Lymphatic System Notes

Lymphatic System Notes

• 1.
  Essentials of HumanAnatomy & Physiology Anatomy & Physiology II The Lymphatic System Mr. Hildebrandt
• 2.
  The Lymphatic System •Lymphatic system functions: • Transport clean fluids back to the blood • Drains excess fluids from tissues • Removes “debris” from cells of body • Transports fats from digestive system Slide 12.1
• 3.
  When things gowrong…..
• 4.
  Lymphatic Characteristics • Lymph– excess tissue fluid carried by lymphatic vessels • It’s a passive system: • One way system toward the heart • No pump • Lymph moves toward the heart • Milking action of skeletal muscle • Rhythmic contraction of smooth muscle in vessel walls • Gravity effects movement
• 5.
  Lymphatic Capillaries • Fluid leaks through mini-valves into lymph capillaries • Higher pressure on the inside closes mini-valves
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  Lymphatic Vessels • Collectslymph from lymph capillaries • Delivers lymph to lymph nodes • Returns fluid to circulatory veins near the heart • Right lymphatic duct • Thoracic duct
• 7.
  Lymphatic System Structures
• 8.
  Lymph Nodes • Filterlymph before it is returned to the blood • Defense cells in nodes: • Medulla houses macrophages which engulf and destroy foreign substances • Cortex nurtures lymphocytes which provide immune response to antigens (cortex)
• 9.
  Flow of LymphThrough Nodes • Lymph enters the convex side through afferent lymphatic vessels • Lymph flows through a number of sinuses inside the node • Lymph exits through efferent lymphatic vessels • Fewer efferent than afferent vessels causes flow to be slowed
• 10.
  Lymphoid Organs • Severalother organs contribute to lymphatic function • Spleen • Thymus • Tonsils • Peyer’s patches Figure 12.5
• 11.
  The Spleen • Filtersblood • Destroys worn out blood cells • Forms blood cells in the fetus • Acts as a blood reservoir
• 12.
  The Thymus • Functionsat peak levels only during childhood • Produces hormones (like thymosin) to program lymphocytes
• 13.
  Tonsils • Small massesof lymphoid tissue around the pharynx • Trap and remove bacteria and other foreign materials • Tonsillitis is caused by congestion with bacteria
• 14.
  Peyer’s Patches “Tonsilsof the intestine” • Found in the wall of the small intestine • Capture and destroy bacteria in the intestine
• 15.
  Mucosa-Associated Lymphatic Tissue (MALT) •Includes: • Peyer’s patches • Tonsils • Other small accumulations of lymphoid tissue • Acts as a sentinal to protect respiratory and digestive tracts