Human Anatomy Mark Aaron Ch 22 Lymphatic REVIEW

Types of Lymphoid Cells

1. Lymphocytes

2. Lymphatic macrophages- phagocytize foreign cells

3. Dendritic cells- phagocytes

4. Reticular cells- protein fibers that support lymphoid organs

5. Neutrophils- aggressively attack and kill bacteria

Lymphocytes

T cells - directly attack foreign cells and manage immune responses

B cells - produce plasma cells that secrete antibodies

Lymphatic Vessels

Lymphatic Capillaries → Lymphatic Collecting Vessels → Lymphatic Trunks → Lymphatic Ducts

Lacteals

special lymphatic capillaries that transport fat from the small intestine ; fatty lymph is known as Chyle

Lymphatic Organs

1. Lymph Nodes

2. Spleen

3. Thymus Gland

4. Tonsils

5. Aggregates of lymphoid follicles

6. Red Bone marrow

Lymph Node Structure

Capsule- surrounds node

Trabecullae- connective tissue strands dividing node into chambers

Cortex- outer portion ; contains follicles where dividing B cells are located

Medulla- contains medullary cords which are inward extensions of lymphatic tissue (contain plasma cells)

Lymph Sinuses- fill central portion of node ; contain lymphocytes and macrophages

Circulation in Lymph Nodes

lymph enters nodes via afferent lymphatic vessels → subcapsular sinus → smaller sinuses → exited at hilus near efferent lymphatic vessels

Spleen

white pulp- store lymphocytes

red pulp- remove red blood cells ; made up by splenic cords

Tonsils

1. palatine - largest

2. linguinal - base of tongue

3. pharyngeal - nasopharynx ; adenoids when enlarged

4. tubal - openings of eustachian tubes into pharynx

Aggregates of Lymphoid Follicles

Peyer’s Patches- similar to tonsils in small intestine ; destroy bacteria and provide long term immunity

Vermiform Appendix- large intesting