Lecture Notes: Blood Vessels, Liver Blood Supply, and Lymphatic System

Blood Supply to the Liver

• Hepatic Artery:
  • Provides oxygenated blood to the liver.
  • Originates from the celiac artery, which comes from the abdominal aorta.
• Hepatic Portal Vein:
  • Brings nutrients from the stomach and small intestine to the liver.

Disorders of Blood Vessels

• Aneurysms:
  • Definition: Weakening and swelling of a vessel wall.
  • Example: Aortic arch aneurysm can be replaced with a Dacron sleeve.
  • Post-surgery: Heparin is given to prevent clotting due to potential unsmooth surfaces.
• Hypertension:
  • Defined as high blood pressure (threshold: 140/90 mmHg).
  • Normal blood pressure: 120/80 mmHg.
  • Methods to reduce: Meditation, Tai Chi, Yoga.
• Varicose Veins:
  • Swelling of superficial veins, typically in lower extremities.
  • Causes: Obesity, pregnancy, hereditary factors.
  • Prevention: Exercise, maintaining healthy weight.

Lymphatic System

• Components:
  • Lymphatic tissue and vessels, lymph fluid.
  • Tissues include spleen, lymph nodes, thymus, tonsils, and Peyer's patches.

Spleen

• Function:
  • Filters blood, destroys old RBCs (120 days lifespan), produces lymphocytes.
• Structure:
  • Largest mass of lymphatic tissue.
  • Located in upper left abdominal quadrant.
  • Covered by connective tissue capsule and peritoneum.
  • Contains trabeculae, reticulum of reticular fibers, macrophages.
  • Blood supply: Splenic artery and vein.
  • White pulp and red pulp regions.

Lymph Nodes

• Description:

  • Small, oval bodies (1 mm to several cm).
  • Found in groups: cervical, axillary, inguinal.
  • Important for detecting infections and cancer metastasis (e.g., breast cancer).

• Function:

  • Filter lymph, produce lymphocytes and plasma cells.
  • Afferent and efferent vessels manage lymph flow.

Lymph Fluid

• Composed of tissue fluid (water, proteins, sugars, fats).
• Essential for returning proteins to blood, preventing fatal buildup.
• Fat absorption through lacteals in small intestine.
  • Transported via thoracic duct to venous system at the base of the neck (internal jugular and subclavian veins).

Examples of Lymphatic Tissue

• Thymus: Contains Hassall's corpuscles (function unknown).
• Tonsils: Located at oral cavity, produce lymphocytes.
• Peyer's Patches: Located in ileum, numerous lymphatic tissue masses.

Summary

• The lymphatic system plays a crucial role in maintaining fluid balance, filtering lymph and supporting immune function.
• Its components are closely aligned with the blood vascular system but operate independently in many respects.
• Understanding the lymphatic system's pathways is important for studying disease progression and immune response.