Human Anatomy and Physiology

Lymphatic system

Components 1. Lymphatic vessels

‘Mop up’ fluid escaped from vasculature

Lymphatic vessels A one-way system to the heart Absent in bones, teeth, CNS

Lymphatic vessels Structure

Minivalves and collagenfibers

Valve opens when interstitial pressure rises

Lymphatic vessels Structure

Proteins, fat travel via lymph (lacteals)

Cancer travels via lymph Lymph nodes (macrophages, lymphocytes) Slow circulation depends on muscle

contraction and action of respiration

Components 2. Lymphatics cells and tissue

House phagocytic cells (cells that engulf) and lymphocytes (T and B cells) used in defense

Tissue composed mostly of reticular CT

Lymph organs

Lymph organs

1. Lymph nodes Macrophages in nodes destroy microorganisms Contain lymphocytes that destroy antigens

2. Spleen Provides for lymphocyte proliferation and immune

surveillance because it filters blood 3. Thymus

Causes T lymphocytes to become immunocompetent

Lymph organs

4. Tonsils Bacteria enter blind-ending sacs of tonsils and through

epithelium into lymphoid tissue to be destroyed 5. Peyer’s patches

Destroy bacteria in large numbers on intestine wall and appendix prior to breaching intestinal wall