A and P Week 11

Lymphatic capillaries

Microscopic tubes making up network. Numerous with skin tissues

Lymph

Fluid

Lymphatic vessels

Formed by lymphatic capillaries. Unite to form larger vessels which empty into thoracic duct

Thoracic don’t

Largest lymphatic vessel of the body. Emptied entire body below diaphragm and left side above. Empties into left subclavian vein.

Right lymphatic duct

Another large vessel that drains right half of body above the diaphragm. Empties into right subclavian vein

Lymphatic system notes

One way. Valves.

Lymph nodes

Masses of tissue enclosed in capsule. Filtration mechanism for lymph b4 it returns to bloodstream. Contains T and B lymphocytes

Cortex

One of two lymph node regions. Outer region. Contains follicles which have terminal centers

Efferent lymphatic vessels

Leaving node

Afferent lymphatic vessels

Entering nodes

Lobules

Extensions of capsule pass into interior and separate lymph nodes into smaller parts

Reticular fibers

In lobules. Support main cells of nodes, B and T lymphocytes

Lymph sinuses

Spaces within lobules with relatively few cells. Lymph circulate through these regions

Medulla

One of two parts of lymph node. Central region with fewer lymphocytes.

Tonsils

Aggregates of lymph node tissue located under epithelial lining of oak and pharyngeal cavities.

Palatine tonsils

Located at surfaces of palatine bone

Pharyngeal tonsil aka adenoids

Roof of pharynx

Lingual tonsils

Tissue of tongue

Peyer’s patch

Nodules of lymphoid tissue found in wall of intestinal tract. Particularly ileum

Thymus

Organ of lymphatic system. Gland too. Similar in structure to spleen and lymph nodes. Matures T lymphocytes. Between lungs

Spleen

Lymphoid organ because functions are consistent with lymphatic system. Similar in shape to nodes and thymus. Below diaphragm left side. Shape conforms.

Hillus

Area where large blood vessels enter and leave the spleen

Splenic artery

Blood enters spleen by this way

Functions of spleen

Reservoir of lymphocytes, filters blood, red blood cell and iron metabolism, storage for blood, contractions B and T lymphocytes

Lacteals

Lymph vessels of intestinal wall holding milky fatty lymph

Edema

Accumulation of interstitial fluid in spaces between cells