marrow produces B/T cells, B cells mature here.
  • Thymus: T cells travel from the bone marrow to mature here and become functional.
• Secondary lymphoid organs are where mature immune cells gather, interact, and respond to infections:
  • Lymph Nodes: Filter lymph and activate immune responses.
  • Spleen: Filters blood, removes old red blood cells, and helps fight infections.
  • Tonsils: Trap and destroy pathogens from food and air.
  • Mucosa-Associated Lymphoid Tissue (MALT): Includes Peyer's patches in the intestines, which monitor/fight gut infections.

Lacteals

• Lacteals are specialized lymphatic capillaries in the villi of the small intestine.
• Lacteals absorb dietary fats (lipids) from digested food, transport fats as chyle (a milky fluid containing fats and lymph) deliver absorbed fats into the lymphatic system (which eventually drains into the bloodstream for distribution).

Explore the vital functions of the lymphatic system, including fluid recovery, immune response, and lipid absorption. Learn about the mechanisms driving lymph flow, such as skeletal muscle contractions and valves, and the consequences of lymphatic system impairment.