Histo lec lymphoid organs Flashcards
Primary organs of the lymphoid (2)
o Thymus
o Bone marrow
Secondary organs of the lymphoid (4)
o Tonsils
o Lymph nodes
o Spleen
o Mucosa associated lymphoid tissue
Provides defense against infectious diseases
Lymphoid organs
What organ
o Location: Mediastinum
o Main function: Induction f central tolerance
- Produce T cells
o Undergoes Involution during puberty (small in adult)
Thymus
Hassal Corpuscles
Medulla
What organ
o Mucosa of digestive, respiratory, and genitourinary tracts
o Tonsils and appendix
o Collection f lymphocytes, plasma cells, APCs and lymphoid nodules
o Most lymphocytes are B cells
MALT
Tonsil Types (3)
Palatine
Lingual
Pharyngeal
What organ
o Bean shaped encapsulated structure
o In line filters of lymph
o Convex surface
-_____________
o Concave surface
-________________
-________________
Lymph nodes
Afferent lymphatics
Efferent lymphatics
Artery, vein, nerve
What organ
o largest single accumulating f lymphoid tissue in the body
o Only lymphoid organ involved in filtration of blood
o Site of old erythrocytic destruction
Spleen
What organ
Cortex/Medulla: Distinctly present
Lymphoid nodules: Absent
Lymphatic vessels: No afferents; few efferents in septa
Unique features: hassal corpuscles in medulla; reticular cells in cortex and medulla
Thymus
What organ
Cortex/Medulla: Absent
Lymphoid nodules: Present
Lymphatic vessels: No afferent; efferents present
Unique features: Crypt lined by surface by surface in tonsils; epithelial M cells in mucosa over Peyer patches
MALT
What organ
Cortex/Medulla: Present
Lymphoid nodules: Present in cortex only
Lymphatic vessels: Afferents at capsule emptying into subcapsular sinus; efferent at hilum
Unique features: Thin [paracortical region between cortex and medulla, with high endothelial venules; medullary cords and sinuses
Lymph nodes
What organ
Cortex/Medulla: Absent
Lymphoid nodules: present in white pulp only
Lymphatic vessels: No afferents; efferents in trabeculae
Unique features: Minor white pulp component, with central arterioles; major red pulp component with many sinusoids
Spleen
